Initial incomplete GLU NURBS port under net.java.games.jogl.impl.nurbs

and a small README about the procedures being used during the port


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/jogl/trunk@180 232f8b59-042b-4e1e-8c03-345bb8c30851

13 files changed, 3485 insertions, 0 deletions

diff --git a/src/net/java/games/jogl/impl/nurbs/README-PORTING.txt b/src/net/java/games/jogl/impl/nurbs/README-PORTING.txt
new file mode 100755
index 000000000..df5f41782
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/README-PORTING.txt
@@ -0,0 +1,40 @@
+This is a currently incomplete port of SGI's GLU NURBS library from
+C++ to Java. There are a few reasons for doing such a port:
+
+ - The C interface is structured around function pointers. It is
+   generally difficult to bind such interfaces up to Java.
+
+ - Some people have reported crashes on certain Linux distributions
+   when trying to use any routines out of the C GLU library. To date
+   we have not been able to diagnose the root cause of these failures.
+   Porting the code involved from C++ to Java has solved these
+   problems.
+
+The port so far has been started in the internals/ directory. The C++
+sources have been gone through roughly alphabetically and
+transliterated into the appropriate files. The large Subdivider class
+was the current focus of attention at the time of this writing, and a
+closer look indicates that at least a few classes were skipped on the
+way down to some of the Subdivider's sources like intersect.cc. It may
+be a good idea to continue the port in this directory first, since it
+looks like the other directories' sources are built on top of these
+and it would be good to firm up the Java interfaces for the internals
+(and perhaps get the sources to compile) before porting lots of code
+built on top of them.
+
+A couple of notes on the translation:
+
+ - All object pool classes have been removed. The intention is to have
+   a static allocate() method on the appropriate classes which will
+   instantiate populated arrays of these types (not just arrays of
+   null references). See uses of TrimVertex.allocate().
+
+ - There are a significant number of places in the original C++ code
+   where pointer arithmetic is used. Some of these are not obvious
+   until the code has been ported and examined. Bin.java was a good
+   example of this where the algorithms needed some restructuring. At
+   the time of this writing intersect.cc was in the process of being
+   ported and it wasn't clear whether we would need to change some of
+   the APIs or add more utility routines to be able to do pointer
+   arithmetic on, for example, the TrimVertex arrays returned from the
+   allocate() routine.
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/Arc.java b/src/net/java/games/jogl/impl/nurbs/internals/Arc.java
new file mode 100755
index 000000000..076c68b72
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/Arc.java
@@ -0,0 +1,274 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+/* an arc, in two list, the trim list and bin */
+public class Arc {
+  public static final int SIDE_NONE   = 0;
+  public static final int SIDE_RIGHT  = 1;
+  public static final int SIDE_TOP    = 2;
+  public static final int SIDE_LEFT   = 3;
+  public static final int SIDE_BOTTOM = 4;
+
+  public static final int bezier_tag = (1 << 13);
+  public static final int arc_tag    = (1 <<  3);
+  public static final int tail_tag   = (1 <<  6);
+  public Arc    prev;  /* trim list pointer */
+  public Arc    next;  /* trim list pointer */
+  public Arc    link;  /* bin pointers */
+  public BezierArc bezierArc; /* associated bezier arc */
+  public PwlArc    pwlArc;    /* associated pwl arc */
+  public long      type;      /* curve type */
+  public long      nuid;
+
+  private static final float ZERO = 0.00001f;
+
+  public Arc(Arc j, PwlArc p) {
+    pwlArc = p;
+    type = j.type;
+    nuid = j.nuid;
+  }
+
+  public Arc(int arcSide, long nuid) {
+    type = 0;
+    setside(arcSide);
+    this.nuid = nuid;
+  }
+
+  public Arc append(Arc jarc) {
+    if ( jarc != null ) {
+      next = jarc.next;
+      prev = jarc;
+      next.prev = prev.next = this;
+    } else {
+      next = prev = this;
+    }
+    return this;
+  }
+
+  public boolean check() {
+    Arc jarc = this;
+    do {
+      assert( (jarc.pwlArc != null) || (jarc.bezierArc != null) );
+
+      if (jarc.prev == 0 || jarc.next == 0) {
+        System.out.println( "checkjarc:null next/prev pointer");
+        jarc.print( );
+        return false;
+      }
+
+      if (jarc.next.prev != jarc) {
+        System.out.println( "checkjarc: pointer linkage screwed up");
+        jarc.print( );
+        return false;
+      }
+
+      if( jarc.pwlArc != null ) {
+        assert( jarc.pwlArc.npts >= 1 );
+        assert( jarc.pwlArc.npts < 100000 );
+        if( jarc.prev.pwlArc != null ) {
+          if( jarc.tail()[1] != jarc.prev.rhead()[1] ) {
+            System.out.println( "checkjarc: geometric linkage screwed up 1");
+            jarc.prev.show();
+            jarc.show();
+            return false;
+          }
+          if( jarc.tail()[0] != jarc.prev.rhead()[0] ) {
+            System.out.println( "checkjarc: geometric linkage screwed up 2");
+            jarc.prev.show();
+            jarc.show();
+            return false;
+          }
+        }
+        if( jarc.next.pwlArc ) {
+          if( jarc.next.tail()[0] != jarc.rhead()[0] ) {
+            System.out.println( "checkjarc: geometric linkage screwed up 3");
+            jarc.show();
+            jarc.next.show();
+            return false;
+          }
+          if( jarc.next.tail()[1] != jarc.rhead()[1] ) {
+            System.out.println( "checkjarc: geometric linkage screwed up 4");
+            jarc.show();
+            jarc.next.show();
+            return false;
+          }
+        }
+        if( jarc.isbezier() ) {
+          assert( jarc.pwlArc.npts == 2 );
+          assert( (jarc.pwlArc.pts[0].param[0] ==
+                   jarc.pwlArc.pts[1].param[0]) ||
+                  (jarc.pwlArc.pts[0].param[1] ==
+                   jarc.pwlArc.pts[1].param[1]) );
+        }
+      }
+      jarc = jarc.next;
+    } while (jarc != this);
+    return true;
+  }
+
+  /**
+   * Checks if tail of arc and head of prev meet.
+   */
+  public boolean isDisconnected() {
+    if( pwlArc == 0 ) return 0;
+    if( prev.pwlArc == 0 ) return 0;
+
+    float[] p0 = tail();
+    float[] p1 = prev.rhead();
+
+    if( ((p0[0] - p1[0]) > ZERO) || ((p1[0] - p0[0]) > ZERO) ||
+	((p0[1] - p1[1]) > ZERO) || ((p1[1] - p0[1]) > ZERO)  ) {
+      return true;
+    } else {
+      /* average two points together */
+      p0[0] = p1[0] = (p1[0] + p0[0]) * 0.5f;
+      p0[1] = p1[1] = (p1[1] + p0[1]) * 0.5f;
+      return false;
+    }
+  }
+
+  /**
+   * Counts number of points on arc loop.
+   */
+  public int numpts( ) {
+    Arc jarc = this;
+    int npts = 0;
+    do {
+	npts += jarc.pwlArc.npts;
+	jarc = jarc.next;
+    } while( jarc != this );
+    return npts;
+  }
+
+  /**
+   * Marks each point with id of arc.
+   */
+  public void markverts( void ) {
+    Arc jarc = this;
+	
+    do {
+	TrimVertex p = jarc.pwlArc.pts;
+	for( int i=0; i<jarc.pwlArc.npts; i++ )
+	    p[i].nuid = jarc.nuid;
+	jarc = jarc.next;
+    } while( jarc != this );
+  }
+
+  /**
+   * Finds axis extrema on arc loop.
+   */
+  public void    getextrema( Arc[4] ) {
+    float leftpt, botpt, rightpt, toppt;
+
+    extrema[0] = extrema[1] = extrema[2] = extrema[3] = this;
+
+    leftpt = rightpt = this.tail()[0];
+    botpt  = toppt   = this.tail()[1];
+
+    for( Arc jarc = this.next; jarc != this; jarc = jarc.next ) {
+	if ( jarc.tail()[0] <  leftpt || 
+	    (jarc.tail()[0] <= leftpt && jarc.rhead()[0]<=leftpt))  {
+	    leftpt = jarc.pwlArc.pts.param[0];
+	    extrema[1] = jarc;
+	}
+	if ( jarc.tail()[0] >  rightpt || 
+	    (jarc.tail()[0] >= rightpt && jarc.rhead()[0] >= rightpt)) {
+	    rightpt = jarc.pwlArc.pts.param[0];
+	    extrema[3] = jarc;
+	}
+	if ( jarc.tail()[1] <  botpt || 
+            (jarc.tail()[1] <= botpt && jarc.rhead()[1] <= botpt ))  {
+	    botpt = jarc.pwlArc.pts.param[1];
+	    extrema[2] = jarc;
+	}
+	if ( jarc.tail()[1] >  toppt || 
+	    (jarc.tail()[1] >= toppt && jarc.rhead()[1] >= toppt))  {
+	    toppt = jarc.pwlArc.pts.param[1];
+	    extrema[0] = jarc;
+	}
+    }
+  }
+
+  /**
+   * Prints out the vertices of all pwl arcs on a loop.
+   */
+  public void    print( ) {
+    Arc jarc = this;
+
+    do {
+      jarc.show( );
+      jarc = jarc.next;
+    } while (jarc != this);
+  }
+
+  public void    show( ) {
+    System.out.println( "\tPWLARC NP: " + pwlArc.npts + " FL: 1");
+    for( int i = 0; i < pwlArc.npts; i++ ) {
+      System.out.println( "\t\tVERTEX " + pwlArc.pts[i].param[0] + " " +
+                          pwlArc.pts[i].param[1] );
+    }
+  }
+
+  /**
+   * Attaches a pwl arc to an arc and mark it as a border arc.
+   */
+  public void    makeSide( PwlArc pwl, int arcSide ) {
+    assert( pwl != 0);
+    assert( pwlArc == 0 );
+    assert( pwl.npts > 0 );
+    assert( pwl.pts != 0);
+    pwlArc = pwl;
+    clearbezier();
+    setside( arcSide );
+  }
+
+  public boolean      isTessellated()        { return (pwlArc != null); }
+  public boolean      isbezier()             { return (type & bezier_tag) != 0; }
+  public void         setbezier()            { type |= bezier_tag; }
+  public void         clearbezier()          { type &= ~bezier_tag; }
+  public long         npts()                 { return pwlArc.npts; }
+  public TrimVertex[] pts()                  { return pwlArc.pts; }
+  public float[]      tail()                 { return pwlArc.pts[0].param; }
+  public float[]      head()                 { return next.pwlArc.pts[0].param; }
+  public float[]      rhead()                { return pwlArc.pts[pwlArc.npts-1].param; }
+  public long         ismarked()             { return type & arc_tag; }
+  public void         setmark()              { type |= arc_tag; }
+  public void         clearmark()            { type &= (~arc_tag); }
+  public void         clearside()            { type &= ~(0x7 << 8); }
+  public void         setside( int arcSide ) { clearside(); type |= (((long)arcSide)<<8); }
+  public int          getside()              { return ((type>>8) & 0x7); }
+  public int          getitail()             { return type & tail_tag; }
+  public void         setitail()             { type |= tail_tag; }
+  public void         clearitail()           { type &= (~tail_tag); }
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/ArcTesselator.java b/src/net/java/games/jogl/impl/nurbs/internals/ArcTesselator.java
new file mode 100755
index 000000000..cb77dfbd0
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/ArcTesselator.java
@@ -0,0 +1,449 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class ArcTessellator {
+  /**
+   * Constructs a bezier arc and attaches it to an Arc.
+   */
+  public void bezier( Arc arc, float s1, float s2, float t1, float t2 ) {
+    assert( arc != null );
+    assert( ! arc.isTessellated() );
+
+    switch( arc.getside() ) {
+      case Arc.SIDE_LEFT:
+        assert( s1 == s2 );
+        assert( t2 < t1 );
+        break;
+      case Arc.SIDE_RIGHT:
+        assert( s1 == s2 );
+        assert( t1 < t2 );
+        break;
+      case Arc.SIDE_TOP:
+        assert( t1 == t2 );
+        assert( s2 < s1 );
+        break;
+      case Arc.SIDE_BOTTOM:
+        assert( t1 == t2 );
+        assert( s1 < s2 );
+        break;
+      case Arc.SIDE_NONE:
+        throw new InternalError();
+        break;
+    }
+    
+    TrimVertex[] p = TrimVertex.allocate(2);
+    arc.pwlArc = new PwlArc( p );
+    p[0].param[0] = s1;
+    p[0].param[1] = t1;
+    p[1].param[0] = s2;
+    p[1].param[1] = t2;
+    assert( (s1 == s2) || (t1 == t2) );
+    arc.setbezier();
+  }
+
+  /**
+   * Constructs a pwl arc and attaches it to an arc.
+   */
+  public void pwl( Arc arc, float s1, float s2, float t1, float t2, float rate ) {
+    int snsteps = 1 + (int) (Math.abs(s2 - s1) / rate );
+    int tnsteps = 1 + (int) (Math.abs(t2 - t1) / rate );
+    int nsteps = (int) Math.max(1, Math.max( snsteps, tnsteps ));
+
+    float sstepsize = (s2 - s1) / (float) nsteps;
+    float tstepsize = (t2 - t1) / (float) nsteps;
+    TrimVertex[] newvert = TrimVertex.allocate( nsteps+1 );
+    long i;
+    for( i = 0; i < nsteps; i++ ) {
+	newvert[i].param[0] = s1;
+	newvert[i].param[1] = t1;
+	s1 += sstepsize;
+	t1 += tstepsize;
+    }
+    newvert[i].param[0] = s2;
+    newvert[i].param[1] = t2;
+
+    arc.pwlArc = new PwlArc( newvert );
+
+    arc.clearbezier();
+    arc.clearside( );
+  }
+
+  /**
+   * Constructs a left boundary pwl arc and attaches it to an arc.
+   */
+  public void pwl_left( Arc arc, float s, float t1, float t2, float rate ) {
+    assert( t2 < t1 );
+
+    int nsteps = steps_function(t1, t2, rate);
+
+    float stepsize = (t1 - t2) / (float) nsteps;
+
+    TrimVertex[] newvert = TrimVertex.allocate( nsteps+1 );
+    int i;
+    for( i = nsteps; i > 0; i-- ) {
+	newvert[i].param[0] = s;
+	newvert[i].param[1] = t2;
+	t2 += stepsize;
+    }
+    newvert[i].param[0] = s;
+    newvert[i].param[1] = t1;
+
+    arc.makeSide( new PwlArc( newvert ), Arc.SIDE_LEFT );
+  }
+
+  /**
+   * Constructs a right boundary pwl arc and attaches it to an arc.
+   */
+  public void pwl_right( Arc arc, float s, float t1, float t2, float rate ) {
+    assert( t1 < t2 );
+
+    int nsteps = steps_function(t2,t1,rate);
+    float stepsize = (t2 - t1) / (float) nsteps;
+
+    TrimVertex[] newvert = TrimVertex.allocate( nsteps+1 );
+    int i;
+    for( i = 0; i < nsteps; i++ ) {
+	newvert[i].param[0] = s;
+	newvert[i].param[1] = t1;
+	t1 += stepsize;
+    }
+    newvert[i].param[0] = s;
+    newvert[i].param[1] = t2;
+
+    arc.makeSide( new PwlArc( newvert ), Arc.SIDE_RIGHT );
+  }
+
+  /**
+   * Constructs a top boundary pwl arc and attaches it to an arc.
+   */
+  public void pwl_top( Arc arc, float t, float s1, float s2, float rate ) {
+    assert( s2 < s1 );
+
+    int nsteps = steps_function(s1,s2,rate);
+    float stepsize = (s1 - s2) / (float) nsteps;
+
+    TrimVertex[] newvert = TrimVertex.allocate( nsteps+1 );
+    int i;
+    for( i = nsteps; i > 0; i-- ) {
+	newvert[i].param[0] = s2;
+	newvert[i].param[1] = t;
+	s2 += stepsize;
+    }
+    newvert[i].param[0] = s1;
+    newvert[i].param[1] = t;
+
+    arc.makeSide( new PwlArc( newvert ), Arc.SIDE_TOP );
+  }
+
+  /**
+   * Constructs a bottom boundary pwl arc and attaches it to an arc.
+   */
+  public void pwl_bottom( Arc arc, float t, float s1, float s2, float rate ) {
+    assert( s1 < s2 );
+
+    int nsteps = steps_function(s2,s1,rate);
+    float stepsize = (s2 - s1) / (float) nsteps;
+
+    TrimVertex[] newvert = TrimVertex.allocate( nsteps+1 );
+    int i;
+    for( i = 0; i < nsteps; i++ ) {
+	newvert[i].param[0] = s1;
+	newvert[i].param[1] = t;
+	s1 += stepsize;
+    }
+    newvert[i].param[0] = s2;
+    newvert[i].param[1] = t;
+
+    arc.makeSide( new PwlArc( newvert ), Arc.SIDE_BOTTOM );
+  }
+
+  /**
+   * Constucts a linear pwl arc and attaches it to an Arc.
+   */
+  public void tessellateLinear( Arc arc, float geo_stepsize, float arc_stepsize, boolean isrational ) {
+    assert( arc.pwlArc == null );
+    float s1, s2, t1, t2;
+
+    //we don't need to scale by arc_stepsize if the trim curve
+    //is piecewise linear. Reason: In pwl_right, pwl_left, pwl_top, pwl_left,
+    //and pwl, the nsteps is computed by deltaU (or V) /stepsize. 
+    //The quantity deltaU/arc_stepsize doesn't have any meaning. And
+    //it causes problems: see bug 517641
+    float stepsize = geo_stepsize; /* * arc_stepsize*/;
+
+    BezierArc b = arc.bezierArc;
+
+    if( isrational ) {
+	s1 = b.cpts[0] / b.cpts[2];
+	t1 = b.cpts[1] / b.cpts[2];
+	s2 = b.cpts[b.stride+0] / b.cpts[b.stride+2];
+	t2 = b.cpts[b.stride+1] / b.cpts[b.stride+2];
+    } else {
+	s1 = b.cpts[0];
+	t1 = b.cpts[1];
+	s2 = b.cpts[b.stride+0];
+	t2 = b.cpts[b.stride+1];
+    }
+    if( s1 == s2 )
+	if( t1 < t2 )
+	    pwl_right( arc, s1, t1, t2, stepsize );
+	else
+	    pwl_left( arc, s1, t1, t2, stepsize );
+    else if( t1 == t2 )
+	if( s1 < s2 ) 
+	    pwl_bottom( arc, t1, s1, s2, stepsize );
+	else
+	    pwl_top( arc, t1, s1, s2, stepsize );
+    else
+	pwl( arc, s1, s2, t1, t2, stepsize );
+  }
+
+  /**
+   * Constucts a nonlinear pwl arc and attaches it to an Arc.
+   */
+  public void tessellateNonlinear( Arc arc, float geo_stepsize, float arc_stepsize, int isrational ) {
+    assert( arc.pwlArc == null );
+
+    float stepsize = geo_stepsize * arc_stepsize;
+
+    BezierArc *bezierArc = arc.bezierArc;
+
+    float size; //bounding box size of the curve in UV 
+    {
+      int i,j;
+      float min_u, min_v, max_u,max_v;
+      min_u = max_u = bezierArc.cpts[0];
+      min_v = max_v = bezierArc.cpts[1];
+      for(i=1, j=2; i<bezierArc.order; i++, j+= bezierArc.stride)
+        {
+          if(bezierArc.cpts[j] < min_u)
+            min_u = bezierArc.cpts[j];
+          if(bezierArc.cpts[j] > max_u)
+            max_u = bezierArc.cpts[j];
+          if(bezierArc.cpts[j+1] < min_v)
+            min_v = bezierArc.cpts[j+1];   
+          if(bezierArc.cpts[j+1] > max_v)
+            max_v = bezierArc.cpts[j+1]; 
+        }
+
+      size = max_u - min_u;
+      if(size < max_v - min_v)
+        size = max_v - min_v;
+    }
+      
+    /*int nsteps   = 1 + (int) (1.0/stepsize);*/
+
+    int nsteps = (int) (size/stepsize);
+    if(nsteps <=0)
+      nsteps=1;
+
+    TrimVertex[] vert = TrimVertex.allocate( nsteps+1 );
+    float dp   = 1.0/nsteps;
+    int vi = 0; // vertIdx
+
+    arc.pwlArc  = new PwlArc();
+    arc.pwlArc.pts  = vert;
+
+    if( isrational ) {
+      float[] pow_u = new float[Defines.MAXORDER];
+      float[] pow_v = new float[Defines.MAXORDER];
+      float[] pow_w = new float[Defines.MAXORDER];
+      trim_power_coeffs( bezierArc, pow_u, 0 );
+      trim_power_coeffs( bezierArc, pow_v, 1 );
+      trim_power_coeffs( bezierArc, pow_w, 2 );
+
+      /* compute first point exactly */
+      float[] b = bezierArc.cpts;
+      vert[vi].param[0] = b[0]/b[2];
+      vert[vi].param[1] = b[1]/b[2];
+
+      /* strength reduction on p = dp * step would introduce error */
+      long order = bezierArc.order;
+      for( int step=1, ++vi; step<nsteps; step++, vi++ ) {
+        float p = dp * step;
+        float u = pow_u[0];
+        float v = pow_v[0];
+        float w = pow_w[0];
+        for( int i = 1; i < order; i++ ) {
+          u = u * p + pow_u[i];
+          v = v * p + pow_v[i];
+          w = w * p + pow_w[i];
+        }
+        vert[vi].param[0] = u/w;
+        vert[vi].param[1] = v/w;
+      }
+
+      /* compute last point exactly */
+      b += (order - 1) * bezierArc.stride;
+      vert[vi].param[0] = b[0]/b[2];
+      vert[vi].param[1] = b[1]/b[2];
+
+    } else {
+      float[] pow_u = new float[Defines.MAXORDER];
+      float[] pow_v = new float[Defines.MAXORDER];
+      trim_power_coeffs( bezierArc, pow_u, 0 );
+      trim_power_coeffs( bezierArc, pow_v, 1 );
+
+      /* compute first point exactly */
+      float[] b = bezierArc.cpts;
+      vert[vi].param[0] = b[0];
+      vert[vi].param[1] = b[1];
+
+      /* strength reduction on p = dp * step would introduce error */
+      long order =  bezierArc.order;
+      for( int step=1, ++vi; step<nsteps; step++, vi++ ) {
+        float p = dp * step;
+        float u = pow_u[0];
+        float v = pow_v[0];
+        for( int i = 1; i < bezierArc.order; i++ ) {
+          u = u * p + pow_u[i];
+          v = v * p + pow_v[i];
+        }
+        vert[vi].param[0] = u;
+        vert[vi].param[1] = v;
+      }
+
+      /* compute last point exactly */
+      b += (order - 1) * bezierArc.stride;
+      vert[vi].param[0] = b[0];
+      vert[vi].param[1] = b[1];
+    }
+    arc.pwlArc.npts = vi + 1;
+  }
+
+  private static final float gl_Bernstein[][Defines.MAXORDER][Defines.MAXORDER] = {
+    {
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {-1, 1, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {1, -2, 1, 0, 0, 0, 0, 0 },
+      {-2, 2, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {-1, 3, -3, 1, 0, 0, 0, 0 },
+      {3, -6, 3, 0, 0, 0, 0, 0 },
+      {-3, 3, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {1, -4, 6, -4, 1, 0, 0, 0 },
+      {-4, 12, -12, 4, 0, 0, 0, 0 },
+      {6, -12, 6, 0, 0, 0, 0, 0 },
+      {-4, 4, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {-1, 5, -10, 10, -5, 1, 0, 0 },
+      {5, -20, 30, -20, 5, 0, 0, 0 },
+      {-10, 30, -30, 10, 0, 0, 0, 0 },
+      {10, -20, 10, 0, 0, 0, 0, 0 },
+      {-5, 5, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {1, -6, 15, -20, 15, -6, 1, 0 },
+      {-6, 30, -60, 60, -30, 6, 0, 0 },
+      {15, -60, 90, -60, 15, 0, 0, 0 },
+      {-20, 60, -60, 20, 0, 0, 0, 0 },
+      {15, -30, 15, 0, 0, 0, 0, 0 },
+      {-6, 6, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 },
+      {0, 0, 0, 0, 0, 0, 0, 0 }
+    },
+    {
+      {-1, 7, -21, 35, -35, 21, -7, 1 },
+      {7, -42, 105, -140, 105, -42, 7, 0 },
+      {-21, 105, -210, 210, -105, 21, 0, 0 },
+      {35, -140, 210, -140, 35, 0, 0, 0 },
+      {-35, 105, -105, 35, 0, 0, 0, 0 },
+      {21, -42, 21, 0, 0, 0, 0, 0 },
+      {-7, 7, 0, 0, 0, 0, 0, 0 },
+      {1, 0, 0, 0, 0, 0, 0, 0 }
+    }
+  };
+
+  /**
+   * Computes power basis coefficients from bezier coeffients.
+   */
+  private static void trim_power_coeffs( BezierArc bez_arc, float[] p, int coord ) {
+    int stride = bez_arc.stride;
+    int order = bez_arc.order;
+    float[] base = bez_arc.cpts;
+    int baseIdx = coord;
+
+    float[][] mat  = gl_Bernstein[order-1];
+
+    for (int i = 0; i < order; i++) {
+      float[] row = mat[i];
+      float s = 0.0f;
+      int pointIdx = baseIdx;
+      for (int j = 0; j < order; j++, pointIdx += stride) {
+        s += row[j] * base[pointIdx];
+      }
+      p[i] = s;
+    }
+  }
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/Backend.java b/src/net/java/games/jogl/impl/nurbs/internals/Backend.java
new file mode 100755
index 000000000..e99822f0b
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/Backend.java
@@ -0,0 +1,377 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class Backend {
+  private BasicCurveEvaluator curveEvaluator;
+  private BasicSurfaceEvaluator surfaceEvaluator;
+
+  public Backend( BasicCurveEvaluator c, BasicSurfaceEvaluator e ) {
+    this.c = c;
+    this.e = e;
+  }
+
+  /* surface backend routines */
+
+  /**
+   * bgnsurf - preamble to surface definition and evaluations
+   */
+  public void bgnsurf( boolean wiretris, boolean wirequads, long nuid ) {
+    wireframetris = wiretris;
+    wireframequads = wirequads;
+
+    /*in the spec, GLU_DISPLAY_MODE is either
+     * GLU_FILL
+     * GLU_OUTLINE_POLY
+     * GLU_OUTLINE_PATCH.
+     *In fact, GLU_FLL is has the same effect as
+     * set GL_FRONT_AND_BACK to be GL_FILL
+     * and GLU_OUTLINE_POLY is the same as set 
+     *     GL_FRONT_AND_BACK to be GL_LINE
+     *It is more efficient to do this once at the beginning of
+     *each surface than to do it for each primitive.
+     *   The internal has more options: outline_triangle and outline_quad
+     *can be seperated. But since this is not in spec, and more importantly,
+     *this is not so useful, so we don't need to keep this option.
+     */
+
+    surfaceEvaluator.bgnmap2f( nuid );
+
+    if(wiretris)
+      surfaceEvaluator.polymode(N_MESHLINE);
+    else
+      surfaceEvaluator.polymode(N_MESHFILL);
+  }
+
+  public void patch( float ulo, float uhi, float vlo, float vhi ) {
+    surfaceEvaluator.domain2f( ulo, uhi, vlo, vhi );
+  }
+
+  /**
+   * surfpts - pass a desription of a surface map
+   */
+  public void surfpts(long type,    /* geometry, color, texture, normal      */
+                      float[] pts,  /* control points                        */
+                      long ustride, /* distance to next point in u direction */
+                      long vstride, /* distance to next point in v direction */
+                      int uorder,   /* u parametric order                    */
+                      int vorder,   /* v parametric order                    */
+                      float ulo,    /* u lower bound                         */
+                      float uhi,    /* u upper bound                         */
+                      float vlo,    /* v lower bound                         */
+                      float vhi     /* v upper bound                         */ ) {
+    surfaceEvaluator.map2f( type,ulo,uhi,ustride,uorder,vlo,vhi,vstride,vorder,pts );
+    surfaceEvaluator.enable( type );
+  }
+  public void surfbbox( long type, float[] from, float[] to ) {
+    surfaceEvaluator.range2f( type, from, to );
+  }
+  /**
+   * surfgrid - define a lattice of points with origin and offset
+   */
+  public void surfgrid( float u0, float u1, long nu, float v0, float v1, long nv ) {
+    surfaceEvaluator.mapgrid2f( nu, u0, u1, nv, v0, v1 );
+  }
+  /**
+   * surfmesh - evaluate a mesh of points on lattice
+   */
+  public void surfmesh( long u, long v, long n, long m ) {
+    if( wireframequads ) {
+      long v0,  v1;
+      long u0f = u, u1f = u+n;
+      long v0f = v, v1f = v+m;
+      long parity = (u & 1);
+
+      for( v0 = v0f, v1 = v0f++ ; v0<v1f; v0 = v1, v1++ ) {
+        surfaceEvaluator.bgnline();
+        for( long u = u0f; u<=u1f; u++ ) {
+          if( parity ) {
+            surfaceEvaluator.evalpoint2i( u, v0 );
+            surfaceEvaluator.evalpoint2i( u, v1 );
+          } else {
+            surfaceEvaluator.evalpoint2i( u, v1 );
+            surfaceEvaluator.evalpoint2i( u, v0 );
+          }
+          parity = 1 - parity;
+        }
+        surfaceEvaluator.endline();
+      }
+    } else {
+      surfaceEvaluator.mapmesh2f( N_MESHFILL, u, u+n, v, v+m );
+    }
+  }
+  /**
+   * bgntmesh - preamble to a triangle mesh
+   */
+  public void bgntmesh() {
+    meshindex = 0;	/* I think these need to be initialized to zero */
+    npts = 0;
+
+    if( !wireframetris ) {
+      surfaceEvaluator.bgntmesh();
+    }
+  }
+  /**
+   * endtmesh - postamble to triangle mesh
+   */
+  public void endtmesh( ) {
+    if( ! wireframetris )
+      surfaceEvaluator.endtmesh();
+  }
+  /**
+   * swaptmesh - perform a swap of the triangle mesh pointers
+   */
+  public void swaptmesh( ) {
+    if( wireframetris ) {
+      meshindex = 1 - meshindex;
+    } else {
+      surfaceEvaluator.swaptmesh();
+    }
+  }
+  public void tmeshvert( GridTrimVertex v ) {
+    if( v.isGridVert() ) {
+      tmeshvert( v.g );
+    } else {
+      tmeshvert( v.t );
+    }
+  }
+  /**
+   * tmeshvert - evaluate a point on a triangle mesh
+   */
+  public void tmeshvert( TrimVertex t ) {
+    long nuid = t.nuid;
+    float u = t.param[0];
+    float v = t.param[1];
+
+    npts++;
+    if( wireframetris ) {
+      if( npts >= 3 ) {
+        surfaceEvaluator.bgnclosedline();
+        if( mesh[0][2] == 0 )
+          surfaceEvaluator.evalcoord2f( mesh[0][3], mesh[0][0], mesh[0][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[0][0], (long) mesh[0][1] );
+        if( mesh[1][2] == 0 )
+          surfaceEvaluator.evalcoord2f( mesh[1][3], mesh[1][0], mesh[1][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[1][0], (long) mesh[1][1] );
+        surfaceEvaluator.evalcoord2f( nuid, u, v );
+        surfaceEvaluator.endclosedline();
+      }
+      mesh[meshindex][0] = u;
+      mesh[meshindex][1] = v;
+      mesh[meshindex][2] = 0;
+      mesh[meshindex][3] = nuid;
+      meshindex = (meshindex+1) % 2;
+    } else {
+      surfaceEvaluator.evalcoord2f( nuid, u, v );
+    }
+  }
+  /**
+   * tmeshvert - evaluate a grid point of a triangle mesh
+   */
+  public void tmeshvert( GridVertex g ) {
+    long u = g->gparam[0];
+    long v = g->gparam[1];
+
+    npts++;
+    if( wireframetris ) {
+      if( npts >= 3 ) {
+        surfaceEvaluator.bgnclosedline();
+        if( mesh[0][2] == 0 )
+          surfaceEvaluator.evalcoord2f( (long) mesh[0][3], mesh[0][0], mesh[0][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[0][0], (long) mesh[0][1] );
+        if( mesh[1][2] == 0 )
+          surfaceEvaluator.evalcoord2f( (long) mesh[1][3], mesh[1][0], mesh[1][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[1][0], (long) mesh[1][1] );
+        surfaceEvaluator.evalpoint2i( u, v );
+        surfaceEvaluator.endclosedline();
+      }
+      mesh[meshindex][0] = u;
+      mesh[meshindex][1] = v;
+      mesh[meshindex][2] = 1;
+      meshindex = (meshindex+1) % 2;
+    } else {
+      surfaceEvaluator.evalpoint2i( u, v );
+    }
+  }
+  /** the same as tmeshvert(trimvertex), for efficiency purpose */
+  public void tmeshvert( float u,  float v ) {
+    long nuid = 0;
+    
+    npts++;
+    if( wireframetris ) {
+      if( npts >= 3 ) {
+        surfaceEvaluator.bgnclosedline();
+        if( mesh[0][2] == 0 )
+          surfaceEvaluator.evalcoord2f( mesh[0][3], mesh[0][0], mesh[0][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[0][0], (long) mesh[0][1] );
+        if( mesh[1][2] == 0 )
+          surfaceEvaluator.evalcoord2f( mesh[1][3], mesh[1][0], mesh[1][1] );
+        else
+          surfaceEvaluator.evalpoint2i( (long) mesh[1][0], (long) mesh[1][1] );
+        surfaceEvaluator.evalcoord2f( nuid, u, v );
+        surfaceEvaluator.endclosedline();
+      }
+      mesh[meshindex][0] = u;
+      mesh[meshindex][1] = v;
+      mesh[meshindex][2] = 0;
+      mesh[meshindex][3] = nuid;
+      meshindex = (meshindex+1) % 2;
+    } else {
+      surfaceEvaluator.evalcoord2f( nuid, u, v );
+    }
+  }
+  /**
+   * linevert - evaluate a point on an outlined contour
+   */
+  public void linevert( TrimVertex t ) {
+    surfaceEvaluator.evalcoord2f( t.nuid, t.param[0], t.param[1] );
+  }
+  /**
+   * linevert - evaluate a grid point of an outlined contour
+   */
+  public void linevert( GridVertex g ) {
+    surfaceEvaluator.evalpoint2i( g.gparam[0], g.gparam[1] );
+  }
+  /**
+   * bgnoutline - preamble to outlined rendering
+   */
+  public void bgnoutline( ) {
+    surfaceEvaluator.bgnline();
+  }
+  /**
+   * endoutline - postamble to outlined rendering
+   */
+  public void endoutline( ) {
+    surfaceEvaluator.endline();
+  }
+  /**
+   * endsurf - postamble to surface
+   */
+  public void endsurf( ) {
+    surfaceEvaluator.endmap2f();
+  }
+  /**
+   * triangle - output a triangle 
+   */
+  public void triangle( TrimVertex a, TrimVertex b, TrimVertex c ) {
+    bgntfan();
+    tmeshvert( a );
+    tmeshvert( b );
+    tmeshvert( c );
+    endtfan();
+  }
+
+  public void bgntfan() {
+    surfaceEvaluator.bgntfan();
+  }
+  public void endtfan() {
+    surfaceEvaluator.endtfan();
+  }
+  public void bgnqstrip() {
+    surfaceEvaluator.bgnqstrip();
+  }
+  public void endqstrip() {
+    surfaceEvaluator.endqstrip();
+  }
+  public void evalUStrip(int n_upper, float v_upper, float[] upper_val,
+                         int n_lower, float v_lower, float[] lower_val) {
+    surfaceEvaluator.evalUStrip(n_upper, v_upper, upper_val, 
+                                n_lower, v_lower, lower_val);
+  }
+  public void evalVStrip(int n_left, float u_left, float[] left_val,
+                         int n_right, float v_right, float[] right_val) {
+    surfaceEvaluator.evalVStrip(n_left, u_left, left_val,
+				n_right, u_right, right_val);
+  }
+  public void tmeshvertNOGE(TrimVertex *t) {
+    // NOTE: under undefined USE_OPTTT #ifdef
+  }
+  public void tmeshvertNOGE_BU(TrimVertex *t) {
+    // NOTE: under undefined USE_OPTTT #ifdef
+  }
+  public void tmeshvertNOGE_BV(TrimVertex *t) {
+    // NOTE: under undefined USE_OPTTT #ifdef
+  }
+  public void preEvaluateBU(float u) {
+    surfaceEvaluator.inPreEvaluateBU_intfac(u);
+  }
+  public void preEvaluateBV(float v) {
+    surfaceEvaluator.inPreEvaluateBV_intfac(v);
+  }
+ 
+  /* curve backend routines */
+  public void bgncurv( void ) {
+    curveEvaluator.bgnmap1f( 0 );
+  }
+  public void segment( float ulo, float uhi ) {
+    curveEvaluator.domain1f( ulo, uhi );
+  }
+  public void curvpts(long type,    /* geometry, color, texture, normal */
+                      float[] pts,  /* control points */
+                      long stride,  /* distance to next point */
+                      int order,    /* parametric order */
+                      float ulo,    /* lower parametric bound */
+                      float uhi )   /* upper parametric bound */ {
+    curveEvaluator.map1f( type, ulo, uhi, stride, order, pts );
+    curveEvaluator.enable( type );
+  }
+  public void curvgrid( float u0, float u1, long nu ) {
+    curveEvaluator.mapgrid1f( nu, u0, u1 );
+  }
+  public void curvmesh( long from, long n ) {
+    curveEvaluator.mapmesh1f( N_MESHFILL, from, from+n );
+  }
+  public void curvpt( float u ) {
+    curveEvaluator.evalcoord1f( 0, u );
+  }
+  public void bgnline( ) {
+    curveEvaluator.bgnline();
+  }
+  public void endline( ) {
+    curveEvaluator.endline();
+  }
+  public void endcurv( ) {
+    curveEvaluator.endmap1f();
+  }
+
+  private boolean  wireframetris;
+  private boolean  wireframequads;
+  private int  npts;
+  private float[][] mesh = new float[3][4];
+  private int  meshindex;
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/BasicCurveEvaluator.java b/src/net/java/games/jogl/impl/nurbs/internals/BasicCurveEvaluator.java
new file mode 100755
index 000000000..3aae3674b
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/BasicCurveEvaluator.java
@@ -0,0 +1,50 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class BasicCurveEvaluator extends CachingEvaluator {
+  public void domain1f(float ulo, float uhi)               {}
+  public void range1f(long type, float[] from, float[] to) {}
+
+  public void enable(long type)                            {}
+  public void disable(long type)                           {}
+  public void bgnmap1f(long type)                          {}
+  public void map1f(long type, float ulo, float uhi, long stride, long order, float[] pts) {}
+  public void mapgrid1f(long nu, float u0, float u1)       {}
+  public void mapmesh1f(long style, long from, long to)    {}
+  public void evalcoord1f(long type, float u)              {}
+  public void endmap1f()                                   {}
+
+  public void bgnline()                                    {}
+  public void endline()                                    {}
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/BasicSurfaceEvaluator.java b/src/net/java/games/jogl/impl/nurbs/internals/BasicSurfaceEvaluator.java
new file mode 100755
index 000000000..f2b4a6679
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/BasicSurfaceEvaluator.java
@@ -0,0 +1,76 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public abstract class BasicSurfaceEvaluator extends CachingEvaluator {
+  public void range2f(long, float[] from, float[] to)              {}
+  public void domain2f(float ulo, float uhi, float vlo, float vhi) {}
+
+  public void enable(long type)                                    {}
+  public void disable(long type)                                   {}
+  public void bgnmap2f(long type)                                  {}
+  public void map2f(long type, float ulower, float uupper, long ustride, long uorder, 
+                    float vlower, float vupper, long vstride, long vorder, 
+                    float[] pts)                                   {}
+  public void mapgrid2f(long nu, float u0, float u1,
+                        long nv, float v0, float v1)               {}
+  public void mapmesh2f(long style, long umin, long umax,
+                        long vmin, long vmax)                      {}
+  public void evalcoord2f(long type, float u, float v)             {}
+  public void evalpoint2i(long u, long v)                          {}
+  public void endmap2f()                                           {}
+
+  public void polymode(long style)                                 {}
+  public void bgnline()                                            {}
+  public void endline()                                            {}
+  public void bgnclosedline()                                      {}
+  public void endclosedline()                                      {}
+  public void bgntmesh()                                           {}
+  public void swaptmesh()                                          {}
+  public void endtmesh()                                           {}
+  public void bgnqstrip()                                          {}
+  public void endqstrip()                                          {}
+
+  public void bgntfan()                                            {}
+  public void endtfan()                                            {}
+
+  public abstract void evalUStrip(int n_upper, float v_upper, float[] upper_val,
+                                  int n_lower, float v_lower, float[] lower_val);
+  public abstract void evalVStrip(int n_left, float u_left, float[] left_val,
+                                  int n_right, float u_right, float[] right_val);
+  public abstract void inDoEvalCoord2NOGE(float u, float v, float[] ret_point, float[] ret_normal);
+  public abstract void inDoEvalCoord2NOGE_BU(float u, float v, float[] ret_point, float[] ret_normal);
+  public abstract void inDoEvalCoord2NOGE_BV(float u, float v, float[] ret_point, float[] ret_normal);
+  public abstract void inPreEvaluateBV_intfac(float v);
+  public abstract void inPreEvaluateBU_intfac(float u);
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/BezierArc.java b/src/net/java/games/jogl/impl/nurbs/internals/BezierArc.java
new file mode 100755
index 000000000..feac7d544
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/BezierArc.java
@@ -0,0 +1,42 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+/** A bezier arc. */
+class BezierArc {
+  public float[]  cpts;    /* control points of arc */
+  public int      order;   /* order of arc */
+  public int      stride;  /* REAL distance between points */
+  public long     type;    /* curve type */
+  public Mapdesc  mapdesc;
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/Bin.java b/src/net/java/games/jogl/impl/nurbs/internals/Bin.java
new file mode 100755
index 000000000..55bec5eae
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/Bin.java
@@ -0,0 +1,147 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class Bin {
+  private Arc head;    /*first arc on list */
+  private Arc current; /* current arc on list */
+
+  /**
+   * Sets current arc to first arc of bin; advances to next arc.
+   */
+  public Arc firstarc( ) {
+    current = head;
+    return nextarc( );
+  }
+  /**
+   * Returns current arc in bin and advances pointer to next arc.
+   */
+  public Arc nextarc( ) {
+    Arc jarc = current;
+
+    assert( (jarc == null) || jarc.check() );
+
+    if( jarc != null ) current = jarc.link;
+    return jarc;
+  }
+  /**
+   * Removes first Arc from bin.
+   */
+  public Arc removearc( ) {
+    Arc jarc = head;
+
+    if( jarc != null ) head = jarc.link;
+    return jarc;
+  }
+  public boolean isnonempty( ) { return (head != null); }
+  /**
+   * Adds an Arc to head of the linked list of Arcs.
+   */
+  public void addarc( Arc jarc ) {
+    jarc.link = head;
+    head = jarc;
+  }
+  /**
+   * Removes given Arc from bin.
+   */
+  public void  remove_this_arc( Arc arc ) {
+    Arc j, prev;
+    for( j = head; (j != null) && (j != arc); prev = j, j = j.link );
+
+    if( j != null ) {
+      if( j == current )
+        current = j.link;
+      if ( prev != null )
+        prev.link = j.link;
+    }
+  }
+  /**
+   * Counts number of arcs in bin.
+   */
+  public int numarcs( ) {
+    long count = 0;
+    for( Arc jarc = firstarc(); jarc != null; jarc = nextarc() )
+	count++;
+    return count;
+  }
+  /**
+   * Places an orphaned arc into its new parent's bin.
+   */
+  public void adopt( ) {
+    markall();
+
+    Arc orphan;
+    while( (orphan = removearc()) != null ) {
+      for( Arc parent = orphan.next; parent != orphan; parent = parent.next ) {
+        if (! parent.ismarked() ) {
+          orphan.link = parent.link;
+          parent.link = orphan;
+          orphan.clearmark();
+          break;
+        }
+      }
+    }
+  }
+  /**
+   * Marks all arcs with an identifying tag.
+   */
+  public void markall( ) {
+    for( Arc jarc = firstarc(); jarc != null; jarc = nextarc() )
+      jarc.setmark();
+  }
+  /**
+   * Prints out descriptions of the arcs in the bin.
+   */
+  public void show( String name ) {
+    System.out.println( name );
+    for( Arc jarc = firstarc(); jarc != null; jarc = nextarc() )
+        jarc.show( );
+  }
+  /**
+   * Prints out all arcs that are untessellated border arcs.
+   */
+  public void listBezier( ) {
+    for( Arc jarc = firstarc(); jarc != null; jarc = nextarc() ) {
+      if( jarc.isbezier( ) ) {
+        assert( jarc.pwlArc.npts == 2 );	
+        TrimVertex[] pts = jarc.pwlArc.pts;
+        float s1 = pts[0].param[0];
+        float t1 = pts[0].param[1];
+        float s2 = pts[1].param[0];
+        float t2 = pts[1].param[1];
+        System.out.println( "arc ( " + s1 + "," + t1 + ") (" +
+                            s2 + "," + t2 + ")");
+      }
+    }
+  }
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/CachingEvaluator.java b/src/net/java/games/jogl/impl/nurbs/internals/CachingEvaluator.java
new file mode 100755
index 000000000..c9c8c5cf9
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/CachingEvaluator.java
@@ -0,0 +1,56 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class CachingEvaluator {
+  public int ServiceModePlay          = 0;
+  public int ServiceModeRecord        = 1;
+  public int ServiceModePlayAndRecord = 2;
+
+  public int canRecord() {
+    return 0;
+  }
+
+  public int canPlayAndRecord() {
+    return 0;
+  }
+
+  public int createHandle( int handle ) {
+    return 0;
+  }
+
+  public void beginOutput( int serviceMode, int handle ) {}
+  public void endOutput()                                {}
+  public void discardRecording(int handle)               {}
+  public void playRecording(int handle)                  {}
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/Defines.java b/src/net/java/games/jogl/impl/nurbs/internals/Defines.java
new file mode 100755
index 000000000..fc284abbd
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/Defines.java
@@ -0,0 +1,46 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class Defines {
+  /* culling constants */
+  public static final int CULL_TRIVIAL_REJECT = 0;
+  public static final int CULL_TRIVIAL_ACCEPT = 1;
+  public static final int CULL_ACCEPT         = 2;
+
+  /* maximum order of a B-Spline */ 
+  public static final int MAXORDER = 24;
+
+  /* maximum dimension of any B-spline range space  */
+  public static final int MAXCOORDS = 5;
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/NurbsConsts.java b/src/net/java/games/jogl/impl/nurbs/internals/NurbsConsts.java
new file mode 100755
index 000000000..74c9c150c
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/NurbsConsts.java
@@ -0,0 +1,117 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class NurbsConsts {
+  /* NURBS Properties - one set per map, 
+     each takes a single INREAL arg */
+  public static final int N_SAMPLING_TOLERANCE = 1;
+  public static final int N_S_RATE = 6;
+  public static final int N_T_RATE = 7;
+  public static final int N_CLAMPFACTOR = 13;
+  public static final float N_NOCLAMPING = 0.0f;
+  public static final int N_MINSAVINGS = 14;
+  public static final float N_NOSAVINGSSUBDIVISION = 0.0f;
+
+  /* NURBS Properties - one set per map, 
+     each takes an enumerated value */
+  public static final int N_CULLING = 2;
+  public static final float N_NOCULLING = 0.0f;
+  public static final float N_CULLINGON = 1.0f;
+  public static final int N_SAMPLINGMETHOD 10;
+  public static final float N_NOSAMPLING = 0.0f;
+  public static final float N_FIXEDRATE = 3.0f;
+  public static final float N_DOMAINDISTANCE = 2.0f;
+  public static final float N_PARAMETRICDISTANCE = 5.0f;
+  public static final float N_PATHLENGTH = 6.0f;
+  public static final float N_SURFACEAREA = 7.0f;
+  public static final float N_OBJECTSPACE_PARA = 8.0f;
+  public static final float N_OBJECTSPACE_PATH = 9.0f;
+  public static final int N_BBOX_SUBDIVIDING = 17;
+  public static final float N_NOBBOXSUBDIVISION = 0.0f;
+  public static final float N_BBOXTIGHT = 1.0f;
+  public static final float N_BBOXROUND = 2.0f;
+
+  /* NURBS Rendering Properties - one set per renderer
+     each takes an enumerated value */
+public static final int N_DISPLAY  3
+public static final int  N_FILL   1.0  
+public static final int  N_OUTLINE_POLY  2.0
+public static final int  N_OUTLINE_TRI  3.0
+public static final int  N_OUTLINE_QUAD   4.0
+public static final int  N_OUTLINE_PATCH  5.0
+public static final int  N_OUTLINE_PARAM  6.0
+public static final int  N_OUTLINE_PARAM_S 7.0
+public static final int  N_OUTLINE_PARAM_ST  8.0
+public static final int  N_OUTLINE_SUBDIV  9.0
+public static final int  N_OUTLINE_SUBDIV_S  10.0
+public static final int  N_OUTLINE_SUBDIV_ST  11.0
+public static final int  N_ISOLINE_S  12.0
+public static final int N_ERRORCHECKING  4
+public static final int  N_NOMSG   0.0
+public static final int  N_MSG   1.0
+
+/* GL 4.0 propeties not defined above */
+#ifndef N_PIXEL_TOLERANCE
+public static final int N_PIXEL_TOLERANCE N_SAMPLING_TOLERANCE
+public static final int N_ERROR_TOLERANCE 20
+public static final int N_SUBDIVISIONS  5
+public static final int N_TILES   8
+public static final int N_TMP1   9
+public static final int N_TMP2   N_SAMPLINGMETHOD
+public static final int N_TMP3   11
+public static final int N_TMP4   12
+public static final int N_TMP5   N_CLAMPFACTOR
+public static final int N_TMP6   N_MINSAVINGS
+public static final int N_S_STEPS  N_S_RATE
+public static final int N_T_STEPS  N_T_RATE
+#endif
+
+/* NURBS Rendering Properties - one set per map,
+   each takes an INREAL matrix argument */
+public static final int N_CULLINGMATRIX  1
+public static final int N_SAMPLINGMATRIX 2
+public static final int N_BBOXMATRIX  3
+
+
+/* NURBS Rendering Properties - one set per map,
+   each takes an INREAL vector argument */
+public static final int N_BBOXSIZE  4
+
+/* type argument for trimming curves */
+#ifndef N_P2D
+public static final int N_P2D     0x8 
+public static final int N_P2DR     0xd
+#endif 
+  
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/NurbsException.java b/src/net/java/games/jogl/impl/nurbs/internals/NurbsException.java
new file mode 100755
index 000000000..5453807cd
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/NurbsException.java
@@ -0,0 +1,30 @@
+/** Encapsulates functionality of the C GLU NURBS implementation's
+    setjmp/longjmp wrappers. */
+
+public class NurbsException extends RuntimeException {
+  private int errorCode;
+  
+  public NurbsException(int code) {
+    super();
+    errorCode = code;
+  }
+
+  public NurbsException(String message, int code) {
+    super(message);
+    errorCode = code;
+  }
+
+  public NurbsException(String message, Throwable cause, int code) {
+    super(message, cause);
+    errorCode = code;
+  }
+
+  public NurbsException(Throwable cause, int code) {
+    super(cause);
+    errorCode = code;
+  }
+
+  public int errorCode() {
+    return errorCode;
+  }
+}
diff --git a/src/net/java/games/jogl/impl/nurbs/internals/Subdivider.java b/src/net/java/games/jogl/impl/nurbs/internals/Subdivider.java
new file mode 100755
index 000000000..155b6b7ac
--- /dev/null
+++ b/src/net/java/games/jogl/impl/nurbs/internals/Subdivider.java
@@ -0,0 +1,1781 @@
+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+public class Subdivider {
+
+  /**
+   * Constructs a subdivider.
+   */
+  public Subdivider(RenderHints hints, Backend b) {
+    renderhints = hints;
+    arctessellator = new ArcTesselator();
+    backend = b;
+    slicer = new Slicer(b);
+  }
+
+  /**
+   * Resets all state after possible error condition.
+   */
+  public void clear() {
+    // FIXME: looks like nothing to do given that we have no object pools
+  }
+  public void beginTrims() {}
+  public void beginLoop() {
+    pjarc = 0;
+  }
+
+  /**
+   * Adds a bezier arc to a trim loop and to a bin.
+   */
+  public void addArc(float[] cpts, Quilt quilt, long _nuid) {
+    BezierArc bezierArc = new BezierArc();
+    Arc jarc = new Arc(Arc.SIDE_NONE, _nuid);
+    jarc.bezierArc = bezierArc;
+    bezierArc.order = quilt.qspec.order;
+    bezierArc.stride = quilt.qspec.stride;
+    bezierArc.mapdesc = quilt.mapdesc;
+    bezierArc.cpts = cpts;
+    initialbin.addarc( jarc );
+    pjarc = jarc.append( pjarc );
+  }
+
+  /**
+   * Adds a pwl arc to a trim loop and to a bin.
+   */
+  public void addArc(int npts, TrimVertex[] pts, long _nuid) {
+    Arc jarc = new Arc( Arc.SIDE_NONE, _nuid );
+    jarc.pwlArc = new PwlArc( npts, pts );        
+    initialbin.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+  }
+  public void endLoop() {}
+  public void endTrims() {}
+
+  public void beginQuilts() {
+    qlist = null;
+  }
+  public void addQuilt( Quilt quilt ) {
+    quilt.next = qlist;
+    qlist = quilt;
+  }
+  public void endQuilts() {}
+
+  /**
+   * Main curve rendering entry point
+   */
+  public void drawCurves() {
+    float[] from = new float[1];
+    float[] to   = new float[1];
+    Flist bpts = new Flist();
+    qlist.getRange( from, to, bpts );
+
+    renderhints.init( );
+
+    backend.bgncurv();
+    float[] pta = new float[0];
+    float[] ptb = new float[1];
+    for( int i=bpts.start; i<bpts.end-1; i++ ) {
+      pta[0] = bpts.pts[i];
+      ptb[0] = bpts.pts[i+1];
+
+      qlist.downloadAll( pta, ptb, backend );
+
+      Curvelist curvelist = new Curvelist( qlist, pta, ptb );
+      samplingSplit( curvelist, renderhints.maxsubdivisions );
+    }
+    backend.endcurv();
+  }
+  public void drawSurfaces(long nuid) {
+    renderhints.init( );
+
+    if (qlist == null) {
+      //initialbin could be nonempty due to some errors
+      freejarcs(initialbin);
+      return;
+    }
+
+    for( Quilt q = qlist; q != null; q = q.next ) {
+      if( q.isCulled( ) == Defines.CULL_TRIVIAL_REJECT ) {
+        freejarcs( initialbin );
+        return;
+      }
+    }
+
+
+    float[] from = new float[2];
+    float[] to   = new float[2];
+    qlist.getRange( from, to, spbrkpts, tpbrkpts );
+    //perform optimization only when the samplng method is 
+    //DOMAIN_DISTANCE and the display methdo is either 
+    //fill or outline_polygon.
+    bool optimize = (is_domain_distance_sampling && (renderhints.display_method != N_OUTLINE_PATCH));
+
+    if( ! initialbin.isnonempty() ) {
+      if(! optimize )
+        {  
+          makeBorderTrim( from, to );
+        }
+    } else {
+      float[] rate = new float[2];
+      qlist.findRates( spbrkpts, tpbrkpts, rate );
+
+      if( decompose( initialbin, Math.min(rate[0], rate[1]) ) ) 
+        throw new NurbsException( 31 );
+    }
+
+    backend.bgnsurf( renderhints.wiretris, renderhints.wirequads, nuid );
+
+    if( (!initialbin.isnonempty())  && optimize )
+      {
+        int i,j;
+        int num_u_steps;
+        int num_v_steps;
+        for(i=spbrkpts.start; i<spbrkpts.end-1; i++){
+          for(j=tpbrkpts.start; j<tpbrkpts.end-1; j++){
+            float[] pta = new float[2];
+            float[] ptb = new float[2];
+            pta[0] = spbrkpts.pts[i];
+            ptb[0] = spbrkpts.pts[i+1];
+            pta[1] = tpbrkpts.pts[j];
+            ptb[1] = tpbrkpts.pts[j+1];
+            qlist.downloadAll(pta, ptb, backend);
+     
+            num_u_steps = (int) (domain_distance_u_rate * (ptb[0]-pta[0]));
+            num_v_steps = (int) (domain_distance_v_rate * (ptb[1]-pta[1]));
+
+            if(num_u_steps <= 0) num_u_steps = 1;
+            if(num_v_steps <= 0) num_v_steps = 1;
+
+            backend.surfgrid(pta[0], ptb[0], num_u_steps, 
+                             ptb[1], pta[1], num_v_steps);
+            backend.surfmesh(0,0,num_u_steps,num_v_steps);
+
+            continue;
+          }
+        }
+      }
+    else
+      subdivideInS( initialbin );
+
+    backend.endsurf();
+  }
+
+  public int ccwTurn_sl(Arc j1, Arc j2 ) {
+    int v1i             = j1.pwlArc.npts-1;
+    int v1lasti         = 0;
+    int v2i             = 0;
+    int v2lasti         = j2.pwlArc.npts-1;
+    int v1nexti         = v1i-1;
+    int v2nexti         = v2i+1;
+    TrimVertex v1       = j1.pwlArc.pts[v1i];
+    TrimVertex v1last   = j1.pwlArc.pts[v1lasti];
+    TrimVertex v2       = j2.pwlArc.pts[v2i];
+    TrimVertex v2last   = j2.pwlArc.pts[v2lasti];
+    TrimVertex v1next   = j1.pwlArc.pts[v1nexti];
+    TrimVertex v2next   = j2.pwlArc.pts[v2nexti];
+    int sgn;
+
+    assert( v1 != v1last );
+    assert( v2 != v2last );
+
+    // the arcs lie on the line (0 == v1.param[0])
+    if( v1.param[0] == v1next.param[0] && v2.param[0] == v2next.param[0] )
+      return 0;
+
+    if( v2next.param[0] > v2.param[0] || v1next.param[0] > v1.param[0] ) 
+      throw new NurbsException(28);
+
+    if( v1.param[1] < v2.param[1] )
+      return 1;
+    else if( v1.param[1] > v2.param[1] )
+      return 0;
+
+    while( true ) {
+      if( v1next.param[0] > v2next.param[0] ) {
+        assert( v1.param[0] >= v1next.param[0] );
+        assert( v2.param[0] >= v1next.param[0] );
+        switch( bbox( v2next, v2, v1next, 1 ) ) {
+        case -1:
+          return 1;
+        case 0:
+          sgn = ccw( v1next, v2, v2next );
+          if( sgn != -1 ) 
+            return sgn;
+          else {
+            v1i = v1nexti--;
+            v1 = j1.pwlArc.pts[v1i];
+            v1next = j1.pwlArc.pts[v1nexti];
+            if( v1 == v1last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 0;
+        }
+      } else if( v1next.param[0] < v2next.param[0] ) {
+        assert( v1.param[0] >= v2next.param[0] );
+        assert( v2.param[0] >= v2next.param[0] );
+        switch( bbox( v1next, v1, v2next, 1 ) ) {
+        case -1:
+          return 0;
+        case 0:
+          sgn = ccw( v1next, v1, v2next );
+          if( sgn != -1 ) 
+            return sgn;
+          else {
+            v2i = v2nexti++;
+            v2 = j2.pwlArc.pts[v2i];
+            v2next = j2.pwlArc.pts[v2nexti];
+            if( v2 == v2last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 1;
+        }
+      } else {
+        if( v1next.param[1] < v2next.param[1] )
+          return 1;
+        else if( v1next.param[1] > v2next.param[1] )
+          return 0;
+        else {
+          v2i = v2nexti++;
+          v2 = j2.pwlArc.pts[v2i];
+          v2next = j2.pwlArc.pts[v2nexti];
+          if( v2 == v2last ) {
+            return 0; // ill-conditioned, guess answer
+          }
+        }
+      }
+    }
+  }
+
+  public int ccwTurn_sr(Arc j1, Arc j2 ) {
+    // dir = 1
+    int v1i             = j1.pwlArc.npts-1;
+    int v1lasti         = 0;
+    int v2i             = 0;
+    int v2lasti         = j2.pwlArc.npts-1;
+    int v1nexti         = v1i-1;
+    int v2nexti         = v2i+1;
+    TrimVertex v1       = j1.pwlArc.pts[v1i];
+    TrimVertex v1last   = j1.pwlArc.pts[v1lasti];
+    TrimVertex v2       = j2.pwlArc.pts[v2i];
+    TrimVertex v2last   = j2.pwlArc.pts[v2lasti];
+    TrimVertex v1next   = j1.pwlArc.pts[v1nexti];
+    TrimVertex v2next   = j2.pwlArc.pts[v2nexti];
+    int sgn;
+
+    assert( v1 != v1last );
+    assert( v2 != v2last );
+
+    // the arcs lie on the line (0 == v1.param[0])
+    if( v1.param[0] == v1next.param[0] && v2.param[0] == v2next.param[0] )
+      return 0;
+
+    if( v2next.param[0] < v2.param[0] || v1next.param[0] < v1.param[0] )
+      throw new NurbsException(28);
+
+    if( v1.param[1] < v2.param[1] )
+      return 0;
+    else if( v1.param[1] > v2.param[1] )
+      return 1;
+
+    while( true ) {
+      if( v1next.param[0] < v2next.param[0] ) {
+        assert( v1.param[0] <= v1next.param[0] );
+        assert( v2.param[0] <= v1next.param[0] );
+        switch( bbox( v2, v2next, v1next, 1 ) ) {
+        case -1:
+          return 0;
+        case 0:
+          sgn = ccw( v1next, v2, v2next );
+          if( sgn != -1 ) {
+            return sgn;
+          } else {
+            v1i = v1nexti--;
+            v1 = j1.pwlArc.pts[v1i];
+            v1next = j1.pwlArc.pts[v1nexti];
+            if( v1 == v1last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 1;
+        }
+      } else if( v1next.param[0] > v2next.param[0] ) {
+        assert( v1.param[0] <= v2next.param[0] );
+        assert( v2.param[0] <= v2next.param[0] );
+        switch( bbox( v1, v1next, v2next, 1 ) ) {
+        case -1:
+          return 1;
+        case 0:
+          sgn = ccw( v1next, v1, v2next );
+          if( sgn != -1 ) { 
+            return sgn;
+          } else {
+            v2i = v2nexti++;
+            v2 = j2.pwlArc.pts[v2i];
+            v2next = j2.pwlArc.pts[v2nexti];
+            if( v2 == v2last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 0;
+        }
+      } else {
+        if( v1next.param[1] < v2next.param[1] )
+          return 0;
+        else if( v1next.param[1] > v2next.param[1] )
+          return 1;
+        else {
+          v2i = v2nexti++;
+          v2 = j2.pwlArc.pts[v2i];
+          v2next = j2.pwlArc.pts[v2nexti];
+          if( v2 == v2last ) {
+            return 0; // ill-conditioned, guess answer
+          }
+        }
+      }
+    }
+  }
+
+  public int ccwTurn_tl(Arc j1, Arc j2 ) {
+    int v1i             = j1.pwlArc.npts-1;
+    int v1lasti         = 0;
+    int v2i             = 0;
+    int v2lasti         = j2.pwlArc.npts-1;
+    int v1nexti         = v1i-1;
+    int v2nexti         = v2i+1;
+    TrimVertex v1       = j1.pwlArc.pts[v1i];
+    TrimVertex v1last   = j1.pwlArc.pts[v1lasti];
+    TrimVertex v2       = j2.pwlArc.pts[v2i];
+    TrimVertex v2last   = j2.pwlArc.pts[v2lasti];
+    TrimVertex v1next   = j1.pwlArc.pts[v1nexti];
+    TrimVertex v2next   = j2.pwlArc.pts[v2nexti];
+    int sgn;
+
+    assert( v1 != v1last );
+    assert( v2 != v2last );
+
+    // the arcs lie on the line (1 == v1.param[1])
+    if( v1.param[1] == v1next.param[1] && v2.param[1] == v2next.param[1] )
+      return 0;
+
+    if( v2next.param[1] > v2.param[1] || v1next.param[1] > v1.param[1] ) 
+      throw new NurbsException(28 );
+
+    if( v1.param[0] < v2.param[0] )
+      return 0;
+    else if( v1.param[0] > v2.param[0] )
+      return 1;
+
+    while( true ) {
+      if( v1next.param[1] > v2next.param[1] ) {
+        assert( v1.param[1] >= v1next.param[1] );
+        assert( v2.param[1] >= v1next.param[1] );
+        switch( bbox( v2next, v2, v1next, 0 ) ) {
+        case -1:
+          return 0;
+        case 0:
+          sgn = ccw( v1next, v2, v2next );
+          if( sgn != -1 ) 
+            return sgn;
+          else {
+            v1i = v1nexti--;
+            v1 = j1.pwlArc.pts[v1i];
+            v1next = j1.pwlArc.pts[v1nexti];
+            if( v1 == v1last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 1;
+        }
+      } else if( v1next.param[1] < v2next.param[1] ) {
+        switch( bbox( v1next, v1, v2next, 0 ) ) {
+        case -1:
+          return 1;
+        case 0:
+          sgn = ccw( v1next, v1, v2next );
+          if( sgn != -1 ) 
+            return sgn;
+          else {
+            v2i = v2nexti++;
+            v2 = j2.pwlArc.pts[v2i];
+            v2next = j2.pwlArc.pts[v2nexti];
+            if( v2 == v2last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 0;
+        }
+      } else {
+        if( v1next.param[0] < v2next.param[0] )
+          return 0;
+        else if( v1next.param[0] > v2next.param[0] )
+          return 1;
+        else {
+          v2i = v2nexti++;
+          v2 = j2.pwlArc.pts[v2i];
+          v2next = j2.pwlArc.pts[v2nexti];
+          if( v2 == v2last ) {
+            return 0; // ill-conditioned, guess answer
+          }
+        }
+      }
+    }
+  }
+
+  public int ccwTurn_tr(Arc j1, Arc j2) {
+    int v1i             = j1.pwlArc.npts-1;
+    int v1lasti         = 0;
+    int v2i             = 0;
+    int v2lasti         = j2.pwlArc.npts-1;
+    int v1nexti         = v1i-1;
+    int v2nexti         = v2i+1;
+    TrimVertex v1       = j1.pwlArc.pts[v1i];
+    TrimVertex v1last   = j1.pwlArc.pts[v1lasti];
+    TrimVertex v2       = j2.pwlArc.pts[v2i];
+    TrimVertex v2last   = j2.pwlArc.pts[v2lasti];
+    TrimVertex v1next   = j1.pwlArc.pts[v1nexti];
+    TrimVertex v2next   = j2.pwlArc.pts[v2nexti];
+    int sgn;
+
+    assert( v1 != v1last );
+    assert( v2 != v2last );
+
+    // the arcs lie on the line (1 == v1.param[1])
+    if( v1.param[1] == v1next.param[1] && v2.param[1] == v2next.param[1] )
+      return 0;
+
+    if( v2next.param[1] < v2.param[1] || v1next.param[1] < v1.param[1] )
+      throw new NurbsException( 28 );
+
+    if( v1.param[0] < v2.param[0] )
+      return 1;
+    else if( v1.param[0] > v2.param[0] )
+      return 0;
+
+    while( 1 ) {
+      if( v1next.param[1] < v2next.param[1] ) {
+        assert( v1.param[1] <= v1next.param[1] );
+        assert( v2.param[1] <= v1next.param[1] );
+        switch( bbox( v2, v2next, v1next, 0 ) ) {
+        case -1:
+          return 1;
+        case 0:
+          sgn = ccw( v1next, v2, v2next );
+          if( sgn != -1 ) {
+            return sgn;
+          } else {
+            v1i = v1nexti--;
+            v1 = j1.pwlArc.pts[v1i];
+            v1next = j1.pwlArc.pts[v1nexti];
+            if( v1 == v1last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 0;
+        }
+      } else if( v1next.param[1] > v2next.param[1] ) {
+        assert( v1.param[1] <= v2next.param[1] );
+        assert( v2.param[1] <= v2next.param[1] );
+        switch( bbox( v1, v1next, v2next, 0 ) ) {
+        case -1:
+          return 0;
+        case 0:
+          sgn = ccw( v1next, v1, v2next );
+          if( sgn != -1 ) { 
+            return sgn;
+          } else {
+            v2i = v2nexti++;
+            v2 = j2.pwlArc.pts[v2i];
+            v2next = j2.pwlArc.pts[v2nexti];
+            if( v2 == v2last ) {
+              return 0; // ill-conditioned, guess answer
+            }
+          }
+          break;
+        case 1:
+          return 1;
+        }
+      } else {
+        if( v1next.param[0] < v2next.param[0] )
+          return 1;
+        else if( v1next.param[0] > v2next.param[0] )
+          return 0;
+        else {
+          v2i = v2nexti++;
+          v2 = j2.pwlArc.pts[v2i];
+          v2next = j2.pwlArc.pts[v2nexti];
+          if( v2 == v2last ) {
+            return 0; // ill-conditioned, guess answer
+          }
+        }
+      }
+    }
+  }
+
+  public void set_domain_distance_u_rate(float u_rate) {
+    domain_distance_u_rate = u_rate;
+  }
+
+  public void set_domain_distance_v_rate(float v_rate) {
+    domain_distance_v_rate = v_rate;
+  }
+
+  public void set_is_domain_distance_sampling(int flag) {
+    is_domain_distance_sampling = flag;
+  }
+
+  //----------------------------------------------------------------------
+  // Internals only below this point
+  //
+
+  /**
+   * Determine which side of a line a jarc lies (for debugging only)
+   */
+  private int arc_classify( Arc jarc, int param, float value )
+  {
+    float tdiff, hdiff;
+    if( param == 0 ) {
+      tdiff = jarc.tail()[0] - value;
+      hdiff = jarc.head()[0] - value;
+    } else {
+      tdiff = jarc.tail()[1] - value;
+      hdiff = jarc.head()[1] - value;
+    }
+
+    if( tdiff > 0.0 ) {
+      if( hdiff > 0.0 ) {
+        return 0x11;
+      } else if( hdiff == 0.0 ) {
+        return 0x12;
+      } else {
+        return 0x10;
+      }
+    } else if( tdiff == 0.0 ) {
+      if( hdiff > 0.0 ) {
+        return 0x21;
+      } else if( hdiff == 0.0 ) {
+        return 0x22;
+      } else {
+        return 0x20;
+      }
+    } else {
+      if( hdiff > 0.0 ) {
+        return 0x01;
+      } else if( hdiff == 0.0 ) {
+        return 0x02;
+      } else {
+        return 0;
+      }
+    }
+  }
+
+  private void classify_headonleft_s( Bin bin, Bin in, Bin out, float val ) {
+    /* tail on line, head at left */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 0, val ) == 0x20 );
+
+      j.setitail();
+
+      float diff = j.prev.tail()[0] - val;
+      if( diff > 0.0 ) {
+        out.addarc( j );
+      } else if( diff < 0.0 ) {
+        if( ccwTurn_sl( j.prev, j ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else {
+        if( j.prev.tail()[1] > j.prev.head()[1] )
+          in.addarc( j );
+        else
+          out.addarc( j );
+      }
+    }
+  }
+
+  private void classify_tailonleft_s( Bin bin, Bin in, Bin out, float val ) {
+    /* tail at left, head on line */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 1, val ) == 0x02 );
+      j.clearitail();
+
+      float diff = j.next.head()[1] - val;
+      if( diff > 0.0 ) {
+        in.addarc( j );
+      } else if( diff < 0.0 ) {
+        if( ccwTurn_tl( j, j.next ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else {
+        if (j.next.tail()[0] > j.next.head()[0] )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      }
+    }
+  }
+
+  private void classify_headonright_s( Bin bin, Bin in, Bin out, float val ) {
+    /* tail on line, head at right */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 0, val ) == 0x21 );
+    
+      j.setitail();
+
+      float diff = j.prev.tail()[0] - val;
+      if( diff > 0.0 ) { 
+        if( ccwTurn_sr( j.prev, j ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else if( diff < 0.0 ) {
+        out.addarc( j );
+      } else {
+        if( j.prev.tail()[1] > j.prev.head()[1] )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      }
+    }
+  }
+
+  private void classify_tailonright_s( Bin bin, Bin in, Bin out, float val ) {
+    /* tail at right, head on line */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 0, val ) == 0x12);
+	
+      j.clearitail();
+
+      float diff = j.next.head()[0] - val;
+      if( diff > 0.0 ) {
+        if( ccwTurn_sr( j, j.next ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else if( diff < 0.0 ) {
+        in.addarc( j );
+      } else {
+        if( j.next.tail()[1] > j.next.head()[1] ) 
+          out.addarc( j );
+        else
+          in.addarc( j );
+      }
+    }
+  }
+
+  private void classify_headonleft_t( Bin bin, Bin in, Bin out, float val ) {
+    /* tail on line, head at left */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 1, val ) == 0x20 );
+      j.setitail();
+
+      float diff = j.prev.tail()[1] - val;
+      if( diff > 0.0 ) {
+        out.addarc( j );
+      } else if( diff < 0.0 ) {
+        if( ccwTurn_tl( j.prev, j ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else {
+        if( j.prev.tail()[0] > j.prev.head()[0] )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      }
+    }
+  }
+
+  private void classify_tailonleft_t( Bin bin, Bin in, Bin out, float val ) {
+    /* tail at left, head on line */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 1, val ) == 0x02 );
+      j.clearitail();
+
+      float diff = j.next.head()[1] - val;
+      if( diff > 0.0 ) {
+        in.addarc( j );
+      } else if( diff < 0.0 ) {
+        if( ccwTurn_tl( j, j.next ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else {
+        if (j.next.tail()[0] > j.next.head()[0] )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      }
+    }
+  }
+
+  private void classify_headonright_t( Bin bin, Bin in, Bin out, float val ) {
+    /* tail on line, head at right */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 1, val ) == 0x21 );
+    
+      j.setitail();
+
+      float diff = j.prev.tail()[1] - val;
+      if( diff > 0.0 ) { 
+        if( ccwTurn_tr( j.prev, j ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else if( diff < 0.0 ) {
+        out.addarc( j );
+      } else {
+        if( j.prev.tail()[0] > j.prev.head()[0] )
+          in.addarc( j );
+        else
+          out.addarc( j );
+      }
+    }
+  }
+
+  private void classify_tailonright_t( Bin bin, Bin in, Bin out, float val ) {
+    /* tail at right, head on line */
+    Arc j;
+
+    while( (j = bin.removearc()) != null ) {
+      assert( arc_classify( j, 1, val ) == 0x12);
+	
+      j.clearitail();
+
+      float diff =  j.next.head()[1] - val;
+      if( diff > 0.0 ) {
+        if( ccwTurn_tr( j, j.next ) != 0 )
+          out.addarc( j );
+        else
+          in.addarc( j );
+      } else if( diff < 0.0 ) { 
+        in.addarc( j );
+      } else {
+        if( j.next.tail()[0] > j.next.head()[0] ) 
+          in.addarc( j );
+        else
+          out.addarc( j );
+      }
+    }
+  }
+
+  private int DIR_DOWN = 0;
+  private int DIR_SAME = 1;
+  private int DIR_UP   = 2;
+  private int DIR_NONE = 3;
+
+  private void tessellate( Arc_ptr, float );
+  private void monotonize( Arc_ptr , Bin & );
+  private int isMonotone( Arc_ptr  );
+  private int decompose( Bin &, float );
+
+
+  private Slicer slicer;
+  private ArcTessellator arctessellator;
+  //  private Pool arcpool;
+  //  private Pool bezierarcpool;
+  //  private Pool pwlarcpool;
+  //  private TrimVertexPool trimvertexpool;
+
+  private JumpBuffer* jumpbuffer;
+  private Renderhints& renderhints;
+  private Backend&  backend;
+
+  private Bin initialbin;
+  private Arc pjarc;
+  private int s_index;
+  private int t_index;
+  private Quilt *qlist;
+  private Flist spbrkpts;
+  private Flist tpbrkpts;
+  private Flist smbrkpts;
+  private Flist tmbrkpts;
+  private float stepsizes[4];
+  private int showDegenerate;
+  private int isArcTypeBezier;
+
+  // FIXME: NOT FINISHED
+  private void samplingSplit( Curvelist&, int );
+
+  private void subdivideInS( Bin source ) {
+    if( renderhints.display_method == N_OUTLINE_PARAM ) {
+      outline( source );
+      freejarcs( source );
+    } else {
+      setArcTypeBezier();
+      setNonDegenerate();
+      splitInS( source, spbrkpts.start, spbrkpts.end );
+    }
+  }
+
+  /**
+   * Splits a patch and a bin by an isoparametric line.
+   */
+  private void splitInS( Bin source, int start, int end ) {
+    if( source.isnonempty() ) {
+      if( start != end ) {
+        int  i = start + (end - start) / 2;
+        Bin left = new Bin();
+        Bin right = new Bin();
+        split( source, left, right, 0, spbrkpts.pts[i] );
+        splitInS( left, start, i );
+        splitInS( right, i+1, end );
+      } else {
+        if( start == spbrkpts.start || start == spbrkpts.end ) {
+          freejarcs( source );
+        } else if( renderhints.display_method == NurbsConsts.N_OUTLINE_PARAM_S ) {
+          outline( source );
+          freejarcs( source );
+        } else {
+          setArcTypeBezier();
+          setNonDegenerate();
+          s_index = start;
+          splitInT( source, tpbrkpts.start, tpbrkpts.end );
+        }
+      }
+    } 
+  }
+
+  /**
+   * Splits a patch and a bin by an isoparametric line.
+   */
+  private void splitInT( Bin source, int start, int end ) {
+    if( source.isnonempty() ) {
+      if( start != end ) {
+        int  i = start + (end - start) / 2;
+        Bin left = new Bin();
+        Bin right = new Bin();
+        split( source, left, right, 1, tpbrkpts.pts[i] );
+        splitInT( left, start, i );
+        splitInT( right, i+1, end );
+      } else {
+        if( start == tpbrkpts.start || start == tpbrkpts.end ) {
+          freejarcs( source );
+        } else if( renderhints.display_method == NurbsConsts.N_OUTLINE_PARAM_ST ) {
+          outline( source );
+          freejarcs( source );
+        } else {
+          t_index = start;
+          setArcTypeBezier();
+          setDegenerate();
+
+          float[] pta = new float[2];
+          float[] ptb = new float[2];
+          pta[0] = spbrkpts.pts[s_index-1];
+          pta[1] = tpbrkpts.pts[t_index-1];
+
+          ptb[0] = spbrkpts.pts[s_index];
+          ptb[1] = tpbrkpts.pts[t_index];
+          qlist.downloadAll( pta, ptb, backend );
+      
+          Patchlist patchlist = new Patchlist( qlist, pta, ptb );
+          /*
+            printf("-------samplingSplit-----\n");
+            source.show("samplingSplit source");
+          */
+          samplingSplit( source, patchlist, renderhints.maxsubdivisions, 0 );
+          setNonDegenerate();
+          setArcTypeBezier();
+        }
+      }
+    } 
+  }
+
+  /**
+   * Recursively subdivides patch, cull checks each subpatch  
+   */
+  private void samplingSplit( Bin source, Patchlist patchlist, int subdivisions, int param ) {
+    if( ! source.isnonempty() ) return;
+
+    if( patchlist.cullCheck() == Defines.CULL_TRIVIAL_REJECT ) {
+      freejarcs( source );
+      return;
+    }
+
+    patchlist.getstepsize();
+
+    if( renderhints.display_method == NurbsConsts.N_OUTLINE_PATCH ) {
+      tessellation( source, patchlist );
+      outline( source );
+      freejarcs( source );
+      return;
+    } 
+
+    //patchlist.clamp();
+
+    tessellation( source, patchlist );
+
+    if( patchlist.needsSamplingSubdivision() && (subdivisions > 0) ) {
+      if( ! patchlist.needsSubdivision( 0 ) )
+        param = 1;
+      else if( ! patchlist.needsSubdivision( 1 ) )
+        param = 0;
+      else
+        param = 1 - param;
+
+      Bin left = new Bin();
+      Bin right = new Bin();
+      float mid = ( patchlist.pspec[param].range[0] +
+                   patchlist.pspec[param].range[1] ) * 0.5;
+      split( source, left, right, param, mid );
+      Patchlist subpatchlist = new Patchlist( patchlist, param, mid );
+      samplingSplit( left, subpatchlist, subdivisions-1, param );
+      samplingSplit( right, patchlist, subdivisions-1, param );
+    } else {
+      setArcTypePwl();
+      setDegenerate();
+      nonSamplingSplit( source, patchlist, subdivisions, param );
+      setDegenerate();
+      setArcTypeBezier();
+    }
+  }
+
+  private void nonSamplingSplit( Bin source, Patchlist patchlist, int subdivisions, int param ) {
+    if( patchlist.needsNonSamplingSubdivision() && (subdivisions > 0) ) {
+      param = 1 - param;
+
+      Bin left = new Bin();
+      Bin right = new Bin();
+      float mid = ( patchlist.pspec[param].range[0] +
+                   patchlist.pspec[param].range[1] ) * 0.5;
+      split( source, left, right, param, mid );
+      Patchlist subpatchlist = new Patchlist( patchlist, param, mid );
+      if( left.isnonempty() )
+        if( subpatchlist.cullCheck() == Defines.CULL_TRIVIAL_REJECT ) 
+          freejarcs( left );
+        else
+          nonSamplingSplit( left, subpatchlist, subdivisions-1, param );
+      if( right.isnonempty() ) 
+        if( patchlist.cullCheck() == Defines.CULL_TRIVIAL_REJECT ) 
+          freejarcs( right );
+        else
+          nonSamplingSplit( right, patchlist, subdivisions-1, param );
+
+    } else {
+      // make bbox calls
+      patchlist.bbox();
+      backend.patch( patchlist.pspec[0].range[0], patchlist.pspec[0].range[1],
+                     patchlist.pspec[1].range[0], patchlist.pspec[1].range[1] );
+    
+      if( renderhints.display_method == NurbsConsts.N_OUTLINE_SUBDIV ) {
+        outline( source );
+        freejarcs( source );
+      } else {
+        setArcTypePwl();
+        setDegenerate();
+        findIrregularS( source );
+        monosplitInS( source, smbrkpts.start, smbrkpts.end );
+      }
+    }
+  }
+
+  /**
+   * Sets tessellation of interior and boundary of patch.
+   */
+  private void tessellation( Bin bin, Patchlist patchlist ) {
+    // tessellate unsampled trim curves
+    tessellate( bin, patchlist.pspec[1].sidestep[1], patchlist.pspec[0].sidestep[1],
+                patchlist.pspec[1].sidestep[0], patchlist.pspec[0].sidestep[0] );
+
+    // set interior sampling rates
+    slicer.setstriptessellation( patchlist.pspec[0].stepsize, patchlist.pspec[1].stepsize );
+
+    //added by zl: set the order which will be used in slicer.c++
+    slicer.set_ulinear( (patchlist.get_uorder() == 2));
+    slicer.set_vlinear( (patchlist.get_vorder() == 2));
+
+    // set boundary sampling rates
+    stepsizes[0] = patchlist.pspec[1].stepsize;
+    stepsizes[1] = patchlist.pspec[0].stepsize;
+    stepsizes[2] = patchlist.pspec[1].stepsize;
+    stepsizes[3] = patchlist.pspec[0].stepsize;
+  }
+
+  /**
+   * Splits a patch and a bin by an isoparametric line.
+   */
+  private void monosplitInS( Bin source, int start, int end ) {
+    if( source.isnonempty() ) {
+      if( start != end ) {
+        int  i = start + (end - start) / 2;
+        Bin left = new Bin();
+        Bin right = new Bin();
+        split( source, left, right, 0, smbrkpts.pts[i] );
+        monosplitInS( left, start, i );
+        monosplitInS( right, i+1, end );
+      } else {
+        if( renderhints.display_method == NurbsConsts.N_OUTLINE_SUBDIV_S ) {
+          outline( source );
+          freejarcs( source );
+        } else {
+          setArcTypePwl();
+          setDegenerate();
+          findIrregularT( source );
+          monosplitInT( source, tmbrkpts.start, tmbrkpts.end );
+        }
+      }
+    } 
+  }
+
+  /**
+   * Splits a patch and a bin by an isoparametric line.
+   */
+  private void monosplitInT( Bin source, int start, int end ) {
+    if( source.isnonempty() ) {
+      if( start != end ) {
+        int  i = start + (end - start) / 2;
+        Bin left = new Bin();
+        Bin right = new Bin();
+        split( source, left, right, 1, tmbrkpts.pts[i] );
+        monosplitInT( left, start, i );
+        monosplitInT( right, i+1, end );
+      } else {
+        if( renderhints.display_method == NurbsConsts.N_OUTLINE_SUBDIV_ST ) {
+          outline( source );
+          freejarcs( source );
+        } else {
+          /*
+            printf("*******render\n");
+            source.show("source\n");
+          */
+          render( source );
+          freejarcs( source );
+        }
+      }
+    } 
+  }
+
+  /**
+   * Renders the trimmed patch by outlining the boundary .
+   */
+  private void outline( Bin bin ) {
+    bin.markall();
+    for( Arc jarc=bin.firstarc(); jarc != null; jarc=bin.nextarc() ) {
+      if( jarc.ismarked() ) {
+        assert( jarc.check( ) );
+        Arc jarchead = jarc;
+        do {
+          slicer.outline( jarc );
+          jarc.clearmark();
+          jarc = jarc.prev;
+        } while (jarc != jarchead);
+      }
+    }
+  }
+
+  /**
+   * Frees all arcs in a bin.
+   */
+  private void freejarcs( Bin & ) {
+    bin.adopt();  /* XXX - should not be necessary */
+
+    Arc jarc;
+    while( (jarc = bin.removearc()) != null ) {
+      if( jarc.pwlArc != null ) jarc.pwlArc.deleteMe( ); jarc.pwlArc = null;
+      if( jarc.bezierArc != null) jarc.bezierArc.deleteMe( ); jarc.bezierArc = null;
+      jarc.deleteMe( );
+    }
+  }
+
+  /**
+   * Renders all monotone regions in a bin and frees the bin.
+   */
+  private void render( Bin bin ) {
+    bin.markall();
+
+    slicer.setisolines( ( renderhints.display_method == N_ISOLINE_S ) ? 1 : 0 );
+
+    for( Arc jarc=bin.firstarc(); jarc != null; jarc=bin.nextarc() ) {
+      if( jarc.ismarked() ) {
+        assert( jarc.check( ) != 0 );
+        Arc jarchead = jarc;
+        do {
+          jarc.clearmark();
+          jarc = jarc.next;
+        } while (jarc != jarchead);
+        slicer.slice( jarc );
+      }
+    }
+  }
+
+  private void split( Bin &, Bin &, Bin &, int, float );
+
+  /**
+   * Tessellates all Bezier arcs in a bin.
+   * <ol>
+   *   <li> only accepts linear Bezier arcs as input 
+   *   <li> the Bezier arcs are stored in the pwlArc structure
+   *   <li> only vertical or horizontal lines work
+   * </ol>
+   * should:
+   * <ol>
+   *   <li> represent Bezier arcs in BezierArc structure
+   *        (this requires a multitude of changes to the code)
+   *   <li> accept high degree Bezier arcs (hard)
+   *   <il> map the curve onto the surface to determine tessellation
+   *   <li> work for curves of arbitrary geometry
+   * </ol>
+   *----------------------------------------------------------------------------
+   */
+  private void tessellate( Bin bin, float rrate, float trate, float lrate, float brate ) {
+    for( Arc jarc=bin.firstarc(); jarc != null; jarc=bin.nextarc() ) {
+      if( jarc.isbezier( ) ) {
+        assert( jarc.pwlArc.npts == 2 );  
+        TrimVertex[] pts = jarc.pwlArc.pts;
+        float s1 = pts[0].param[0];
+        float t1 = pts[0].param[1];
+        float s2 = pts[1].param[0];
+        float t2 = pts[1].param[1];
+      
+        jarc.pwlArc.deleteMe( );
+        jarc.pwlArc = null;
+      
+        switch( jarc.getside() ) {
+        case Arc.SIDE_LEFT:
+          assert( s1 == s2 );
+          arctessellator.pwl_left( jarc, s1, t1, t2, lrate );
+          break;
+        case Arc.SIDE_RIGHT:
+          assert( s1 == s2 );
+          arctessellator.pwl_right( jarc, s1, t1, t2, rrate );
+          break;
+        case Arc.SIDE_TOP:
+          assert( t1 == t2 );
+          arctessellator.pwl_top( jarc, t1, s1, s2, trate );
+          break;
+        case Arc.SIDE_BOTTOM:
+          assert( t1 == t2 );
+          arctessellator.pwl_bottom( jarc, t1, s1, s2, brate );
+          break;
+        case Arc.SIDE_NONE:
+          throw new InternalError("Incorrect tesselation state");
+          break;
+        }
+        assert( ! jarc.isbezier() );
+        assert( jarc.check() != 0 );
+      }
+    }
+  }
+
+  private inline void setDegenerate( void ) { showDegenerate = 1; }
+  private inline void setNonDegenerate( void ) { showDegenerate = 0; }
+  private inline int showingDegenerate( void ) { return showDegenerate; }
+  private inline void setArcTypeBezier( void ) { isArcTypeBezier = 1; }
+  private inline void setArcTypePwl( void ) { isArcTypeBezier = 0; }
+  private inline int isBezierArcType( void ) { return isArcTypeBezier; }
+
+  /**
+   * If no user input trimming data, then create a trimming curve
+   * around the boundaries of the Quilt. The curve consists of four
+   * Jordan arcs, one for each side of the Quilt, connected, of
+   * course, head to tail.
+   */
+  private void makeBorderTrim( float[] from, float[] to ) {
+    float smin = from[0];
+    float smax = to[0];
+    float tmin = from[1];
+    float tmax = to[1];
+
+    pjarc = null;
+
+    Arc jarc = new Arc( Arc.SIDE_BOTTOM, 0 );
+    arctessellator.bezier( jarc, smin, smax, tmin, tmin );
+    initialbin.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new Arc( Arc.SIDE_RIGHT, 0 );
+    arctessellator.bezier( jarc, smax, smax, tmin, tmax );
+    initialbin.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new Arc( Arc.SIDE_TOP, 0 );
+    arctessellator.bezier( jarc, smax, smin, tmax, tmax );
+    initialbin.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new Arc( Arc.SIDE_LEFT, 0 );
+    arctessellator.bezier( jarc, smin, smin, tmax, tmin );
+    initialbin.addarc( jarc  );
+    jarc.append( pjarc );
+
+    assert( jarc.check() );
+  }
+
+  private void split( Bin &, int, const float *, int, int );
+  private void partition( Bin bin, Bin left, Bin intersections, Bin right, Bin unknown, int param, float value ) {
+    Bin  headonleft = new Bin();
+    Bin headonright = new Bin();
+    Bin tailonleft = new Bin();
+    Bin tailonright = new Bin();
+
+    for( Arc jarc = bin.removearc(); jarc != null; jarc = bin.removearc() ) {
+
+      float tdiff = jarc.tail()[param] - value;
+      float hdiff = jarc.head()[param] - value;
+
+      if( tdiff > 0.0 ) {
+        if( hdiff > 0.0 ) {
+          right.addarc( jarc  );
+        } else if( hdiff == 0.0 ) {
+          tailonright.addarc( jarc  );
+        } else {
+          Arc jtemp;
+          switch( arc_split(jarc, param, value, 0) ) {
+          case 2:
+            tailonright.addarc( jarc  );
+            headonleft.addarc( jarc.next  );
+            break;
+          case 31:
+            assert( jarc.head()[param] > value );
+            right.addarc( jarc  );
+            tailonright.addarc( jtemp = jarc.next  );
+            headonleft.addarc( jtemp.next  );
+            break;
+          case 32:
+            assert( jarc.head()[param] <= value );
+            tailonright .addarc( jarc  );
+            headonleft.addarc( jtemp = jarc.next  );
+            left.addarc( jtemp.next  );
+            break;
+          case 4:
+            right.addarc( jarc  );
+            tailonright.addarc( jtemp = jarc.next  );
+            headonleft.addarc( jtemp = jtemp.next  );
+            left.addarc( jtemp.next  );
+          }
+        }
+      } else if( tdiff == 0.0 ) {
+        if( hdiff > 0.0 ) {
+          headonright.addarc( jarc  );
+        } else if( hdiff == 0.0 ) {
+          unknown.addarc( jarc  );
+        } else {
+          headonleft.addarc( jarc  );
+        }
+      } else {
+        if( hdiff > 0.0 ) {
+          Arc jtemp;
+          switch( arc_split(jarc, param, value, 1) ) {
+          case 2:
+            tailonleft.addarc( jarc  );
+            headonright.addarc( jarc.next  );
+            break;
+          case 31:
+            assert( jarc.head()[param] < value );
+            left.addarc( jarc  );
+            tailonleft.addarc( jtemp = jarc.next  );
+            headonright.addarc( jtemp.next  );
+            break;
+          case 32:
+            assert( jarc.head()[param] >= value );
+            tailonleft.addarc( jarc  );
+            headonright.addarc( jtemp = jarc.next  );
+            right.addarc( jtemp.next  );
+            break;
+          case 4:
+            left.addarc( jarc  );
+            tailonleft.addarc( jtemp = jarc.next  );
+            headonright.addarc( jtemp = jtemp.next  );
+            right.addarc( jtemp.next  );
+          }
+        } else if( hdiff == 0.0 ) {
+          tailonleft.addarc( jarc  );
+        } else {
+          left.addarc( jarc  );
+        }
+      }
+    }
+    if( param == 0 ) {
+      classify_headonleft_s( headonleft, intersections, left, value );
+      classify_tailonleft_s( tailonleft, intersections, left, value );
+      classify_headonright_s( headonright, intersections, right, value );
+      classify_tailonright_s( tailonright, intersections, right, value );
+    } else {
+      classify_headonleft_t( headonleft, intersections, left, value );
+      classify_tailonleft_t( tailonleft, intersections, left, value );
+      classify_headonright_t( headonright, intersections, right, value );
+      classify_tailonright_t( tailonright, intersections, right, value );
+    }
+  }
+
+  /**
+   * Determine points of non-monotonicity in s direction.
+   */
+  private void findIrregularS( Bin bin ) {
+    assert( bin.firstarc() == null || bin.firstarc().check() );
+
+    smbrkpts.grow( bin.numarcs() );
+
+    for( Arc jarc=bin.firstarc(); jarc != null; jarc=bin.nextarc() ) {
+      float[] a = jarc.prev.tail();
+      float[] b = jarc.tail();
+      float[] c = jarc.head();
+
+      if( b[1] == a[1] && b[1] == c[1] ) continue;
+
+      //corrected code
+      if((b[1]<=a[1] && b[1] <= c[1]) ||
+         (b[1]>=a[1] && b[1] >= c[1]))
+        {
+          //each arc (jarc, jarc.prev, jarc.next) is a 
+          //monotone arc consisting of multiple line segements.
+          //it may happen that jarc.prev and jarc.next are the same,
+          //that is, jarc.prev and jarc form a closed loop.
+          //In such case, a and c will be the same.
+          if(a[0]==c[0] && a[1] == c[1])
+            {
+              if(jarc.pwlArc.npts >2)
+                {
+                  c = jarc.pwlArc.pts[jarc.pwlArc.npts-2].param;
+                }
+              else
+                {
+                  assert(jarc.prev.pwlArc.npts>2);
+                  a = jarc.prev.pwlArc.pts[jarc.prev.pwlArc.npts-2].param;
+                }
+        
+            }
+          if(area(a,b,c) < 0)
+            {
+              smbrkpts.add(b[0]);
+            }
+
+        }
+
+      /* old code, 
+         if( b[1] <= a[1] && b[1] <= c[1] ) {
+         if( ! ccwTurn_tr( jarc.prev, jarc ) )
+         smbrkpts.add( b[0] );
+         } else if( b[1] >= a[1] && b[1] >= c[1] ) {
+         if( ! ccwTurn_tl( jarc.prev, jarc ) )
+         smbrkpts.add( b[0] );
+         }
+      */
+
+    }
+
+    smbrkpts.filter();
+  }
+
+  /**
+   * Determines points of non-monotonicity in t direction where one
+   * arc is parallel to the s axis.
+   */
+  private void findIrregularT( Bin bin ) {
+    assert( bin.firstarc() == null || bin.firstarc().check() );
+
+    tmbrkpts.grow( bin.numarcs() );
+
+    for( Arc jarc=bin.firstarc(); jarc != null; jarc=bin.nextarc() ) {
+      float[] a = jarc.prev.tail();
+      float[] b = jarc.tail();
+      float[] c = jarc.head();
+
+      if( b[0] == a[0] && b[0] == c[0] ) continue;
+
+      if( b[0] <= a[0] && b[0] <= c[0] ) {
+        if( a[1] != b[1] && b[1] != c[1] ) continue; 
+        if( ccwTurn_sr( jarc.prev, jarc ) == 0)
+          tmbrkpts.add( b[1] );
+      } else if ( b[0] >= a[0] && b[0] >= c[0] ) {
+        if( a[1] != b[1] && b[1] != c[1] ) continue; 
+        if( ccwTurn_sl( jarc.prev, jarc ) == 0)
+          tmbrkpts.add( b[1] );
+      }
+    }
+    tmbrkpts.filter( );
+  }
+
+
+  private int bbox( TrimVertex a, TrimVertex b, TrimVertex c, int p ) {
+    return bbox( a.param[p], b.param[p], c.param[p],
+           a.param[1-p], b.param[1-p], c.param[1-p] );
+  }
+
+  private static int bbox( float sa, float sb, float sc, float ta, float tb, float tc ) {
+    assert( tc >= ta );
+    assert( tc <= tb );
+
+    if( sa < sb ) {
+      if( sc <= sa ) {
+        return -1;
+      } else if( sb <= sc ) {
+        return 1;
+      } else {
+        return 0;
+      }
+    } else if( sa > sb ) {
+      if( sc >= sa ) {
+        return 1;
+      } else if( sb >= sc ) {
+        return -1;
+      } else {
+        return 0;
+      }
+    } else {
+      if( sc > sa ) {
+        return 1;
+      } else if( sb > sc ) {
+        return -1;
+      } else {
+        return 0;
+      }
+    }
+  }
+  /**
+   * Determines how three points are oriented by computing their
+   * determinant.
+   *
+   * @return 1 if the vertices are ccw oriented, 0 if they are cw
+   * oriented, or -1 if the computation is ill-conditioned.
+   */
+  private static int ccw( TrimVertex a, TrimVertex b, TrimVertex c ) {
+    float d = TrimVertex.det3( a, b, c );
+    if( Math.abs(d) < 0.0001 ) return -1;
+    return (d < 0.0) ? 0 : 1;
+  }
+  private void join_s( Bin &, Bin &, Arc_ptr, Arc_ptr  );
+  private void join_t( Bin &, Bin &, Arc_ptr , Arc_ptr  );
+
+  private static void vert_interp( TrimVertex n, TrimVertex l, TrimVertex r, int p, float val ) {
+    assert( val > l.param[p]);
+    assert( val < r.param[p]);
+
+    n.nuid = l.nuid;
+
+    n.param[p] = val;
+    if( l.param[1-p] != r.param[1-p]  ) {
+      float ratio = (val - l.param[p]) / (r.param[p] - l.param[p]);
+      n.param[1-p] = l.param[1-p] + 
+        ratio * (r.param[1-p] - l.param[1-p]);
+    } else {
+      n.param[1-p] = l.param[1-p];
+    }
+  }
+
+  private static final int INTERSECT_VERTEX = 1;
+  private static final int INTERSECT_EDGE   = 2;
+
+  /**
+   * Finds intersection of pwlArc and isoparametric line.
+   */
+  private static int pwlarc_intersect( PwlArc pwlArc, int param, float value, int dir, int[] loc ) {
+    assert( pwlArc.npts > 0 );
+
+    if( dir != 0 ) {
+      TrimVertex[] v = pwlArc.pts;
+      int imin = 0; 
+      int imax = pwlArc.npts - 1;
+      assert( value > v[imin].param[param] );
+      assert( value < v[imax].param[param] );	
+      while( (imax - imin) > 1 ) {
+        int imid = (imax + imin)/2;
+        if( v[imid].param[param] > value )
+          imax = imid;
+        else if( v[imid].param[param] < value )
+          imin = imid;
+        else {
+          loc[1] = imid;
+          return INTERSECT_VERTEX;
+        }
+      }
+      loc[0] = imin;
+      loc[2] = imax;
+      return INTERSECT_EDGE;
+    } else {
+      TrimVertex[] v = pwlArc.pts;
+      int imax = 0; 
+      int imin = pwlArc.npts - 1;
+      assert( value > v[imin].param[param] );
+      assert( value < v[imax].param[param] );	
+      while( (imin - imax) > 1 ) {
+        int imid = (imax + imin)/2;
+        if( v[imid].param[param] > value )
+          imax = imid;
+        else if( v[imid].param[param] < value )
+          imin = imid;
+        else {
+          loc[1] = imid;
+          return INTERSECT_VERTEX;
+        }
+      }
+      loc[0] = imin;
+      loc[2] = imax;
+      return INTERSECT_EDGE;
+    }
+  }
+
+  private int arc_split( Arc jarc , int param, float value, int dir ) {
+    int maxvertex = jarc.pwlArc.npts;
+    Arc jarc1, jarc2, jarc3;
+    TrimVertex v = jarc.pwlArc.pts;
+
+    int[] loc = new int[3];
+    switch( pwlarc_intersect( jarc.pwlArc, param, value, dir, loc ) ) {
+
+      // When the parameter value lands on a vertex, life is sweet
+    case INTERSECT_VERTEX: {
+      jarc1 = new Arc( jarc, new PwlArc( maxvertex-loc[1], /* &v[loc[1]] */ v, loc[1] ) );
+      jarc.pwlArc.npts = loc[1] + 1;
+      jarc1.next = jarc.next;
+      jarc1.next.prev = jarc1;
+      jarc.next = jarc1;
+      jarc1.prev = jarc;
+      assert(jarc.check());
+      return 2;
+    }
+
+      // When the parameter value intersects an edge, we have to
+      // interpolate a new vertex.  There are special cases
+      // if the new vertex is adjacent to one or both of the
+      // endpoints of the arc.
+    case INTERSECT_EDGE: {
+      int i, j;
+      if( dir == 0 ) {
+        i = loc[0];
+        j = loc[2];
+      } else {
+        i = loc[2];
+        j = loc[0];
+      }
+
+      // The split is between vertices at index j and i, in that
+      // order (j < i)
+      
+      // JEB:  This code is my idea of how to do the split without
+      // increasing the number of links.  I'm doing this so that
+      // the is_rect routine can recognize rectangles created by
+      // subdivision.  In exchange for simplifying the curve list,
+      // however, it costs in allocated space and vertex copies.
+      
+      TrimVertex[] newjunk = TrimVertex.allocate(maxvertex -i+1 /*-j*/);
+      int k;
+      for(k=0; k<maxvertex-i; k++)
+        {
+          newjunk[k+1] = v[i+k];
+          newjunk[k+1].nuid = jarc.nuid;
+        }
+      
+      TrimVertex[] vcopy = TrimVertex.allocate(maxvertex);
+      for(k=0; k<maxvertex; k++)
+        {
+          vcopy[k].param[0] = v[k].param[0];
+          vcopy[k].param[1] = v[k].param[1];
+        }
+      jarc.pwlArc.pts=vcopy;
+
+      v[i].nuid = jarc.nuid;
+      v[j].nuid = jarc.nuid;
+      vert_interp( newjunk[0], v[loc[0]], v[loc[2]], param, value );
+
+      if( showingDegenerate() )
+        backend.triangle( v[i], newjunk[0], v[j] );
+
+      vcopy[j+1].param[0]=newjunk[0].param[0];
+      vcopy[j+1].param[1]=newjunk[0].param[1];
+
+
+      jarc1 = new Arc( jarc,
+                       new PwlArc(maxvertex-i+1 , newjunk ) );
+
+      jarc.pwlArc.npts = j+2;
+      jarc1.next = jarc.next;
+      jarc1.next.prev = jarc1;
+      jarc.next = jarc1;
+      jarc1.prev = jarc;
+      assert(jarc.check());
+
+      return 2;
+
+      /***
+      // JEB: This is the original version:
+
+      TrimVertex[] newjunk = TrimVertex.allocate(3);
+      v[i].nuid = jarc.nuid;
+      v[j].nuid = jarc.nuid;
+      newjunk[0] = v[j];
+      newjunk[2] = v[i];
+      vert_interp( &newjunk[1], &v[loc[0]], &v[loc[2]], param, value );
+
+      if( showingDegenerate() )
+        backend.triangle( &newjunk[2], &newjunk[1], &newjunk[0] );
+
+      // New vertex adjacent to both endpoints
+      if (maxvertex == 2) {
+        jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+        jarc.pwlArc.npts = 2;
+        jarc.pwlArc.pts = newjunk;
+        jarc1.next = jarc.next;
+        jarc1.next.prev = jarc1;
+        jarc.next = jarc1;
+        jarc1.prev = jarc;
+        assert(jarc.check() != 0);
+
+        return 2;
+
+        // New vertex adjacent to ending point of arc
+      } else if (maxvertex - j == 2) {
+        jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
+        jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+        jarc.pwlArc.npts = maxvertex-1;
+        jarc2.next = jarc.next;
+        jarc2.next.prev = jarc2;
+        jarc.next = jarc1;
+        jarc1.prev = jarc;
+        jarc1.next = jarc2;
+        jarc2.prev = jarc1;
+        assert(jarc.check() != 0);
+        return 31;
+
+        // New vertex adjacent to starting point of arc
+      } else if (i == 1) {
+        jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+        jarc2 = new(arcpool) Arc( jarc, 
+                                  new(pwlarcpool) PwlArc( maxvertex-1, &jarc.pwlArc.pts[1] ) );
+        jarc.pwlArc.npts = 2;
+        jarc.pwlArc.pts = newjunk;
+        jarc2.next = jarc.next;
+        jarc2.next.prev = jarc2;
+        jarc.next = jarc1;
+        jarc1.prev = jarc;
+        jarc1.next = jarc2;
+        jarc2.prev = jarc1;
+        assert(jarc.check() != 0);
+        return 32;
+
+        // It's somewhere in the middle
+      } else {
+        jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
+        jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
+        jarc3 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( maxvertex-i, v+i ) );
+        jarc.pwlArc.npts = j + 1;
+        jarc3.next = jarc.next;
+        jarc3.next.prev = jarc3;
+        jarc.next = jarc1;
+        jarc1.prev = jarc;
+        jarc1.next = jarc2;
+        jarc2.prev = jarc1;
+        jarc2.next = jarc3;
+        jarc3.prev = jarc2;
+        assert(jarc.check() != 0);
+        return 4;
+      }
+      ***/
+    }
+    default:
+      return -1; //picked -1 since it's not used
+    }
+  }
+
+  private void check_s( Arc_ptr , Arc_ptr  );
+  private void check_t( Arc_ptr , Arc_ptr  );
+  private inline void link( Arc_ptr , Arc_ptr , Arc_ptr , Arc_ptr  );
+  private inline void simple_link( Arc_ptr , Arc_ptr  );
+
+  private Bin makePatchBoundary( const float[] from, const float[] to ) {
+    Bin ret = new Bin();
+    float smin = from[0];
+    float smax = to[0];
+    float tmin = from[1];
+    float tmax = to[1];
+
+    pjarc = 0;
+
+    Arc jarc = new Arc( arc_bottom, 0 );
+    arctessellator.bezier( jarc, smin, smax, tmin, tmin );
+    ret.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new(arcpool) Arc( arc_right, 0 );
+    arctessellator.bezier( jarc, smax, smax, tmin, tmax );
+    ret.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new(arcpool) Arc( arc_top, 0 );
+    arctessellator.bezier( jarc, smax, smin, tmax, tmax );
+    ret.addarc( jarc  );
+    pjarc = jarc.append( pjarc );
+
+    jarc = new(arcpool) Arc( arc_left, 0 );
+    arctessellator.bezier( jarc, smin, smin, tmax, tmin );
+    ret.addarc( jarc  );
+    jarc.append( pjarc );
+
+    assert( jarc.check() != 0 );
+    return ret;
+  }
+
+   /*in domain distance method, the tessellation is controled by two numbers:
+    *GLU_U_STEP: number of u-segments per unit u length of domain
+    *GLU_V_STEP: number of v-segments per unit v length of domain
+    *These two numbers are normally stored in mapdesc.maxs(t)rate.
+    *I (ZL) put these two numbers here so that I can optimize the untrimmed 
+    *case in the case of domain distance sampling.
+    *These two numbers are set by set_domain_distance_u_rate() and ..._v_..().
+    */
+  private float domain_distance_u_rate;
+  private float domain_distance_v_rate;
+  private int is_domain_distance_sampling;
+  
+}