ImmModeSink: Fix bugs (use glBufferUsage, vboUsage, GL_POLYGON, GL_QUADS) and add API docs. (API Change)

- Changed create*(..) factory methods (API Change)
  - Drop passing GL instance, not needed
    - allows creation of ImmModeSink as final field w/o GL context
  - Use 'glBufferUsage' to determine whether to use VBO or not ( 0 == glBufferUsage )

- Use glBufferUsage in glBufferData(..) call (oops)

- Toggle vboUsage per object ( 0 == glBufferUsage ? nonVBO : VBO )
  remove static VBO usage flag

- Fix render mode
  - GL_POLYGON -> GL_TRIANGLE_FAN (not GL_LINES)
  - GL_QUADS -> Looped GL_TRIANGLE_FAN (is !GL2) in draw(..) w/ and w/o indices

- Buffer usage

  - documented

  - allow creating sink w/ all components (vertices, color, normal and texCoords)
    bit render and grow only used parts.
    This allows proper usage of sink where it is not known
    which types are being used.

- Added test case

- Manually tested w/ Jake2 ES1
  Jake2 uses the FFP immediate mode rendering, where we utilize this sink
  w/o rendering artifacts.

1 files changed, 408 insertions, 233 deletions

diff --git a/src/jogl/classes/com/jogamp/opengl/util/ImmModeSink.java b/src/jogl/classes/com/jogamp/opengl/util/ImmModeSink.java
index cf0373044..238e402d1 100644
--- a/src/jogl/classes/com/jogamp/opengl/util/ImmModeSink.java
+++ b/src/jogl/classes/com/jogamp/opengl/util/ImmModeSink.java
@@ -13,52 +13,107 @@ import javax.media.opengl.GL2ES2;
 import javax.media.opengl.GLException;
 import javax.media.opengl.fixedfunc.GLPointerFunc;
 
-import com.jogamp.common.util.ReflectionUtil;
 import com.jogamp.opengl.util.glsl.ShaderState;
 
+/**
+ * <p>
+ * Immediate mode sink, implementing OpenGL fixed function subset of immediate mode operations, i.e.
+ * <pre>
+ *   glBegin();
+ *     glVertex3f(1f, 1f, 1f);
+ *     glColor4f(1f, 1f, 1f, 1f);
+ *     ...
+ *   glEnd();
+ * </pre>
+ * Implementation buffers all vertex, colors, normal and texture-coord elements in their respective buffers
+ * to be either rendered directly via {@link #glEnd(GL)} or to be added to an internal display list
+ * via {@link #glEnd(GL, boolean) glEnd(gl, false)} for deferred rendering via {@link #draw(GL, boolean)}.
+ * </p>
+ * <a name="storageDetails"><h5>Buffer storage and it's creation via {@link #createFixed(int, int, int, int, int, int, int, int, int, int) createFixed(..)} 
+ * and {@link #createGLSL(int, int, int, int, int, int, int, int, int, int) createGLSL(..)}</h5></a> 
+ * <p>
+ * If unsure whether <i>colors</i>, <i>normals</i> and <i>textures</i> will be used, 
+ * simply add them with an expected component count.
+ * This implementation will only render buffers which are being filled.<br/>
+ * The buffer growing implementation will only grow the exceeded buffers, unused buffers are not resized.
+ * </p>
+ * <p>
+ * Note: Optional types, i.e. color, must be either not used or used w/ the same element count as vertex, etc. 
+ * This is a semantic constraint, same as in the original OpenGL spec.
+ * </p>
+ */
 public class ImmModeSink {
 
   public static final boolean DEBUG_BEGIN_END = false;
   public static final boolean DEBUG_DRAW = false;
+  public static final boolean DEBUG_BUFFER = false;
 
-  // public static final int GL_QUADS      = 0x0007; // Needs data manipulation
+  public static final int GL_QUADS      = 0x0007; // Needs data manipulation on ES1/ES2
   public static final int GL_QUAD_STRIP = 0x0008;
   public static final int GL_POLYGON    = 0x0009;
 
   /**
    * Uses a GL2ES1, or ES2 fixed function emulation immediate mode sink
+   * <p>
+   * See <a href="#storageDetails"> buffer storage details</a>.
+   * </p>
+   * 
+   * @param initialElementCount initial buffer size, if subsequent mutable operations are about to exceed the buffer size, the buffer will grow about the initial size.
+   * @param vComps mandatory vertex component count, should be 2, 3 or 4.
+   * @param vDataType mandatory vertex data type, e.g. {@link GL#GL_FLOAT}
+   * @param cComps optional color component count, may be 0, 3 or 4
+   * @param cDataType optional color data type, e.g. {@link GL#GL_FLOAT}
+   * @param nComps optional normal component count, may be 0, 3 or 4
+   * @param nDataType optional normal data type, e.g. {@link GL#GL_FLOAT}
+   * @param tComps optional texture-coordinate  component count, may be 0, 2 or 3
+   * @param tDataType optional texture-coordinate data type, e.g. {@link GL#GL_FLOAT}
+   * @param glBufferUsage VBO <code>usage</code> parameter for {@link GL#glBufferData(int, long, Buffer, int)}, e.g. {@link GL#GL_STATIC_DRAW}, 
+   *                      set to <code>0</code> for no VBO usage
    */
-  public static ImmModeSink createFixed(GL gl, int glBufferUsage, int initialElementCount,
+  public static ImmModeSink createFixed(int initialElementCount, 
                                         int vComps, int vDataType,
-                                        int cComps, int cDataType, 
+                                        int cComps, int cDataType,
                                         int nComps, int nDataType, 
-                                        int tComps, int tDataType) {
-    return new ImmModeSink(gl, glBufferUsage, initialElementCount, 
-                           vComps, vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, false);
+                                        int tComps, int tDataType, 
+                                        int glBufferUsage) {
+    return new ImmModeSink(initialElementCount, vComps, 
+                           vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, false, glBufferUsage);
   }
 
   /**
    * Uses a GL2ES2 GLSL shader immediate mode sink.
    * To issue the draw() command,
    * a ShaderState must be current, using ShaderState.glUseProgram().
-   *
+   * <p>
+   * See <a href="#storageDetails"> buffer storage details</a>.
+   * </p>
+   * 
+   * @param initialElementCount initial buffer size, if subsequent mutable operations are about to exceed the buffer size, the buffer will grow about the initial size.
+   * @param vComps mandatory vertex component count, should be 2, 3 or 4.
+   * @param vDataType mandatory vertex data type, e.g. {@link GL#GL_FLOAT}
+   * @param cComps optional color component count, may be 0, 3 or 4
+   * @param cDataType optional color data type, e.g. {@link GL#GL_FLOAT}
+   * @param nComps optional normal component count, may be 0, 3 or 4
+   * @param nDataType optional normal data type, e.g. {@link GL#GL_FLOAT}
+   * @param tComps optional texture-coordinate  component count, may be 0, 2 or 3
+   * @param tDataType optional texture-coordinate data type, e.g. {@link GL#GL_FLOAT}
+   * @param glBufferUsage VBO <code>usage</code> parameter for {@link GL#glBufferData(int, long, Buffer, int)}, e.g. {@link GL#GL_STATIC_DRAW}, 
+   *                      set to <code>0</code> for no VBO usage
+   * 
    * @see #draw(GL, boolean)
    * @see com.jogamp.opengl.util.glsl.ShaderState#useProgram(GL2ES2, boolean)
    * @see com.jogamp.opengl.util.glsl.ShaderState#getCurrentShaderState()
    */
-  public static ImmModeSink createGLSL(GL gl, int glBufferUsage, int initialElementCount,
+  public static ImmModeSink createGLSL(int initialElementCount, 
                                        int vComps, int vDataType,
-                                       int cComps, int cDataType, 
+                                       int cComps, int cDataType,
                                        int nComps, int nDataType, 
-                                       int tComps, int tDataType) {
-    return new ImmModeSink(gl, glBufferUsage, initialElementCount, 
-                           vComps, vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, true);
+                                       int tComps, int tDataType, 
+                                       int glBufferUsage) {
+    return new ImmModeSink(initialElementCount, vComps, 
+                           vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, true, glBufferUsage);
   }
 
-  public static boolean usesVBO() { return vboUsage; }
-
-  public static void setVBOUsage(boolean v) { vboUsage = v; }
-
   public void destroy(GL gl) {
     destroyList(gl);
 
@@ -93,42 +148,35 @@ public class ImmModeSink {
 
   public void draw(GL gl, boolean disableBufferAfterDraw) {
     if(DEBUG_DRAW) {
-        Exception e = new Exception("Info: ImmModeSink.draw(disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
-        e.printStackTrace();
+        System.err.println("ImmModeSink.draw(disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
     }
     int n=0;
-    for(Iterator<VBOSet> i=vboSetList.iterator(); i.hasNext() ; n++) {
-        i.next().draw(gl, null, disableBufferAfterDraw, n);
+    for(int i=0; i<vboSetList.size(); i++, n++) {
+        vboSetList.get(i).draw(gl, null, disableBufferAfterDraw, n);
     }
   }
 
   public void draw(GL gl, Buffer indices, boolean disableBufferAfterDraw) {
     if(DEBUG_DRAW) {
-        Exception e = new Exception("Info: ImmModeSink.draw(disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
-        e.printStackTrace();
+        System.err.println("ImmModeSink.draw(disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
     }
     int n=0;
-    for(Iterator<VBOSet> i=vboSetList.iterator(); i.hasNext() ; n++) {
-        i.next().draw(gl, indices, disableBufferAfterDraw, n);
+    for(int i=0; i<vboSetList.size(); i++, n++) {
+        vboSetList.get(i).draw(gl, indices, disableBufferAfterDraw, n);
     }
   }
 
   public void glBegin(int mode) {
     if(DEBUG_BEGIN_END) {
-        Exception e = new Exception("Info: ImmModeSink.glBegin("+vboSet.mode+"):\n\t"+this);
-        e.printStackTrace();
+        System.err.println("ImmModeSink.glBegin("+vboSet.mode+"):\n\t"+this);
     }
     vboSet.modeOrig = mode;
     switch(mode) {
-        // Needs data manipulation ..
-        //case GL_QUADS:
-        //    mode=GL.GL_LINES;
-        //    break;
         case GL_QUAD_STRIP:
             mode=GL.GL_TRIANGLE_STRIP;
             break;
         case GL_POLYGON:
-            mode=GL.GL_LINES;
+            mode=GL.GL_TRIANGLE_FAN;
             break;
     }
     vboSet.mode = mode;
@@ -149,8 +197,7 @@ public class ImmModeSink {
 
   private void glEnd(GL gl, Buffer indices, boolean immediateDraw) {
     if(DEBUG_BEGIN_END) {
-        Exception e = new Exception("Info: ImmModeSink START glEnd(immediate: "+immediateDraw+"):\n\t"+this);
-        e.printStackTrace();
+        System.err.println("ImmModeSink START glEnd(immediate: "+immediateDraw+"):\n\t"+this);
     }
     if(immediateDraw) {
         vboSet.seal(gl, true);
@@ -160,7 +207,10 @@ public class ImmModeSink {
         vboSet.seal(gl, true);
         vboSet.enableBuffer(gl, false);
         vboSetList.add(vboSet);
-        vboSet = vboSet.regenerate();
+        vboSet = vboSet.regenerate(gl);
+    }
+    if(DEBUG_BEGIN_END) {
+        System.err.println("ImmModeSink END glEnd(immediate: "+immediateDraw+"):\n\t"+this);
     }
   }
 
@@ -261,37 +311,34 @@ public class ImmModeSink {
     vboSet.glTexCoord3b(x,y,z);
   }
 
-  protected ImmModeSink(GL gl, int glBufferUsage, int initialElementCount,
-                        int vComps, int vDataType,
-                        int cComps, int cDataType, 
-                        int nComps, int nDataType, 
-                        int tComps, int tDataType, boolean useGLSL) {
-    if(useGLSL && !gl.hasGLSL()) {
-        throw new GLException("ImmModeSink GLSL usage not supported: "+gl);
-    }
-    vboSet = new  VBOSet(gl, glBufferUsage, initialElementCount, 
-                         vComps, vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, useGLSL);
+  protected ImmModeSink(int initialElementCount, int vComps,
+                        int vDataType, int cComps,
+                        int cDataType, int nComps, 
+                        int nDataType, int tComps, 
+                        int tDataType, boolean useGLSL, int glBufferUsage) {
+    vboSet = new  VBOSet(initialElementCount, vComps, 
+                         vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, useGLSL, glBufferUsage);
     this.vboSetList   = new ArrayList<VBOSet>();
   }
-
+  
+  public boolean getUseVBO() { return vboSet.getUseVBO(); }
+  
   private void destroyList(GL gl) {
-    for(Iterator<VBOSet> i=vboSetList.iterator(); i.hasNext() ; ) {
-        i.next().destroy(gl);
+    for(int i=0; i<vboSetList.size(); i++) {
+        vboSetList.get(i).destroy(gl);
     }
     vboSetList.clear();
   }
 
   private VBOSet vboSet;
-  private ArrayList<VBOSet> vboSetList;
-  private static boolean vboUsage = true;
+  private final ArrayList<VBOSet> vboSetList;
 
   protected static class VBOSet {
-    protected VBOSet (GL gl, int glBufferUsage, int initialElementCount,
-                      int vComps, int vDataType,
-                      int cComps, int cDataType, 
-                      int nComps, int nDataType, 
-                      int tComps, int tDataType, boolean useGLSL) {
-        this.gl=gl;
+    protected VBOSet (int initialElementCount, int vComps,
+                      int vDataType, int cComps,
+                      int cDataType, int nComps, 
+                      int nDataType, int tComps, 
+                      int tDataType, boolean useGLSL, int glBufferUsage) {
         this.glBufferUsage=glBufferUsage;
         this.initialElementCount=initialElementCount;
         this.vDataType=vDataType;
@@ -303,8 +350,19 @@ public class ImmModeSink {
         this.tDataType=tDataType;
         this.tComps=tComps;
         this.useGLSL=useGLSL;
-
-        allocateBuffer(initialElementCount);
+        this.useVBO = 0 != glBufferUsage;
+        this.vboName = 0;
+        
+        this.vCount=0;
+        this.cCount=0;
+        this.nCount=0;
+        this.tCount=0;
+        this.vElems=0;
+        this.cElems=0;
+        this.nElems=0;
+        this.tElems=0;
+        
+        reallocateBuffer(initialElementCount);
         rewind();
 
         this.sealed=false;
@@ -315,9 +373,11 @@ public class ImmModeSink {
         this.bufferWritten=false;
     }
 
-    protected final VBOSet regenerate() {
-        return new VBOSet(gl, glBufferUsage, initialElementCount, 
-                          vComps, vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, useGLSL);
+    protected boolean getUseVBO() { return useVBO; }
+    
+    protected final VBOSet regenerate(GL gl) {
+        return new VBOSet(initialElementCount, vComps, 
+                          vDataType, cComps, cDataType, nComps, nDataType, tComps, tDataType, useGLSL, glBufferUsage);
     }
 
     protected void checkSeal(boolean test) throws GLException {
@@ -336,33 +396,55 @@ public class ImmModeSink {
     protected void draw(GL gl, Buffer indices, boolean disableBufferAfterDraw, int i)
     {
         if(DEBUG_DRAW) {
-            Exception e = new Exception("Info: ImmModeSink.draw["+i+"](disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
-            e.printStackTrace();
+            System.err.println("ImmModeSink.draw["+i+"].0 (disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
         }
         enableBuffer(gl, true);
 
         if (buffer!=null) {
             if(null==indices) {
-                gl.glDrawArrays(mode, 0, count);
+                if ( GL_QUADS == mode && !gl.isGL2() ) {
+                    for (int j = 0; j < vElems - 3; j += 4) {
+                        gl.glDrawArrays(GL.GL_TRIANGLE_FAN, j, 4);
+                    }
+                } else {
+                    gl.glDrawArrays(mode, 0, vElems);
+                }
             } else {
-                Class<?> clazz = indices.getClass();
                 int type=-1;
-                if(ReflectionUtil.instanceOf(clazz, ByteBuffer.class.getName())) {
+                if(indices instanceof ByteBuffer) {
                     type =  GL.GL_UNSIGNED_BYTE;
-                } else if(ReflectionUtil.instanceOf(clazz, ShortBuffer.class.getName())) {
+                } else if(indices instanceof ShortBuffer) {
                     type =  GL.GL_UNSIGNED_SHORT;
+                } else {
+                    throw new GLException("Given Buffer Class not supported: "+indices.getClass()+", should be ubyte or ushort:\n\t"+this);
                 }
-                if(0>type) {
-                    throw new GLException("Given Buffer Class not supported: "+clazz+", should be ubyte or ushort:\n\t"+this);
+                
+                if ( GL_QUADS == mode && !gl.isGL2() ) {
+                    if( GL.GL_UNSIGNED_BYTE == type ) {
+                        final ByteBuffer b = (ByteBuffer) indices;
+                        for (int j = 0; j < b.remaining(); j++) {
+                            gl.glDrawArrays(GL.GL_TRIANGLE_FAN, (int)(0x000000ff & b.get(j)), 4);
+                        }                        
+                    } else {
+                        final ShortBuffer b = (ShortBuffer) indices;
+                        for (int j = 0; j < b.remaining(); j++) {
+                            gl.glDrawArrays(GL.GL_TRIANGLE_FAN, (int)(0x0000ffff & b.get(j)), 4);
+                        }                                                
+                    }
+                } else {
+                    gl.glDrawElements(mode, indices.remaining(), type, indices);
+                    // GL2: gl.glDrawRangeElements(mode, 0, indices.remaining()-1, indices.remaining(), type, indices);
                 }
-                gl.glDrawElements(mode, indices.remaining(), type, indices);
-                // GL2: gl.glDrawRangeElements(mode, 0, indices.remaining()-1, indices.remaining(), type, indices);
             }
         }
 
         if(disableBufferAfterDraw) {
             enableBuffer(gl, false);
         }
+        
+        if(DEBUG_DRAW) {
+            System.err.println("ImmModeSink.draw["+i+"].X (disableBufferAfterDraw: "+disableBufferAfterDraw+"):\n\t"+this);
+        }
     }
 
     public void glVertexv(Buffer v) {
@@ -384,7 +466,7 @@ public class ImmModeSink {
 
     public void glVertex2b(byte x, byte y) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 2);
+        growBuffer(VERTEX, 2);
         if(vComps>0) 
             GLBuffers.putb(vertexArray, x);
         if(vComps>1) 
@@ -393,7 +475,7 @@ public class ImmModeSink {
     }
     public void glVertex3b(byte x, byte y, byte z) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 3);
+        growBuffer(VERTEX, 3);
         if(vComps>0) 
             GLBuffers.putb(vertexArray, x);
         if(vComps>1) 
@@ -404,7 +486,7 @@ public class ImmModeSink {
     }
     public void glVertex2s(short x, short y) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 2);
+        growBuffer(VERTEX, 2);
         if(vComps>0) 
             GLBuffers.puts(vertexArray, x);
         if(vComps>1) 
@@ -413,7 +495,7 @@ public class ImmModeSink {
     }
     public void glVertex3s(short x, short y, short z) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 3);
+        growBuffer(VERTEX, 3);
         if(vComps>0) 
             GLBuffers.puts(vertexArray, x);
         if(vComps>1) 
@@ -424,7 +506,7 @@ public class ImmModeSink {
     }
     public void glVertex2f(float x, float y) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 2);
+        growBuffer(VERTEX, 2);
         if(vComps>0) 
             GLBuffers.putf(vertexArray, x);
         if(vComps>1) 
@@ -433,7 +515,7 @@ public class ImmModeSink {
     }
     public void glVertex3f(float x, float y, float z) {
         checkSeal(false);
-        growBufferIfNecessary(VERTEX, 3);
+        growBuffer(VERTEX, 3);
         if(vComps>0) 
             GLBuffers.putf(vertexArray, x);
         if(vComps>1) 
@@ -445,7 +527,7 @@ public class ImmModeSink {
 
     public void glNormal3b(byte x, byte y, byte z) {
         checkSeal(false);
-        growBufferIfNecessary(NORMAL, 3);
+        growBuffer(NORMAL, 3);
         if(nComps>0) 
             GLBuffers.putb(normalArray, x);
         if(nComps>1) 
@@ -456,7 +538,7 @@ public class ImmModeSink {
     }
     public void glNormal3s(short x, short y, short z) {
         checkSeal(false);
-        growBufferIfNecessary(NORMAL, 3);
+        growBuffer(NORMAL, 3);
         if(nComps>0) 
             GLBuffers.puts(normalArray, x);
         if(nComps>1) 
@@ -467,7 +549,7 @@ public class ImmModeSink {
     }
     public void glNormal3f(float x, float y, float z) {
         checkSeal(false);
-        growBufferIfNecessary(NORMAL, 3);
+        growBuffer(NORMAL, 3);
         if(nComps>0) 
             GLBuffers.putf(normalArray, x);
         if(nComps>1) 
@@ -479,7 +561,7 @@ public class ImmModeSink {
 
     public void glColor3b(byte r, byte g, byte b) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 3);
+        growBuffer(COLOR, 3);
         if(cComps>0) 
             GLBuffers.putb(colorArray, r);
         if(cComps>1) 
@@ -490,7 +572,7 @@ public class ImmModeSink {
     }
     public void glColor4b(byte r, byte g, byte b, byte a) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 4);
+        growBuffer(COLOR, 4);
         if(cComps>0) 
             GLBuffers.putb(colorArray, r);
         if(cComps>1) 
@@ -503,7 +585,7 @@ public class ImmModeSink {
     }
     public void glColor3s(short r, short g, short b) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 3);
+        growBuffer(COLOR, 3);
         if(cComps>0) 
             GLBuffers.puts(colorArray, r);
         if(cComps>1) 
@@ -514,7 +596,7 @@ public class ImmModeSink {
     }
     public void glColor4s(short r, short g, short b, short a) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 4);
+        growBuffer(COLOR, 4);
         if(cComps>0) 
             GLBuffers.puts(colorArray, r);
         if(cComps>1) 
@@ -527,7 +609,7 @@ public class ImmModeSink {
     }
     public void glColor3f(float r, float g, float b) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 3);
+        growBuffer(COLOR, 3);
         if(cComps>0) 
             GLBuffers.putf(colorArray, r);
         if(cComps>1) 
@@ -538,7 +620,7 @@ public class ImmModeSink {
     }
     public void glColor4f(float r, float g, float b, float a) {
         checkSeal(false);
-        growBufferIfNecessary(COLOR, 4);
+        growBuffer(COLOR, 4);
         if(cComps>0) 
             GLBuffers.putf(colorArray, r);
         if(cComps>1) 
@@ -552,7 +634,7 @@ public class ImmModeSink {
 
     public void glTexCoord2b(byte x, byte y) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 2);
+        growBuffer(TEXTCOORD, 2);
         if(tComps>0) 
             GLBuffers.putb(textCoordArray, x);
         if(tComps>1) 
@@ -561,7 +643,7 @@ public class ImmModeSink {
     }
     public void glTexCoord3b(byte x, byte y, byte z) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 3);
+        growBuffer(TEXTCOORD, 3);
         if(tComps>0) 
             GLBuffers.putb(textCoordArray, x);
         if(tComps>1) 
@@ -572,7 +654,7 @@ public class ImmModeSink {
     }
     public void glTexCoord2s(short x, short y) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 2);
+        growBuffer(TEXTCOORD, 2);
         if(tComps>0) 
             GLBuffers.puts(textCoordArray, x);
         if(tComps>1) 
@@ -581,7 +663,7 @@ public class ImmModeSink {
     }
     public void glTexCoord3s(short x, short y, short z) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 3);
+        growBuffer(TEXTCOORD, 3);
         if(tComps>0) 
             GLBuffers.puts(textCoordArray, x);
         if(tComps>1) 
@@ -592,7 +674,7 @@ public class ImmModeSink {
     }
     public void glTexCoord2f(float x, float y) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 2);
+        growBuffer(TEXTCOORD, 2);
         if(tComps>0) 
             GLBuffers.putf(textCoordArray, x);
         if(tComps>1) 
@@ -601,7 +683,7 @@ public class ImmModeSink {
     }
     public void glTexCoord3f(float x, float y, float z) {
         checkSeal(false);
-        growBufferIfNecessary(TEXTCOORD, 3);
+        growBuffer(TEXTCOORD, 3);
         if(tComps>0) 
             GLBuffers.putf(textCoordArray, x);
         if(tComps>1) 
@@ -629,10 +711,10 @@ public class ImmModeSink {
     public void destroy(GL gl) {
         reset(gl);
 
+        vCount=0; cCount=0; nCount=0; tCount=0;
         vertexArray=null; colorArray=null; normalArray=null; textCoordArray=null;
         vArrayData=null; cArrayData=null; nArrayData=null; tArrayData=null;
         buffer=null;
-        bSize=0; count=0;
     }
 
     public void reset(GL gl) {
@@ -649,8 +731,13 @@ public class ImmModeSink {
         this.mode = 0;
         this.modeOrig = 0;
         this.sealed=false;
+        this.sealedGL=false;
         this.bufferEnabled=false;
         this.bufferWritten=false;
+        this.vElems=0;
+        this.cElems=0;
+        this.nElems=0;
+        this.tElems=0;        
     }
 
     public void seal(GL glObj, boolean seal)
@@ -660,19 +747,25 @@ public class ImmModeSink {
         sealedGL = seal;
         GL gl = glObj.getGL();
         if(seal) {
-            if(vboUsage && vboName==0) {
-                int[] tmp = new int[1];
-                gl.glGenBuffers(1, tmp, 0);
-                vboName = tmp[0];
+            if(useVBO) {
+                if(0 == vboName) {
+                    int[] tmp = new int[1];
+                    gl.glGenBuffers(1, tmp, 0);
+                    vboName = tmp[0];
+                }
+                if(null!=vArrayData) {
+                    vArrayData.setVBOName(vboName);
+                }
+                if(null!=cArrayData) {
+                    cArrayData.setVBOName(vboName);
+                }
+                if(null!=nArrayData) {
+                    nArrayData.setVBOName(vboName);
+                }
+                if(null!=tArrayData) {
+                    tArrayData.setVBOName(vboName);
+                }
             }
-            if(null!=vArrayData)
-                vArrayData.setVBOName(vboName);
-            if(null!=cArrayData)
-                cArrayData.setVBOName(vboName);
-            if(null!=nArrayData)
-                nArrayData.setVBOName(vboName);
-            if(null!=tArrayData)
-                tArrayData.setVBOName(vboName);
             enableBuffer(gl, true);
         } else {
             enableBuffer(gl, false);
@@ -685,68 +778,89 @@ public class ImmModeSink {
         sealed = seal;
         if(seal) {
             bufferWritten=false;
+            rewind();
         }
     }
 
   public void enableBuffer(GL gl, boolean enable) {
-    /* if(enableBufferAlways && enable) {
-        bufferEnabled = false;
-    } */
-    if( bufferEnabled != enable && count>0 ) {
+    if( bufferEnabled != enable && vElems>0 ) {
         if(enable) {
             checkSeal(true);
         }
+        bufferEnabled = enable;
         if(useGLSL) { 
             enableBufferGLSL(gl, enable);
         } else {
             enableBufferFixed(gl, enable);
         }
-        bufferEnabled = enable;
     }
   }
 
   public void enableBufferFixed(GL gl, boolean enable) {
     GL2ES1 glf = gl.getGL2ES1();
+    
+    final boolean useV = vComps>0 && vElems>0 ;
+    final boolean useC = cComps>0 && cElems>0 ;
+    final boolean useN = nComps>0 && nElems>0 ;
+    final boolean useT = tComps>0 && tElems>0 ;
+    
+    if(DEBUG_DRAW) {
+        System.err.println("ImmModeSink.enableFixed.0 "+enable+": use [ v "+useV+", c "+useC+", n "+useN+", t "+useT+"]");        
+    }
 
     if(enable) {
-        gl.glBindBuffer(GL.GL_ARRAY_BUFFER, vboName);
-
-        if(!bufferWritten) {
-            gl.glBufferData(GL.GL_ARRAY_BUFFER, buffer.limit(), buffer, GL.GL_STATIC_DRAW);
-            bufferWritten=true;
+        if(useVBO) {
+            if(0 == vboName) {
+                throw new InternalError("Using VBO but no vboName");
+            }
+            glf.glBindBuffer(GL.GL_ARRAY_BUFFER, vboName);
+            
+            if(!bufferWritten) {
+                glf.glBufferData(GL.GL_ARRAY_BUFFER, buffer.limit(), buffer, glBufferUsage);
+            }
         }
+        bufferWritten=true;
+    }
 
-        if(vComps>0) {
+    if(useV) {
+       if(enable) {
            glf.glEnableClientState(GLPointerFunc.GL_VERTEX_ARRAY);
            glf.glVertexPointer(vArrayData);
-        }
-        if(cComps>0) {
+       } else {
+           glf.glDisableClientState(GLPointerFunc.GL_VERTEX_ARRAY);               
+       }
+    }
+    if(useC) {
+       if(enable) {
            glf.glEnableClientState(GLPointerFunc.GL_COLOR_ARRAY);
            glf.glColorPointer(cArrayData);
-        }
-        if(nComps>0) {
+       } else {
+           glf.glDisableClientState(GLPointerFunc.GL_COLOR_ARRAY);
+       }
+    }
+    if(useN) {
+       if(enable) {
            glf.glEnableClientState(GLPointerFunc.GL_NORMAL_ARRAY);
            glf.glNormalPointer(nArrayData);
-        }
-        if(tComps>0) {
+       } else {
+           glf.glDisableClientState(GLPointerFunc.GL_NORMAL_ARRAY);
+       }
+    }
+    if(useT) {
+       if(enable) {
            glf.glEnableClientState(GLPointerFunc.GL_TEXTURE_COORD_ARRAY);
            glf.glTexCoordPointer(tArrayData);
-        }
+       } else {
+           glf.glDisableClientState(GLPointerFunc.GL_TEXTURE_COORD_ARRAY);
+       }
+    }
 
+    if(enable && useVBO) {
         gl.glBindBuffer(GL.GL_ARRAY_BUFFER, 0);
-    } else {
-        if(vComps>0) {
-           glf.glDisableClientState(GLPointerFunc.GL_VERTEX_ARRAY);
-        }
-        if(cComps>0) {
-           glf.glDisableClientState(GLPointerFunc.GL_COLOR_ARRAY);
-        }
-        if(nComps>0) {
-           glf.glDisableClientState(GLPointerFunc.GL_NORMAL_ARRAY);
-        }
-        if(tComps>0) {
-           glf.glDisableClientState(GLPointerFunc.GL_TEXTURE_COORD_ARRAY);
-        }
+    }
+    
+    if(DEBUG_DRAW) {
+        System.err.println("ImmModeSink.enableFixed.X "+this);        
     }
   }
 
@@ -757,54 +871,79 @@ public class ImmModeSink {
     }      
     GL2ES2 glsl = gl.getGL2ES2();
  
+    final boolean useV = vComps>0 && vElems>0 ;
+    final boolean useC = cComps>0 && cElems>0 ;
+    final boolean useN = nComps>0 && nElems>0 ;
+    final boolean useT = tComps>0 && tElems>0 ;
+    
+    if(DEBUG_DRAW) {
+        System.err.println("ImmModeSink.enableGLSL.0 "+enable+": use [ v "+useV+", c "+useC+", n "+useN+", t "+useT+"]");        
+    }
+    
     if(enable) {
-        glsl.glBindBuffer(GL.GL_ARRAY_BUFFER, vboName);
-
-        if(!bufferWritten) {
-            glsl.glBufferData(GL.GL_ARRAY_BUFFER, buffer.limit(), buffer, GL.GL_STATIC_DRAW);
-            bufferWritten=true;
+        if(useVBO) {
+            if(0 == vboName) {
+                throw new InternalError("Using VBO but no vboName");
+            }
+            glsl.glBindBuffer(GL.GL_ARRAY_BUFFER, vboName);
+            if(!bufferWritten) {
+                glsl.glBufferData(GL.GL_ARRAY_BUFFER, buffer.limit(), buffer, GL.GL_STATIC_DRAW);
+            }
         }
+        bufferWritten=true;
+    }
 
-        if(vComps>0) {
+    if(useV) {
+       if(enable) {
            st.enableVertexAttribArray(glsl, vArrayData);
            st.vertexAttribPointer(glsl, vArrayData);
-        }
-        if(cComps>0) {
+       } else {
+           st.disableVertexAttribArray(glsl, vArrayData);
+       }
+    }
+    if(useC) {
+       if(enable) {
            st.enableVertexAttribArray(glsl, cArrayData);
            st.vertexAttribPointer(glsl, cArrayData);
-        }
-        if(nComps>0) {
+       } else {
+           st.disableVertexAttribArray(glsl, cArrayData);
+       }
+    }
+    if(useN) {
+       if(enable) {
            st.enableVertexAttribArray(glsl, nArrayData);
            st.vertexAttribPointer(glsl, nArrayData);
-        }
-        if(tComps>0) {
+       } else {
+           st.disableVertexAttribArray(glsl, nArrayData);
+       }
+    }
+    if(useT) {
+       if(enable) {
            st.enableVertexAttribArray(glsl, tArrayData);
            st.vertexAttribPointer(glsl, tArrayData);
-        }
-
-        glsl.glBindBuffer(GL.GL_ARRAY_BUFFER, 0);
-    } else {
-        if(vComps>0) {
-           st.disableVertexAttribArray(glsl, vArrayData);
-        }
-        if(cComps>0) {
-           st.disableVertexAttribArray(glsl, cArrayData);
-        }
-        if(nComps>0) {
-           st.disableVertexAttribArray(glsl, nArrayData);
-        }
-        if(tComps>0) {
+       } else {
            st.disableVertexAttribArray(glsl, tArrayData);
-        }
+       }
+    }
+    
+    if(enable && useVBO) {
+        glsl.glBindBuffer(GL.GL_ARRAY_BUFFER, 0);
+    }
+    
+    if(DEBUG_DRAW) {
+        System.err.println("ImmModeSink.enableGLSL.X "+this);        
     }
   }
 
     public String toString() {
         return "VBOSet[mode "+mode+ 
                        ", modeOrig "+modeOrig+ 
+                       ", use/count "+getElemUseCountStr()+
                        ", sealed "+sealed+ 
+                       ", sealedGL "+sealedGL+
                        ", bufferEnabled "+bufferEnabled+ 
-                       ", bufferWritten "+bufferWritten+ 
+                       ", bufferWritten "+bufferWritten+
+                       ", useVBO "+useVBO+", vboName "+vboName+
                        ",\n\t"+vArrayData+
                        ",\n\t"+cArrayData+
                        ",\n\t"+nArrayData+
@@ -814,55 +953,84 @@ public class ImmModeSink {
 
     // non public matters
 
-    protected void allocateBuffer(int elementCount) {
-        int vWidth = vComps * GLBuffers.sizeOfGLType(vDataType);
-        int cWidth = cComps * GLBuffers.sizeOfGLType(cDataType);
-        int nWidth = nComps * GLBuffers.sizeOfGLType(nDataType);
-        int tWidth = tComps * GLBuffers.sizeOfGLType(tDataType);
-
-        count  = elementCount;
-        bSize  = count * ( vWidth + cWidth + nWidth + tWidth ) ;
-
-        buffer = GLBuffers.newDirectByteBuffer(bSize);
-
-        int pos = 0;
-        int size= count * vWidth ;
-        if(size>0) {
-            vertexArray = GLBuffers.sliceGLBuffer(buffer, pos, size, vDataType);
+    protected String getElemUseCountStr() {
+        return "[v "+vElems+"/"+vCount+", c "+cElems+"/"+cCount+", n "+nElems+"/"+nCount+", t "+tElems+"/"+tCount+"]";
+    }
+    
+    protected boolean fitElemsInBuffers(int addElems) {
+        final int vAdd = addElems - ( vCount - vElems );
+        final int cAdd = addElems - ( cCount - cElems );
+        final int nAdd = addElems - ( nCount - nElems );
+        final int tAdd = addElems - ( tCount - tElems );
+        final boolean res = 0>=vAdd && 0>=cAdd && 0>=nAdd && 0>=tAdd;
+        /* if(DEBUG_BUFFER) {
+            System.err.println("ImmModeSink.fitElemsInBuffer: "+getElemUseCountStr()+" + "+addElems+" -> "+res);
+        } */
+        return res;
+    }
+    
+    protected boolean reallocateBuffer(int addElems) {
+        final int vAdd = addElems - ( vCount - vElems );
+        final int cAdd = addElems - ( cCount - cElems );
+        final int nAdd = addElems - ( nCount - nElems );
+        final int tAdd = addElems - ( tCount - tElems );
+        
+        if( 0>=vAdd && 0>=cAdd && 0>=nAdd && 0>=tAdd) {
+            if(DEBUG_BUFFER) {
+                System.err.println("ImmModeSink.realloc: "+getElemUseCountStr()+" + "+addElems+" -> NOP");
+            }
+            return false;
+        }
+        
+        if(DEBUG_BUFFER) {
+            System.err.println("ImmModeSink.realloc: "+getElemUseCountStr()+" + "+addElems);
+        }
+        vCount += vAdd;
+        cCount += cAdd;
+        nCount += nAdd;
+        tCount += tAdd;
+        
+        final int vWidth = vComps * GLBuffers.sizeOfGLType(vDataType);
+        final int cWidth = cComps * GLBuffers.sizeOfGLType(cDataType);
+        final int nWidth = nComps * GLBuffers.sizeOfGLType(nDataType);
+        final int tWidth = tComps * GLBuffers.sizeOfGLType(tDataType);
+
+        final int bSizeV  = vCount * vWidth;
+        final int bSizeC  = cCount * cWidth;
+        final int bSizeN  = nCount * nWidth;
+        final int bSizeT  = tCount * tWidth;
+        
+        buffer = GLBuffers.newDirectByteBuffer( bSizeV + bSizeC + bSizeN + bSizeT );
+        vOffset = 0;
+        
+        if(bSizeV>0) {
+            vertexArray = GLBuffers.sliceGLBuffer(buffer, vOffset, bSizeV, vDataType);
         } else {
             vertexArray = null;
-        }
-        vOffset = pos;
-        pos+=size;
+        }        
+        cOffset=vOffset+bSizeV;
 
-        size= count * cWidth ;
-        if(size>0) {
-            colorArray = GLBuffers.sliceGLBuffer(buffer, pos, size, cDataType);
+        if(bSizeC>0) {
+            colorArray = GLBuffers.sliceGLBuffer(buffer, cOffset, bSizeC, cDataType);
         } else {
             colorArray = null;
         }
-        cOffset = pos;
-        pos+=size;
+        nOffset=cOffset+bSizeC;
 
-        size= count * nWidth ;
-        if(size>0) {
-            normalArray = GLBuffers.sliceGLBuffer(buffer, pos, size, nDataType);
+        if(bSizeN>0) {
+            normalArray = GLBuffers.sliceGLBuffer(buffer, nOffset, bSizeN, nDataType);
         } else {
             normalArray = null;
         }
-        nOffset = pos;
-        pos+=size;
+        tOffset=nOffset+bSizeN;
 
-        size= count * tWidth ;
-        if(size>0) {
-            textCoordArray = GLBuffers.sliceGLBuffer(buffer, pos, size, tDataType);
+        if(bSizeT>0) {
+            textCoordArray = GLBuffers.sliceGLBuffer(buffer, tOffset, bSizeT, tDataType);
         } else {
             textCoordArray = null;
         }
-        tOffset = pos;
-        pos+=size;
 
-        buffer.position(pos);
+        buffer.position(tOffset+bSizeT);
         buffer.flip();
 
         if(vComps>0) {
@@ -889,41 +1057,42 @@ public class ImmModeSink {
         } else {
             tArrayData = null;
         }
-
-    }
-
-    protected final boolean growBufferIfNecessary(int type, int spare) {
-        if(buffer==null || count < spare) { 
-            growBuffer(type, initialElementCount);
-            return true;
+        
+        if(DEBUG_BUFFER) {
+            System.err.println("ImmModeSink.realloc.X: "+this.toString());
+            Thread.dumpStack();
         }
-        return false;
+        return true;
     }
 
-    protected final void growBuffer(int type, int additional) {
-        if(sealed || 0==additional) return;
-
-        // save olde values ..
-        Buffer _vertexArray=vertexArray, _colorArray=colorArray, _normalArray=normalArray, _textCoordArray=textCoordArray;
-
-        allocateBuffer(count+additional);
-
-        if(null!=_vertexArray) {
-            _vertexArray.flip();
-            GLBuffers.put(vertexArray, _vertexArray);
-        }
-        if(null!=_colorArray) {
-            _colorArray.flip();
-            GLBuffers.put(colorArray, _colorArray);
-        }
-        if(null!=_normalArray) {
-            _normalArray.flip();
-            GLBuffers.put(normalArray, _normalArray);
-        }
-        if(null!=_textCoordArray) {
-            _textCoordArray.flip();
-            GLBuffers.put(textCoordArray, _textCoordArray);
+    protected final boolean growBuffer(int type, int additional) {
+        if( null !=buffer && !sealed && 0<additional) {
+            if( !fitElemsInBuffers(additional) ) {
+                // save olde values ..
+                final Buffer _vertexArray=vertexArray, _colorArray=colorArray, _normalArray=normalArray, _textCoordArray=textCoordArray;
+        
+                if ( reallocateBuffer(initialElementCount) ) {
+                    if(null!=_vertexArray) {
+                        _vertexArray.flip();
+                        GLBuffers.put(vertexArray, _vertexArray);
+                    }
+                    if(null!=_colorArray) {
+                        _colorArray.flip();
+                        GLBuffers.put(colorArray, _colorArray);
+                    }
+                    if(null!=_normalArray) {
+                        _normalArray.flip();
+                        GLBuffers.put(normalArray, _normalArray);
+                    }
+                    if(null!=_textCoordArray) {
+                        _textCoordArray.flip();
+                        GLBuffers.put(textCoordArray, _textCoordArray);
+                    }
+                    return true;
+                }
+            }
         }
+        return false;
     }
 
     protected void padding(int type, int fill) {
@@ -934,15 +1103,19 @@ public class ImmModeSink {
         switch (type) {
             case VERTEX:
                 dest = vertexArray;
+                vElems++;
                 break;
             case COLOR:
                 dest = colorArray;
+                cElems++;
                 break;
             case NORMAL:
                 dest = normalArray;
+                nElems++;
                 break;
             case TEXTCOORD:
                 dest = textCoordArray;
+                tElems++;
                 break;
         }
 
@@ -953,26 +1126,28 @@ public class ImmModeSink {
         }
     }
 
+    final protected int glBufferUsage, initialElementCount;
+    final protected boolean useVBO;
     protected int mode, modeOrig;
-    protected int glBufferUsage, initialElementCount;
 
     protected ByteBuffer buffer;
-    protected int bSize, count, vboName;
+    protected int vboName;
 
     public static final int VERTEX = 0;
     public static final int COLOR = 1;
     public static final int NORMAL = 2;
     public static final int TEXTCOORD = 3;
 
-    protected int vOffset, cOffset, nOffset, tOffset;
+    protected int vCount,    cCount,    nCount,    tCount;
+    protected int vOffset,   cOffset,   nOffset,   tOffset;
     protected int vComps,    cComps,    nComps,    tComps;
+    protected int vElems,    cElems,    nElems,    tElems;
     protected int vDataType, cDataType, nDataType, tDataType;
     protected Buffer vertexArray, colorArray, normalArray, textCoordArray;
     protected GLArrayDataWrapper vArrayData, cArrayData, nArrayData, tArrayData;
 
     protected boolean sealed, sealedGL, useGLSL;
     protected boolean bufferEnabled, bufferWritten;
-    protected GL gl;
   }
 
 }