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Diffstat (limited to 'src/jogl/classes/jogamp/opengl/glu/tessellator/TessMono.java')
| -rw-r--r-- | src/jogl/classes/jogamp/opengl/glu/tessellator/TessMono.java | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/jogl/classes/jogamp/opengl/glu/tessellator/TessMono.java b/src/jogl/classes/jogamp/opengl/glu/tessellator/TessMono.java new file mode 100644 index 000000000..ef89b1613 --- /dev/null +++ b/src/jogl/classes/jogamp/opengl/glu/tessellator/TessMono.java @@ -0,0 +1,241 @@ +/* +* Portions Copyright (C) 2003-2006 Sun Microsystems, Inc. +* All rights reserved. +*/ + +/* +** 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 2.0 (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. +** +** NOTE: The Original Code (as defined below) has been licensed to Sun +** Microsystems, Inc. ("Sun") under the SGI Free Software License B +** (Version 1.1), shown above ("SGI License"). Pursuant to Section +** 3.2(3) of the SGI License, Sun is distributing the Covered Code to +** you under an alternative license ("Alternative License"). This +** Alternative License includes all of the provisions of the SGI License +** except that Section 2.2 and 11 are omitted. Any differences between +** the Alternative License and the SGI License are offered solely by Sun +** and not by SGI. +** +** 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. +** +** Author: Eric Veach, July 1994 +** Java Port: Pepijn Van Eeckhoudt, July 2003 +** Java Port: Nathan Parker Burg, August 2003 +*/ +package com.jogamp.opengl.impl.glu.tessellator; + +class TessMono { +/* __gl_meshTessellateMonoRegion( face ) tessellates a monotone region + * (what else would it do??) The region must consist of a single + * loop of half-edges (see mesh.h) oriented CCW. "Monotone" in this + * case means that any vertical line intersects the interior of the + * region in a single interval. + * + * Tessellation consists of adding interior edges (actually pairs of + * half-edges), to split the region into non-overlapping triangles. + * + * The basic idea is explained in Preparata and Shamos (which I don''t + * have handy right now), although their implementation is more + * complicated than this one. The are two edge chains, an upper chain + * and a lower chain. We process all vertices from both chains in order, + * from right to left. + * + * The algorithm ensures that the following invariant holds after each + * vertex is processed: the untessellated region consists of two + * chains, where one chain (say the upper) is a single edge, and + * the other chain is concave. The left vertex of the single edge + * is always to the left of all vertices in the concave chain. + * + * Each step consists of adding the rightmost unprocessed vertex to one + * of the two chains, and forming a fan of triangles from the rightmost + * of two chain endpoints. Determining whether we can add each triangle + * to the fan is a simple orientation test. By making the fan as large + * as possible, we restore the invariant (check it yourself). + */ + static boolean __gl_meshTessellateMonoRegion(GLUface face, boolean avoidDegenerateTris) { + GLUhalfEdge up, lo; + + /* All edges are oriented CCW around the boundary of the region. + * First, find the half-edge whose origin vertex is rightmost. + * Since the sweep goes from left to right, face->anEdge should + * be close to the edge we want. + */ + up = face.anEdge; + assert (up.Lnext != up && up.Lnext.Lnext != up); + + for (; Geom.VertLeq(up.Sym.Org, up.Org); up = up.Onext.Sym) + ; + for (; Geom.VertLeq(up.Org, up.Sym.Org); up = up.Lnext) + ; + lo = up.Onext.Sym; + + boolean mustConnect = false; // hack for avoidDegenerateTris + + while (up.Lnext != lo) { + if (avoidDegenerateTris && !mustConnect) { + // Skip over regions where several vertices are collinear, + // to try to avoid producing degenerate (zero-area) triangles + // + // The "mustConnect" flag is a hack to try to avoid + // skipping too large regions and causing incorrect + // triangulations. This entire modification is overall + // not robust and needs more work + if (Geom.EdgeCos(lo.Lnext.Org, lo.Org, lo.Lnext.Lnext.Org) <= -Geom.ONE_MINUS_EPSILON) { + // Lines around lo + do { + lo = lo.Onext.Sym; + mustConnect = true; + } while (up.Lnext != lo && + Geom.EdgeCos(lo.Lnext.Org, lo.Org, lo.Lnext.Lnext.Org) <= -Geom.ONE_MINUS_EPSILON); + } else if (Geom.EdgeCos(up.Onext.Sym.Org, up.Org, up.Onext.Sym.Onext.Sym.Org) <= -Geom.ONE_MINUS_EPSILON) { + // Lines around up + do { + up = up.Lnext; + mustConnect = true; + } while (up.Lnext != lo && + Geom.EdgeCos(up.Onext.Sym.Org, up.Org, up.Onext.Sym.Onext.Sym.Org) <= -Geom.ONE_MINUS_EPSILON); + } + + if (up.Lnext == lo) + break; + } + + if (Geom.VertLeq(up.Sym.Org, lo.Org)) { + /* up.Sym.Org is on the left. It is safe to form triangles from lo.Org. + * The EdgeGoesLeft test guarantees progress even when some triangles + * are CW, given that the upper and lower chains are truly monotone. + */ + while (lo.Lnext != up && (Geom.EdgeGoesLeft(lo.Lnext) + || Geom.EdgeSign(lo.Org, lo.Sym.Org, lo.Lnext.Sym.Org) <= 0)) { + GLUhalfEdge tempHalfEdge = Mesh.__gl_meshConnect(lo.Lnext, lo); + mustConnect = false; + if (tempHalfEdge == null) return false; + lo = tempHalfEdge.Sym; + } + lo = lo.Onext.Sym; + } else { + /* lo.Org is on the left. We can make CCW triangles from up.Sym.Org. */ + while (lo.Lnext != up && (Geom.EdgeGoesRight(up.Onext.Sym) + || Geom.EdgeSign(up.Sym.Org, up.Org, up.Onext.Sym.Org) >= 0)) { + GLUhalfEdge tempHalfEdge = Mesh.__gl_meshConnect(up, up.Onext.Sym); + mustConnect = false; + if (tempHalfEdge == null) return false; + up = tempHalfEdge.Sym; + } + up = up.Lnext; + } + } + + /* Now lo.Org == up.Sym.Org == the leftmost vertex. The remaining region + * can be tessellated in a fan from this leftmost vertex. + */ + assert (lo.Lnext != up); + while (lo.Lnext.Lnext != up) { + GLUhalfEdge tempHalfEdge = Mesh.__gl_meshConnect(lo.Lnext, lo); + if (tempHalfEdge == null) return false; + lo = tempHalfEdge.Sym; + } + + return true; + } + + +/* __gl_meshTessellateInterior( mesh ) tessellates each region of + * the mesh which is marked "inside" the polygon. Each such region + * must be monotone. + */ + public static boolean __gl_meshTessellateInterior(GLUmesh mesh, boolean avoidDegenerateTris) { + GLUface f, next; + + /*LINTED*/ + for (f = mesh.fHead.next; f != mesh.fHead; f = next) { + /* Make sure we don''t try to tessellate the new triangles. */ + next = f.next; + if (f.inside) { + if (!__gl_meshTessellateMonoRegion(f, avoidDegenerateTris)) return false; + } + } + + return true; + } + + +/* __gl_meshDiscardExterior( mesh ) zaps (ie. sets to NULL) all faces + * which are not marked "inside" the polygon. Since further mesh operations + * on NULL faces are not allowed, the main purpose is to clean up the + * mesh so that exterior loops are not represented in the data structure. + */ + public static void __gl_meshDiscardExterior(GLUmesh mesh) { + GLUface f, next; + + /*LINTED*/ + for (f = mesh.fHead.next; f != mesh.fHead; f = next) { + /* Since f will be destroyed, save its next pointer. */ + next = f.next; + if (!f.inside) { + Mesh.__gl_meshZapFace(f); + } + } + } + + private static final int MARKED_FOR_DELETION = 0x7fffffff; + +/* __gl_meshSetWindingNumber( mesh, value, keepOnlyBoundary ) resets the + * winding numbers on all edges so that regions marked "inside" the + * polygon have a winding number of "value", and regions outside + * have a winding number of 0. + * + * If keepOnlyBoundary is TRUE, it also deletes all edges which do not + * separate an interior region from an exterior one. + */ + public static boolean __gl_meshSetWindingNumber(GLUmesh mesh, int value, boolean keepOnlyBoundary) { + GLUhalfEdge e, eNext; + + for (e = mesh.eHead.next; e != mesh.eHead; e = eNext) { + eNext = e.next; + if (e.Sym.Lface.inside != e.Lface.inside) { + + /* This is a boundary edge (one side is interior, one is exterior). */ + e.winding = (e.Lface.inside) ? value : -value; + } else { + + /* Both regions are interior, or both are exterior. */ + if (!keepOnlyBoundary) { + e.winding = 0; + } else { + if (!Mesh.__gl_meshDelete(e)) return false; + } + } + } + return true; + } + +} |