diff options
Diffstat (limited to 'src/classes/com/sun/opengl')
3 files changed, 67 insertions, 4 deletions
diff --git a/src/classes/com/sun/opengl/impl/glu/tessellator/GLUtessellatorImpl.java b/src/classes/com/sun/opengl/impl/glu/tessellator/GLUtessellatorImpl.java index 4f36c7018..f4efb116a 100644 --- a/src/classes/com/sun/opengl/impl/glu/tessellator/GLUtessellatorImpl.java +++ b/src/classes/com/sun/opengl/impl/glu/tessellator/GLUtessellatorImpl.java @@ -85,6 +85,10 @@ public class GLUtessellatorImpl implements GLUtessellator { boolean flagBoundary; /* mark boundary edges (use EdgeFlag) */ boolean boundaryOnly; /* Extract contours, not triangles */ + boolean avoidDegenerateTris; /* JOGL-specific hint to try to improve triangulation + by avoiding producing degenerate (zero-area) triangles; + has not been tested exhaustively and is therefore an option */ + GLUface lonelyTriList; /* list of triangles which could not be rendered as strips or fans */ @@ -234,6 +238,10 @@ public class GLUtessellatorImpl implements GLUtessellator { boundaryOnly = (value != 0); return; + case GLU.GLU_TESS_AVOID_DEGENERATE_TRIANGLES: + avoidDegenerateTris = (value != 0); + return; + default: callErrorOrErrorData(GLU.GLU_INVALID_ENUM); return; @@ -261,6 +269,9 @@ public class GLUtessellatorImpl implements GLUtessellator { assert (boundaryOnly == true || boundaryOnly == false); value[value_offset] = boundaryOnly ? 1 : 0; break; + case GLU.GLU_TESS_AVOID_DEGENERATE_TRIANGLES: + value[value_offset] = avoidDegenerateTris ? 1 : 0; + break; default: value[value_offset] = 0.0; callErrorOrErrorData(GLU.GLU_INVALID_ENUM); @@ -526,7 +537,7 @@ public class GLUtessellatorImpl implements GLUtessellator { if (boundaryOnly) { rc = TessMono.__gl_meshSetWindingNumber(mesh, 1, true); } else { - rc = TessMono.__gl_meshTessellateInterior(mesh); + rc = TessMono.__gl_meshTessellateInterior(mesh, avoidDegenerateTris); } if (!rc) throw new RuntimeException(); /* could've used a label */ diff --git a/src/classes/com/sun/opengl/impl/glu/tessellator/Geom.java b/src/classes/com/sun/opengl/impl/glu/tessellator/Geom.java index 6b31cc30e..1287a60e0 100644 --- a/src/classes/com/sun/opengl/impl/glu/tessellator/Geom.java +++ b/src/classes/com/sun/opengl/impl/glu/tessellator/Geom.java @@ -315,4 +315,24 @@ class Geom { static double VertL1dist(GLUvertex u, GLUvertex v) { return Math.abs(u.s - v.s) + Math.abs(u.t - v.t); } + + /***********************************************************************/ + + // Compute the cosine of the angle between the edges between o and + // v1 and between o and v2 + static double EdgeCos(GLUvertex o, GLUvertex v1, GLUvertex v2) { + double ov1s = v1.s - o.s; + double ov1t = v1.t - o.t; + double ov2s = v2.s - o.s; + double ov2t = v2.t - o.t; + double dotp = ov1s * ov2s + ov1t * ov2t; + double len = Math.sqrt(ov1s * ov1s + ov1t * ov1t) * Math.sqrt(ov2s * ov2s + ov2t * ov2t); + if (len > 0.0) { + dotp /= len; + } + return dotp; + } + + static final double EPSILON = 1.0e-5; + static final double ONE_MINUS_EPSILON = 1.0 - EPSILON; } diff --git a/src/classes/com/sun/opengl/impl/glu/tessellator/TessMono.java b/src/classes/com/sun/opengl/impl/glu/tessellator/TessMono.java index 62c653bfe..fe0f7946c 100644 --- a/src/classes/com/sun/opengl/impl/glu/tessellator/TessMono.java +++ b/src/classes/com/sun/opengl/impl/glu/tessellator/TessMono.java @@ -80,7 +80,7 @@ class TessMono { * 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) { + static boolean __gl_meshTessellateMonoRegion(GLUface face, boolean avoidDegenerateTris) { GLUhalfEdge up, lo; /* All edges are oriented CCW around the boundary of the region. @@ -97,7 +97,37 @@ class TessMono { ; 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 @@ -106,6 +136,7 @@ class TessMono { 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; } @@ -115,6 +146,7 @@ class TessMono { 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; } @@ -140,7 +172,7 @@ class TessMono { * the mesh which is marked "inside" the polygon. Each such region * must be monotone. */ - public static boolean __gl_meshTessellateInterior(GLUmesh mesh) { + public static boolean __gl_meshTessellateInterior(GLUmesh mesh, boolean avoidDegenerateTris) { GLUface f, next; /*LINTED*/ @@ -148,7 +180,7 @@ class TessMono { /* Make sure we don''t try to tessellate the new triangles. */ next = f.next; if (f.inside) { - if (!__gl_meshTessellateMonoRegion(f)) return false; + if (!__gl_meshTessellateMonoRegion(f, avoidDegenerateTris)) return false; } } |