fix stupid degenerate triangle check, I don't have a clue what I was

thinking when I wrote it

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@8671 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/model_shared.c b/model_shared.c
index 911d3fca2c3fa9ce1a0413d8af01a75052f8669b..381eb71f5a47993ae1a701d0fd48817033c1a051 100644 (file)
--- a/model_shared.c
+++ b/model_shared.c
@@ -2105,23 +2105,20 @@ void Mod_SnapVertices(int numcomponents, int numvertices, float *vertices, float
 int Mod_RemoveDegenerateTriangles(int numtriangles, const int *inelement3i, int *outelement3i, const float *vertex3f)
 {
        int i, outtriangles;
-       float d, edgedir[3], temp[3];
+       float d, edgedir1[3], edgedir2[3], temp[3];
        // a degenerate triangle is one with no width (thickness, surface area)
        // these are characterized by having all 3 points colinear (along a line)
        // or having two points identical
+       // the simplest check is to calculate the triangle's area
        for (i = 0, outtriangles = 0;i < numtriangles;i++, inelement3i += 3)
        {
                // calculate first edge
-               VectorSubtract(vertex3f + inelement3i[1] * 3, vertex3f + inelement3i[0] * 3, edgedir);
-               if (VectorLength2(edgedir) < 0.0001f)
-                       continue; // degenerate first edge (no length)
-               VectorNormalize(edgedir);
-               // check if third point is on the edge (colinear)
-               d = -DotProduct(vertex3f + inelement3i[2] * 3, edgedir);
-               VectorMA(vertex3f + inelement3i[2] * 3, d, edgedir, temp);
-               if (VectorLength2(temp) < 0.0001f)
-                       continue; // third point colinear with first edge
-               // valid triangle (no colinear points, no duplicate points)
+               VectorSubtract(vertex3f + inelement3i[1] * 3, vertex3f + inelement3i[0] * 3, edgedir1);
+               VectorSubtract(vertex3f + inelement3i[1] * 3, vertex3f + inelement3i[0] * 3, edgedir2);
+               CrossProduct(edgedir1, edgedir2, temp);
+               if (VectorLength2(temp) < 0.001f)
+                       continue; // degenerate triangle (no area)
+               // valid triangle (has area)
                VectorCopy(inelement3i, outelement3i);
                outelement3i += 3;
                outtriangles++;