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- triangulation: re-introduce special handling for quads, now with proper support for concave quads. This should *really* fix [3429812], but it leaves me to suspect bugs in the general-purpose triangulation code for ngons.

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git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@1341 67173fc5-114c-0410-ac8e-9d2fd5bffc1f
This commit is contained in:
aramis_acg
2012-11-29 15:25:09 +00:00
parent 477995f860
commit ddea19ead1
3 changed files with 63 additions and 7 deletions
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50
code/TriangulateProcess.cpp
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@@ -188,6 +188,8 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh)
FILE* fout = fopen(POLY_OUTPUT_FILE,"a");
#endif
const aiVector3D* verts = pMesh->mVertices;
// use boost::scoped_array to avoid slow std::vector<bool> specialiations
boost::scoped_array<bool> done(new bool[max_out]);
for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
@@ -216,24 +218,59 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh)
face.mIndices = NULL;
continue;
} /* does not handle concave quads
}
// optimized code for quadrilaterals
else if ( face.mNumIndices == 4) {
// quads can have at maximum one concave vertex. Determine
// this vertex (if it exists) and start tri-fanning from
// it.
unsigned int start_vertex = 0;
for (unsigned int i = 0; i < 4; ++i) {
const aiVector3D& v0 = verts[face.mIndices[(i+3) % 4]];
const aiVector3D& v1 = verts[face.mIndices[(i+2) % 4]];
const aiVector3D& v2 = verts[face.mIndices[(i+1) % 4]];
const aiVector3D& v = verts[face.mIndices[i]];
aiVector3D left = (v0-v);
aiVector3D diag = (v1-v);
aiVector3D right = (v2-v);
left.Normalize();
diag.Normalize();
right.Normalize();
const float angle = acos(left*diag) + acos(right*diag);
if (angle > AI_MATH_PI_F) {
// this is the concave point
start_vertex = i;
break;
}
}
const unsigned int temp[] = {face.mIndices[0], face.mIndices[1], face.mIndices[2], face.mIndices[3]};
aiFace& nface = *curOut++;
nface.mNumIndices = 3;
nface.mIndices = face.mIndices;
nface.mIndices[0] = temp[start_vertex];
nface.mIndices[1] = temp[(start_vertex + 1) % 4];
nface.mIndices[2] = temp[(start_vertex + 2) % 4];
aiFace& sface = *curOut++;
sface.mNumIndices = 3;
sface.mIndices = new unsigned int[3];
sface.mIndices[0] = face.mIndices[0];
sface.mIndices[1] = face.mIndices[2];
sface.mIndices[2] = face.mIndices[3];
sface.mIndices[0] = temp[start_vertex];
sface.mIndices[1] = temp[(start_vertex + 2) % 4];
sface.mIndices[2] = temp[(start_vertex + 3) % 4];
// prevent double deletion of the indices field
face.mIndices = NULL;
continue;
} */
}
else
{
// A polygon with more than 3 vertices can be either concave or convex.
@@ -246,7 +283,6 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh)
// We project it onto a plane to get a 2d triangle.
// Collect all vertices of of the polygon.
const aiVector3D* verts = pMesh->mVertices;
for (tmp = 0; tmp < max; ++tmp) {
temp_verts3d[tmp] = verts[idx[tmp]];
}