archive/blender-archive
Archived
1
1
Fork 0
Code Pull Requests Packages Activity

Made another attempt to fix degenerate triangles in imported mesh data.

Browse Source 
This commit replaces the solution in revision 44539.

It is recalled that a degenerate triangle is a triangle such that
1) A and B are in the same position in the 3D space; or
2) the distance between point P and line segment AB is zero.

Degenerate triangles in the second form are now resolved by adding a
small offset to P (i.e., the resulting triangles have a non-zero area).
This commit is contained in:
Tamito Kajiyama
2012-03-03 01:03:20 +00:00
parent 35708fe150
commit 00782aae1f
1 changed files with 69 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

123
source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
View File

@@ -486,23 +486,26 @@ void BlenderFileLoader::insertShapeNode(ObjectInstanceRen *obi, int id)
delete [] VIndices;
delete [] NIndices;
// Removal of degenerate triangles
// Fix for degenerated triangles
// A degenerate triangle is a triangle such that
// 1) A and B are in the same position in the 3D space; or
// 2) the distance between point P and line segment AB is zero.
// Only those degenerate triangles in the second form are addressed here
// (by transforming them into the first form). Those in the first form
// are addressed later in WShape::MakeFace().
unsigned vi0, vi1, vi2, vi;
unsigned ni0, ni1, ni2, ni;
unsigned numDetris = 0;
// Only those degenerate triangles in the second form are resolved here
// by adding a small offset to P, whereas those in the first form are
// addressed later in WShape::MakeFace().
typedef struct {
unsigned viA, viB, viP; // 0 <= viA, viB, viP < viSize
Vec3r v;
unsigned n;
} detri_t;
vector<detri_t> detriList;
Vec3r zero(0.0, 0.0, 0.0);
unsigned vi0, vi1, vi2;
for (i = 0; i < viSize; i += 3) {
detri_t detri;
vi0 = cleanVIndices[i];
vi1 = cleanVIndices[i+1];
vi2 = cleanVIndices[i+2];
ni0 = cleanNIndices[i];
ni1 = cleanNIndices[i+1];
ni2 = cleanNIndices[i+2];
Vec3r v0(cleanVertices[vi0], cleanVertices[vi0+1], cleanVertices[vi0+2]);
Vec3r v1(cleanVertices[vi1], cleanVertices[vi1+1], cleanVertices[vi1+2]);
Vec3r v2(cleanVertices[vi2], cleanVertices[vi2+1], cleanVertices[vi2+2]);
@@ -510,57 +513,69 @@ void BlenderFileLoader::insertShapeNode(ObjectInstanceRen *obi, int id)
// do nothing for now
}
else if (GeomUtils::distPointSegment<Vec3r>(v0, v1, v2) < 1e-6) {
if ((v1-v0).squareNorm() < (v2-v0).squareNorm()) {
vi = vi1;
ni = ni1;
} else {
vi = vi2;
ni = ni2;
}
cleanVertices[vi0] = cleanVertices[vi];
cleanVertices[vi0+1] = cleanVertices[vi+1];
cleanVertices[vi0+2] = cleanVertices[vi+2];
cleanNormals[ni0] = cleanNormals[ni];
cleanNormals[ni0+1] = cleanNormals[ni+1];
cleanNormals[ni0+2] = cleanNormals[ni+2];
++numDetris;
detri.viP = vi0; detri.viA = vi1; detri.viB = vi2;
}
else if (GeomUtils::distPointSegment<Vec3r>(v1, v0, v2) < 1e-6) {
if ((v0-v1).squareNorm() < (v2-v1).squareNorm()) {
vi = vi0;
ni = ni0;
} else {
vi = vi2;
ni = ni2;
}
cleanVertices[vi1] = cleanVertices[vi];
cleanVertices[vi1+1] = cleanVertices[vi+1];
cleanVertices[vi1+2] = cleanVertices[vi+2];
cleanNormals[ni1] = cleanNormals[ni];
cleanNormals[ni1+1] = cleanNormals[ni+1];
cleanNormals[ni1+2] = cleanNormals[ni+2];
++numDetris;
detri.viP = vi1; detri.viA = vi0; detri.viB = vi2;
}
else if (GeomUtils::distPointSegment<Vec3r>(v2, v0, v1) < 1e-6) {
if ((v0-v2).squareNorm() < (v1-v2).squareNorm()) {
vi = vi0;
ni = ni0;
} else {
vi = vi1;
ni = ni1;
}
cleanVertices[vi2] = cleanVertices[vi];
cleanVertices[vi2+1] = cleanVertices[vi+1];
cleanVertices[vi2+2] = cleanVertices[vi+2];
cleanNormals[ni2] = cleanNormals[ni];
cleanNormals[ni2+1] = cleanNormals[ni+1];
cleanNormals[ni2+2] = cleanNormals[ni+2];
++numDetris;
detri.viP = vi2; detri.viA = vi0; detri.viB = vi1;
}
else {
continue;
}
detri.v = zero;
detri.n = 0;
for (unsigned j = 0; j < viSize; j += 3) {
if (i == j)
continue;
vi0 = cleanVIndices[j];
vi1 = cleanVIndices[j+1];
vi2 = cleanVIndices[j+2];
Vec3r v0(cleanVertices[vi0], cleanVertices[vi0+1], cleanVertices[vi0+2]);
Vec3r v1(cleanVertices[vi1], cleanVertices[vi1+1], cleanVertices[vi1+2]);
Vec3r v2(cleanVertices[vi2], cleanVertices[vi2+1], cleanVertices[vi2+2]);
if (detri.viP == vi0 && (detri.viA == vi1 || detri.viB == vi1)) {
detri.v += (v2 - v0);
detri.n++;
} else if (detri.viP == vi0 && (detri.viA == vi2 || detri.viB == vi2)) {
detri.v += (v1 - v0);
detri.n++;
} else if (detri.viP == vi1 && (detri.viA == vi0 || detri.viB == vi0)) {
detri.v += (v2 - v1);
detri.n++;
} else if (detri.viP == vi1 && (detri.viA == vi2 || detri.viB == vi2)) {
detri.v += (v0 - v1);
detri.n++;
} else if (detri.viP == vi2 && (detri.viA == vi0 || detri.viB == vi0)) {
detri.v += (v1 - v2);
detri.n++;
} else if (detri.viP == vi2 && (detri.viA == vi1 || detri.viB == vi1)) {
detri.v += (v0 - v2);
detri.n++;
}
}
if (detri.n > 0) {
detri.v.normalizeSafe();
}
detriList.push_back(detri);
}
if (numDetris > 0) {
if (detriList.size() > 0) {
vector<detri_t>::iterator v;
for (v = detriList.begin(); v != detriList.end(); v++) {
detri_t detri = (*v);
if (detri.n == 0) {
cleanVertices[detri.viP] = cleanVertices[detri.viA];
cleanVertices[detri.viP+1] = cleanVertices[detri.viA+1];
cleanVertices[detri.viP+2] = cleanVertices[detri.viA+2];
} else if (detri.v.norm() > 0.0) {
cleanVertices[detri.viP] += 1e-5 * detri.v.x();
cleanVertices[detri.viP+1] += 1e-5 * detri.v.y();
cleanVertices[detri.viP+2] += 1e-5 * detri.v.z();
}
}
printf("Warning: Object %s contains %d degenerate triangle%s (strokes may be incorrect)\n",
name, numDetris, (numDetris > 1) ? "s" : "");
name, detriList.size(), (detriList.size() > 1) ? "s" : "");
}
// Create the IndexedFaceSet with the retrieved attributes