diff options
| author | Clement Jacob <clems71@gmail.com> | 2021-03-29 19:03:01 +0200 |
|---|---|---|
| committer | Clement Jacob <clems71@gmail.com> | 2021-03-30 09:10:50 +0200 |
| commit | 596001c89c672f2dc559e040693c95a893d6907c (patch) | |
| tree | e94538aa121ac176366da5b511c2c2a0fb924ba1 /code/PostProcessing/TriangulateProcess.cpp | |
| parent | 81019d5e589833d86686acdf4c42a36d6aad622e (diff) | |
Refactoring the extension
Diffstat (limited to 'code/PostProcessing/TriangulateProcess.cpp')
| -rw-r--r-- | code/PostProcessing/TriangulateProcess.cpp | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/code/PostProcessing/TriangulateProcess.cpp b/code/PostProcessing/TriangulateProcess.cpp index 00a55e35d..c982d9292 100644 --- a/code/PostProcessing/TriangulateProcess.cpp +++ b/code/PostProcessing/TriangulateProcess.cpp @@ -195,6 +195,13 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) const aiVector3D* verts = pMesh->mVertices; + // NGON encoding note: making sure that triangles are not recognized as false ngons. + // To do so, we make sure the first indice of the new emitted triangle is not the same as previous one. + unsigned int prev_first_indice = (unsigned int)-1; + + // The mesh becomes NGON encoded now, during the triangulation process. + pMesh->mPrimitiveTypes |= aiPrimitiveType_NGONEncodingFlag; + // use std::unique_ptr to avoid slow std::vector<bool> specialiations std::unique_ptr<bool[]> done(new bool[max_out]); for( unsigned int a = 0; a < pMesh->mNumFaces; a++) { @@ -214,24 +221,12 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) aiFace* const last_face = curOut; - // ngon encoding: making sure that triangles are not recognized as false ngons. - // To do so, we make sure the first indice is not the same as previous triangle emitted. - unsigned int prev_first_indice = (unsigned int)-1; - if (curOut != out) prev_first_indice = (curOut - 1)->mIndices[0]; - // if it's a simple point,line or triangle: just copy it if( face.mNumIndices <= 3) { aiFace& nface = *curOut++; nface.mNumIndices = face.mNumIndices; nface.mIndices = face.mIndices; - - if (nface.mIndices[0] == prev_first_indice) { - // rotate indices to avoid ngon encoding false ngons - std::swap(nface.mIndices[0], nface.mIndices[2]); - std::swap(nface.mIndices[1], nface.mIndices[2]); - } - face.mIndices = nullptr; continue; } @@ -242,7 +237,7 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) // this vertex (if it exists) and start tri-fanning from // it. // - // Due to ngon encoding, if this concave vertex is the same as the previously + // Due to NGON encoding, if this concave vertex is the same as the previously // emitted triangle, we use the opposite vertex which also happens to work // for tri-fanning a concave quad. // ref: https://github.com/assimp/assimp/pull/3695#issuecomment-805999760 @@ -265,7 +260,7 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) const float angle = std::acos(left*diag) + std::acos(right*diag); if (angle > AI_MATH_PI_F) { - // i is the concave point + // this is the concave point start_vertex = i; break; } @@ -306,11 +301,11 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) // modeling suite to make extensive use of highly concave, monster polygons ... // so we need to apply the full 'ear cutting' algorithm to get it right. - // RERQUIREMENT: polygon is expected to be simple and *nearly* planar. + // REQUIREMENT: polygon is expected to be simple and *nearly* planar. // We project it onto a plane to get a 2d triangle. // Collect all vertices of of the polygon. - for (tmp = 0; tmp < max; ++tmp) { + for (tmp = 0; tmp < max; ++tmp) { temp_verts3d[tmp] = verts[idx[tmp]]; } @@ -530,6 +525,17 @@ bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) i[0] = idx[i[0]]; i[1] = idx[i[1]]; i[2] = idx[i[2]]; + + // NGON encoding: only quads are supported. + // For everything else, we make sure we don't emit 'false' ngons. We thus avoid having + // 2 consecutive triangles with their first index identical. + if (face.mNumIndices != 4 && i[0] == prev_first_indice) { + // rotate indices + std::swap(i[0], i[2]); + std::swap(i[1], i[2]); + } + + prev_first_indice = i[0]; ++f; } |