Method TriangulateMesh

code/PostProcessing/TriangulateProcess.cpp:206–505

------------------------------------------------------------------------------------------------ Triangulates the given mesh.

// ------------------------------------------------------------------------------------------------
// Triangulates the given mesh.
bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh) {
    // Now we have aiMesh::mPrimitiveTypes, so this is only here for test cases
    if (!pMesh->mPrimitiveTypes)    {
        bool bNeed = false;

        for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
            const aiFace& face = pMesh->mFaces[a];
            if( face.mNumIndices != 3)  {
                bNeed = true;
            }
        }
        if (!bNeed) {
            return false;
        }
    }
    else if (!(pMesh->mPrimitiveTypes & aiPrimitiveType_POLYGON)) {
        return false;
    }

    // Find out how many output faces we'll get
    uint32_t numOut = 0, max_out = 0;
    bool get_normals = true;
    for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
        aiFace& face = pMesh->mFaces[a];
        if (face.mNumIndices <= 4) {
            get_normals = false;
        }
        if( face.mNumIndices <= 3) {
            ++numOut;
        } else {
            numOut += face.mNumIndices-2;
            max_out = std::max<uint32_t>(max_out,face.mNumIndices);
        }
    }

    // Just another check whether aiMesh::mPrimitiveTypes is correct
    if (numOut == pMesh->mNumFaces) {
        ASSIMP_LOG_ERROR( "Invalidation detected in the number of indices: does not fit to the primitive type." );
        return false;
    }

    aiVector3D *nor_out = nullptr;

    // if we don't have normals yet, but expect them to be a cheap side
    // product of triangulation anyway, allocate storage for them.
    if (!pMesh->mNormals && get_normals) {
        // XXX need a mechanism to inform the GenVertexNormals process to treat these normals as preprocessed per-face normals
    //  nor_out = pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
    }

    // the output mesh will contain triangles, but no polys anymore
    pMesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
    pMesh->mPrimitiveTypes &= ~aiPrimitiveType_POLYGON;

    // The mesh becomes NGON encoded now, during the triangulation process.
    pMesh->mPrimitiveTypes |= aiPrimitiveType_NGONEncodingFlag;

    aiFace* out = new aiFace[numOut](), *curOut = out;