C++ SpatialSort::FindPositions方法代码示例

//.........这里部分代码省略.........
		// store for every vertex of that face
		for( unsigned int b = 0; b < face.mNumIndices; b++)
		{
			unsigned int p = face.mIndices[b];

			// project tangent and bitangent into the plane formed by the vertex' normal
			aiVector3D localTangent = tangent - meshNorm[p] * (tangent * meshNorm[p]);
			aiVector3D localBitangent = bitangent - meshNorm[p] * (bitangent * meshNorm[p]);
			localTangent.Normalize(); localBitangent.Normalize();

			// and write it into the mesh.
			meshTang[p] = localTangent;
			meshBitang[p] = localBitangent;
		}
    }


	// create a helper to quickly find locally close vertices among the vertex array
	// FIX: check whether we can reuse the SpatialSort of a previous step
	SpatialSort* vertexFinder = NULL;
	SpatialSort  _vertexFinder;
	float posEpsilon;
	if (shared)
	{
		std::vector<std::pair<SpatialSort,float> >* avf;
		shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
		if (avf)
		{
			std::pair<SpatialSort,float>& blubb = avf->operator [] (meshIndex);
			vertexFinder = &blubb.first;
			posEpsilon = blubb.second;;
		}
	}
	if (!vertexFinder)
	{
		_vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
		vertexFinder = &_vertexFinder;
		posEpsilon = ComputePositionEpsilon(pMesh);
	}
	std::vector<unsigned int> verticesFound;

	const float fLimit = cosf(configMaxAngle); 
	std::vector<unsigned int> closeVertices;

	// in the second pass we now smooth out all tangents and bitangents at the same local position 
	// if they are not too far off.
	for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
	{
		if( vertexDone[a])
			continue;

		const aiVector3D& origPos = pMesh->mVertices[a];
		const aiVector3D& origNorm = pMesh->mNormals[a];
		const aiVector3D& origTang = pMesh->mTangents[a];
		const aiVector3D& origBitang = pMesh->mBitangents[a];
		closeVertices.clear();

		// find all vertices close to that position
		vertexFinder->FindPositions( origPos, posEpsilon, verticesFound);

		closeVertices.reserve (verticesFound.size()+5);
		closeVertices.push_back( a);

		// look among them for other vertices sharing the same normal and a close-enough tangent/bitangent
		for( unsigned int b = 0; b < verticesFound.size(); b++)
		{
			unsigned int idx = verticesFound[b];
			if( vertexDone[idx])
				continue;
			if( meshNorm[idx] * origNorm < angleEpsilon)
				continue;
			if(  meshTang[idx] * origTang < fLimit)
				continue;
			if( meshBitang[idx] * origBitang < fLimit)
				continue;

			// it's similar enough -> add it to the smoothing group
			closeVertices.push_back( idx);
			vertexDone[idx] = true;
		}

		// smooth the tangents and bitangents of all vertices that were found to be close enough
		aiVector3D smoothTangent( 0, 0, 0), smoothBitangent( 0, 0, 0);
		for( unsigned int b = 0; b < closeVertices.size(); ++b)
		{
			smoothTangent += meshTang[ closeVertices[b] ];
			smoothBitangent += meshBitang[ closeVertices[b] ];
		}
		smoothTangent.Normalize();
		smoothBitangent.Normalize();

		// and write it back into all affected tangents
		for( unsigned int b = 0; b < closeVertices.size(); ++b)
		{
			meshTang[ closeVertices[b] ] = smoothTangent;
			meshBitang[ closeVertices[b] ] = smoothBitangent;
		}
	}
	return true;
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
bool GenVertexNormalsProcess::GenMeshVertexNormals (aiMesh* pMesh, unsigned int meshIndex)
{
    if (NULL != pMesh->mNormals)
        return false;

    // If the mesh consists of lines and/or points but not of
    // triangles or higher-order polygons the normal vectors
    // are undefined.
    if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON)))
    {
        ASSIMP_LOG_INFO("Normal vectors are undefined for line and point meshes");
        return false;
    }

    // Allocate the array to hold the output normals
    const float qnan = std::numeric_limits<ai_real>::quiet_NaN();
    pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];

    // Compute per-face normals but store them per-vertex
    for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
    {
        const aiFace& face = pMesh->mFaces[a];
        if (face.mNumIndices < 3)
        {
            // either a point or a line -> no normal vector
            for (unsigned int i = 0;i < face.mNumIndices;++i) {
                pMesh->mNormals[face.mIndices[i]] = aiVector3D(qnan);
            }

            continue;
        }

        const aiVector3D* pV1 = &pMesh->mVertices[face.mIndices[0]];
        const aiVector3D* pV2 = &pMesh->mVertices[face.mIndices[1]];
        const aiVector3D* pV3 = &pMesh->mVertices[face.mIndices[face.mNumIndices-1]];
        const aiVector3D vNor = ((*pV2 - *pV1) ^ (*pV3 - *pV1)).NormalizeSafe();

        for (unsigned int i = 0;i < face.mNumIndices;++i) {
            pMesh->mNormals[face.mIndices[i]] = vNor;
        }
    }

    // Set up a SpatialSort to quickly find all vertices close to a given position
    // check whether we can reuse the SpatialSort of a previous step.
    SpatialSort* vertexFinder = NULL;
    SpatialSort  _vertexFinder;
    ai_real posEpsilon = ai_real( 1e-5 );
    if (shared) {
        std::vector<std::pair<SpatialSort,ai_real> >* avf;
        shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
        if (avf)
        {
            std::pair<SpatialSort,ai_real>& blubb = avf->operator [] (meshIndex);
            vertexFinder = &blubb.first;
            posEpsilon = blubb.second;
        }
    }
    if (!vertexFinder)  {
        _vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
        vertexFinder = &_vertexFinder;
        posEpsilon = ComputePositionEpsilon(pMesh);
    }
    std::vector<unsigned int> verticesFound;
    aiVector3D* pcNew = new aiVector3D[pMesh->mNumVertices];

    if (configMaxAngle >= AI_DEG_TO_RAD( 175.f ))   {
        // There is no angle limit. Thus all vertices with positions close
        // to each other will receive the same vertex normal. This allows us
        // to optimize the whole algorithm a little bit ...
        std::vector<bool> abHad(pMesh->mNumVertices,false);
        for (unsigned int i = 0; i < pMesh->mNumVertices;++i)   {
            if (abHad[i]) {
                continue;
            }

            // Get all vertices that share this one ...
            vertexFinder->FindPositions( pMesh->mVertices[i], posEpsilon, verticesFound);

            aiVector3D pcNor;
            for (unsigned int a = 0; a < verticesFound.size(); ++a) {
                const aiVector3D& v = pMesh->mNormals[verticesFound[a]];
                if (is_not_qnan(v.x))pcNor += v;
            }
            pcNor.NormalizeSafe();

            // Write the smoothed normal back to all affected normals
            for (unsigned int a = 0; a < verticesFound.size(); ++a)
            {
                unsigned int vidx = verticesFound[a];
                pcNew[vidx] = pcNor;
                abHad[vidx] = true;
            }
        }
    }
    // Slower code path if a smooth angle is set. There are many ways to achieve
    // the effect, this one is the most straightforward one.
    else    {
        const ai_real fLimit = std::cos(configMaxAngle);
//.........这里部分代码省略.........