| /* |
| --------------------------------------------------------------------------- |
| Open Asset Import Library (assimp) |
| --------------------------------------------------------------------------- |
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| Copyright (c) 2006-2017, assimp team |
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| */ |
| |
| /** @file Implementation of the post processing step to calculate |
| * tangents and bitangents for all imported meshes |
| */ |
| |
| // internal headers |
| #include "CalcTangentsProcess.h" |
| #include "ProcessHelper.h" |
| #include "TinyFormatter.h" |
| #include "qnan.h" |
| |
| using namespace Assimp; |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Constructor to be privately used by Importer |
| CalcTangentsProcess::CalcTangentsProcess() |
| : configMaxAngle( AI_DEG_TO_RAD(45.f) ) |
| , configSourceUV( 0 ) { |
| // nothing to do here |
| } |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Destructor, private as well |
| CalcTangentsProcess::~CalcTangentsProcess() |
| { |
| // nothing to do here |
| } |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Returns whether the processing step is present in the given flag field. |
| bool CalcTangentsProcess::IsActive( unsigned int pFlags) const |
| { |
| return (pFlags & aiProcess_CalcTangentSpace) != 0; |
| } |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Executes the post processing step on the given imported data. |
| void CalcTangentsProcess::SetupProperties(const Importer* pImp) |
| { |
| ai_assert( NULL != pImp ); |
| |
| // get the current value of the property |
| configMaxAngle = pImp->GetPropertyFloat(AI_CONFIG_PP_CT_MAX_SMOOTHING_ANGLE,45.f); |
| configMaxAngle = std::max(std::min(configMaxAngle,45.0f),0.0f); |
| configMaxAngle = AI_DEG_TO_RAD(configMaxAngle); |
| |
| configSourceUV = pImp->GetPropertyInteger(AI_CONFIG_PP_CT_TEXTURE_CHANNEL_INDEX,0); |
| } |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Executes the post processing step on the given imported data. |
| void CalcTangentsProcess::Execute( aiScene* pScene) |
| { |
| ai_assert( NULL != pScene ); |
| |
| DefaultLogger::get()->debug("CalcTangentsProcess begin"); |
| |
| bool bHas = false; |
| for ( unsigned int a = 0; a < pScene->mNumMeshes; a++ ) { |
| if(ProcessMesh( pScene->mMeshes[a],a))bHas = true; |
| } |
| |
| if ( bHas ) { |
| DefaultLogger::get()->info("CalcTangentsProcess finished. Tangents have been calculated"); |
| } else { |
| DefaultLogger::get()->debug("CalcTangentsProcess finished"); |
| } |
| } |
| |
| // ------------------------------------------------------------------------------------------------ |
| // Calculates tangents and bi-tangents for the given mesh |
| bool CalcTangentsProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshIndex) |
| { |
| // we assume that the mesh is still in the verbose vertex format where each face has its own set |
| // of vertices and no vertices are shared between faces. Sadly I don't know any quick test to |
| // assert() it here. |
| // assert( must be verbose, dammit); |
| |
| if (pMesh->mTangents) // this implies that mBitangents is also there |
| 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))) |
| { |
| DefaultLogger::get()->info("Tangents are undefined for line and point meshes"); |
| return false; |
| } |
| |
| // what we can check, though, is if the mesh has normals and texture coordinates. That's a requirement |
| if( pMesh->mNormals == NULL) |
| { |
| DefaultLogger::get()->error("Failed to compute tangents; need normals"); |
| return false; |
| } |
| if( configSourceUV >= AI_MAX_NUMBER_OF_TEXTURECOORDS || !pMesh->mTextureCoords[configSourceUV] ) |
| { |
| DefaultLogger::get()->error((Formatter::format("Failed to compute tangents; need UV data in channel"),configSourceUV)); |
| return false; |
| } |
| |
| const float angleEpsilon = 0.9999f; |
| |
| std::vector<bool> vertexDone( pMesh->mNumVertices, false); |
| const float qnan = get_qnan(); |
| |
| // create space for the tangents and bitangents |
| pMesh->mTangents = new aiVector3D[pMesh->mNumVertices]; |
| pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices]; |
| |
| const aiVector3D* meshPos = pMesh->mVertices; |
| const aiVector3D* meshNorm = pMesh->mNormals; |
| const aiVector3D* meshTex = pMesh->mTextureCoords[configSourceUV]; |
| aiVector3D* meshTang = pMesh->mTangents; |
| aiVector3D* meshBitang = pMesh->mBitangents; |
| |
| // calculate the tangent and bitangent for every face |
| for( unsigned int a = 0; a < pMesh->mNumFaces; a++) |
| { |
| const aiFace& face = pMesh->mFaces[a]; |
| if (face.mNumIndices < 3) |
| { |
| // There are less than three indices, thus the tangent vector |
| // is not defined. We are finished with these vertices now, |
| // their tangent vectors are set to qnan. |
| for (unsigned int i = 0; i < face.mNumIndices;++i) |
| { |
| unsigned int idx = face.mIndices[i]; |
| vertexDone [idx] = true; |
| meshTang [idx] = aiVector3D(qnan); |
| meshBitang [idx] = aiVector3D(qnan); |
| } |
| |
| continue; |
| } |
| |
| // triangle or polygon... we always use only the first three indices. A polygon |
| // is supposed to be planar anyways.... |
| // FIXME: (thom) create correct calculation for multi-vertex polygons maybe? |
| const unsigned int p0 = face.mIndices[0], p1 = face.mIndices[1], p2 = face.mIndices[2]; |
| |
| // position differences p1->p2 and p1->p3 |
| aiVector3D v = meshPos[p1] - meshPos[p0], w = meshPos[p2] - meshPos[p0]; |
| |
| // texture offset p1->p2 and p1->p3 |
| float sx = meshTex[p1].x - meshTex[p0].x, sy = meshTex[p1].y - meshTex[p0].y; |
| float tx = meshTex[p2].x - meshTex[p0].x, ty = meshTex[p2].y - meshTex[p0].y; |
| float dirCorrection = (tx * sy - ty * sx) < 0.0f ? -1.0f : 1.0f; |
| // when t1, t2, t3 in same position in UV space, just use default UV direction. |
| if ( 0 == sx && 0 ==sy && 0 == tx && 0 == ty ) { |
| sx = 0.0; sy = 1.0; |
| tx = 1.0; ty = 0.0; |
| } |
| |
| // tangent points in the direction where to positive X axis of the texture coord's would point in model space |
| // bitangent's points along the positive Y axis of the texture coord's, respectively |
| aiVector3D tangent, bitangent; |
| tangent.x = (w.x * sy - v.x * ty) * dirCorrection; |
| tangent.y = (w.y * sy - v.y * ty) * dirCorrection; |
| tangent.z = (w.z * sy - v.z * ty) * dirCorrection; |
| bitangent.x = (w.x * sx - v.x * tx) * dirCorrection; |
| bitangent.y = (w.y * sx - v.y * tx) * dirCorrection; |
| bitangent.z = (w.z * sx - v.z * tx) * dirCorrection; |
| |
| // 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(); |
| |
| // reconstruct tangent/bitangent according to normal and bitangent/tangent when it's infinite or NaN. |
| bool invalid_tangent = is_special_float(localTangent.x) || is_special_float(localTangent.y) || is_special_float(localTangent.z); |
| bool invalid_bitangent = is_special_float(localBitangent.x) || is_special_float(localBitangent.y) || is_special_float(localBitangent.z); |
| if (invalid_tangent != invalid_bitangent) { |
| if (invalid_tangent) { |
| localTangent = meshNorm[p] ^ localBitangent; |
| localTangent.Normalize(); |
| } else { |
| localBitangent = localTangent ^ meshNorm[p]; |
| 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 = std::cos(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.resize( 0 ); |
| |
| // 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; |
| } |
