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/** @file Implementation of the DeterminePTypeHelperProcess and
 *  SortByPTypeProcess post-process steps.
*/



// internal headers
#include "ProcessHelper.h"
#include "SortByPTypeProcess.h"
#include <assimp/Exceptional.h>

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
SortByPTypeProcess::SortByPTypeProcess()
: mConfigRemoveMeshes( 0 ) {
    // empty
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
SortByPTypeProcess::~SortByPTypeProcess()
{
    // nothing to do here
}

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool SortByPTypeProcess::IsActive( unsigned int pFlags) const
{
    return  (pFlags & aiProcess_SortByPType) != 0;
}

// ------------------------------------------------------------------------------------------------
void SortByPTypeProcess::SetupProperties(const Importer* pImp)
{
    mConfigRemoveMeshes = pImp->GetPropertyInteger(AI_CONFIG_PP_SBP_REMOVE,0);
}

// ------------------------------------------------------------------------------------------------
// Update changed meshes in all nodes
void UpdateNodes(const std::vector<unsigned int>& replaceMeshIndex, aiNode* node)
{
    if (node->mNumMeshes)
    {
        unsigned int newSize = 0;
        for (unsigned int m = 0; m< node->mNumMeshes; ++m)
        {
            unsigned int add = node->mMeshes[m]<<2;
            for (unsigned int i = 0; i < 4;++i)
            {
                if (UINT_MAX != replaceMeshIndex[add+i])++newSize;
            }
        }
        if (!newSize)
        {
            delete[] node->mMeshes;
            node->mNumMeshes = 0;
            node->mMeshes    = NULL;
        }
        else
        {
            // Try to reuse the old array if possible
            unsigned int* newMeshes = (newSize > node->mNumMeshes
                ? new unsigned int[newSize] : node->mMeshes);

            for (unsigned int m = 0; m< node->mNumMeshes; ++m)
            {
                unsigned int add = node->mMeshes[m]<<2;
                for (unsigned int i = 0; i < 4;++i)
                {
                    if (UINT_MAX != replaceMeshIndex[add+i])
                        *newMeshes++ = replaceMeshIndex[add+i];
                }
            }
            if (newSize > node->mNumMeshes)
                delete[] node->mMeshes;

            node->mMeshes = newMeshes-(node->mNumMeshes = newSize);
        }
    }

    // call all subnodes recursively
    for (unsigned int m = 0; m < node->mNumChildren; ++m)
        UpdateNodes(replaceMeshIndex,node->mChildren[m]);
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void SortByPTypeProcess::Execute( aiScene* pScene) {
    if ( 0 == pScene->mNumMeshes) {
        ASSIMP_LOG_DEBUG("SortByPTypeProcess skipped, there are no meshes");
        return;
    }

    ASSIMP_LOG_DEBUG("SortByPTypeProcess begin");

    unsigned int aiNumMeshesPerPType[4] = {0,0,0,0};

    std::vector<aiMesh*> outMeshes;
    outMeshes.reserve(pScene->mNumMeshes<<1u);

    bool bAnyChanges = false;

    std::vector<unsigned int> replaceMeshIndex(pScene->mNumMeshes*4,UINT_MAX);
    std::vector<unsigned int>::iterator meshIdx = replaceMeshIndex.begin();
    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
        aiMesh* const mesh = pScene->mMeshes[i];
        ai_assert(0 != mesh->mPrimitiveTypes);

        // if there's just one primitive type in the mesh there's nothing to do for us
        unsigned int num = 0;
        if (mesh->mPrimitiveTypes & aiPrimitiveType_POINT) {
            ++aiNumMeshesPerPType[0];
            ++num;
        }
        if (mesh->mPrimitiveTypes & aiPrimitiveType_LINE) {
            ++aiNumMeshesPerPType[1];
            ++num;
        }
        if (mesh->mPrimitiveTypes & aiPrimitiveType_TRIANGLE) {
            ++aiNumMeshesPerPType[2];
            ++num;
        }
        if (mesh->mPrimitiveTypes & aiPrimitiveType_POLYGON) {
            ++aiNumMeshesPerPType[3];
            ++num;
        }

        if (1 == num) {
            if (!(mConfigRemoveMeshes & mesh->mPrimitiveTypes)) {
                *meshIdx = static_cast<unsigned int>( outMeshes.size() );
                outMeshes.push_back(mesh);
            } else {
                delete mesh;
                pScene->mMeshes[ i ] = nullptr;
                bAnyChanges = true;
            }

            meshIdx += 4;
            continue;
        }
        bAnyChanges = true;

        // reuse our current mesh arrays for the submesh
        // with the largest number of primitives
        unsigned int aiNumPerPType[4] = {0,0,0,0};
        aiFace* pFirstFace = mesh->mFaces;
        aiFace* const pLastFace = pFirstFace + mesh->mNumFaces;

        unsigned int numPolyVerts = 0;
        for (;pFirstFace != pLastFace; ++pFirstFace) {
            if (pFirstFace->mNumIndices <= 3)
                ++aiNumPerPType[pFirstFace->mNumIndices-1];
            else
            {
                ++aiNumPerPType[3];
                numPolyVerts += pFirstFace-> mNumIndices;
            }
        }

        VertexWeightTable* avw = ComputeVertexBoneWeightTable(mesh);
        for (unsigned int real = 0; real < 4; ++real,++meshIdx)
        {
            if ( !aiNumPerPType[real] || mConfigRemoveMeshes & (1u << real))
            {
                continue;
            }

            *meshIdx = (unsigned int) outMeshes.size();
            outMeshes.push_back(new aiMesh());
            aiMesh* out = outMeshes.back();

            // the name carries the adjacency information between the meshes
            out->mName = mesh->mName;

            // copy data members
            out->mPrimitiveTypes = 1u << real;
            out->mMaterialIndex = mesh->mMaterialIndex;

            // allocate output storage
            out->mNumFaces = aiNumPerPType[real];
            aiFace* outFaces = out->mFaces = new aiFace[out->mNumFaces];

            out->mNumVertices = (3 == real ? numPolyVerts : out->mNumFaces * (real+1));

            aiVector3D *vert(nullptr), *nor(nullptr), *tan(nullptr), *bit(nullptr);
            aiVector3D *uv   [AI_MAX_NUMBER_OF_TEXTURECOORDS];
            aiColor4D  *cols [AI_MAX_NUMBER_OF_COLOR_SETS];

            if (mesh->mVertices) {
                vert = out->mVertices = new aiVector3D[out->mNumVertices];
            }

            if (mesh->mNormals) {
                nor = out->mNormals = new aiVector3D[out->mNumVertices];
            }

            if (mesh->mTangents) {
                tan = out->mTangents   = new aiVector3D[out->mNumVertices];
                bit = out->mBitangents = new aiVector3D[out->mNumVertices];
            }

            for (unsigned int j = 0; j < AI_MAX_NUMBER_OF_TEXTURECOORDS;++j) {
                uv[j] = nullptr;
                if (mesh->mTextureCoords[j]) {
                    uv[j] = out->mTextureCoords[j] = new aiVector3D[out->mNumVertices];
                }

                out->mNumUVComponents[j] = mesh->mNumUVComponents[j];
            }

            for (unsigned int j = 0; j < AI_MAX_NUMBER_OF_COLOR_SETS;++j) {
                cols[j] = nullptr;
                if (mesh->mColors[j]) {
                    cols[j] = out->mColors[j] = new aiColor4D[out->mNumVertices];
                }
            }

            typedef std::vector< aiVertexWeight > TempBoneInfo;
            std::vector< TempBoneInfo > tempBones(mesh->mNumBones);

            // try to guess how much storage we'll need
            for (unsigned int q = 0; q < mesh->mNumBones;++q)
            {
                tempBones[q].reserve(mesh->mBones[q]->mNumWeights / (num-1));
            }

            unsigned int outIdx = 0;
            for (unsigned int m = 0; m < mesh->mNumFaces; ++m)
            {
                aiFace& in = mesh->mFaces[m];
                if ((real == 3  && in.mNumIndices <= 3) || (real != 3 && in.mNumIndices != real+1))
                {
                    continue;
                }

                outFaces->mNumIndices = in.mNumIndices;
                outFaces->mIndices    = in.mIndices;

                for (unsigned int q = 0; q < in.mNumIndices; ++q)
                {
                    unsigned int idx = in.mIndices[q];

                    // process all bones of this index
                    if (avw)
                    {
                        VertexWeightTable& tbl = avw[idx];
                        for (VertexWeightTable::const_iterator it = tbl.begin(), end = tbl.end();
                             it != end; ++it)
                        {
                            tempBones[ (*it).first ].push_back( aiVertexWeight(outIdx, (*it).second) );
                        }
                    }

                    if (vert)
                    {
                        *vert++ = mesh->mVertices[idx];
                        //mesh->mVertices[idx].x = get_qnan();
                    }
                    if (nor )*nor++  = mesh->mNormals[idx];
                    if (tan )
                    {
                        *tan++  = mesh->mTangents[idx];
                        *bit++  = mesh->mBitangents[idx];
                    }

                    for (unsigned int pp = 0; pp < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++pp)
                    {
                        if (!uv[pp])break;
                        *uv[pp]++ = mesh->mTextureCoords[pp][idx];
                    }

                    for (unsigned int pp = 0; pp < AI_MAX_NUMBER_OF_COLOR_SETS; ++pp)
                    {
                        if (!cols[pp])break;
                        *cols[pp]++ = mesh->mColors[pp][idx];
                    }

                    in.mIndices[q] = outIdx++;
                }

                in.mIndices = nullptr;
                ++outFaces;
            }
            ai_assert(outFaces == out->mFaces + out->mNumFaces);

            // now generate output bones
			for (unsigned int q = 0; q < mesh->mNumBones; ++q) {
				if (!tempBones[q].empty()) {
					++out->mNumBones;
				}
			}

            if (out->mNumBones) {
                out->mBones = new aiBone*[out->mNumBones];
                for (unsigned int q = 0, boneIdx = 0; q < mesh->mNumBones;++q)
                {
                    TempBoneInfo& in = tempBones[q];
					if (in.empty()) {
						continue;
					}

                    aiBone* srcBone = mesh->mBones[q];
					aiBone *bone = out->mBones[boneIdx] = new aiBone();

                    bone->mName = srcBone->mName;
                    bone->mOffsetMatrix = srcBone->mOffsetMatrix;

                    bone->mNumWeights = (unsigned int)in.size();
                    bone->mWeights = new aiVertexWeight[bone->mNumWeights];

                    ::memcpy(bone->mWeights,&in[0],bone->mNumWeights*sizeof(aiVertexWeight));

                    ++boneIdx;
                }
            }
        }

        // delete the per-vertex bone weights table
        delete[] avw;

        // delete the input mesh
        delete mesh;

        // avoid invalid pointer
        pScene->mMeshes[i] = nullptr;
    }

    if (outMeshes.empty())
    {
        // This should not occur
        throw DeadlyImportError("No meshes remaining");
    }

    // If we added at least one mesh process all nodes in the node
    // graph and update their respective mesh indices.
    if (bAnyChanges)
    {
        UpdateNodes(replaceMeshIndex,pScene->mRootNode);
    }

    if (outMeshes.size() != pScene->mNumMeshes)
    {
        delete[] pScene->mMeshes;
        pScene->mNumMeshes = (unsigned int)outMeshes.size();
        pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
    }
    ::memcpy(pScene->mMeshes,&outMeshes[0],pScene->mNumMeshes*sizeof(void*));

    if (!DefaultLogger::isNullLogger())
    {
        char buffer[1024];
        ::ai_snprintf(buffer,1024,"Points: %u%s, Lines: %u%s, Triangles: %u%s, Polygons: %u%s (Meshes, X = removed)",
            aiNumMeshesPerPType[0], ((mConfigRemoveMeshes & aiPrimitiveType_POINT)     ? "X" : ""),
            aiNumMeshesPerPType[1], ((mConfigRemoveMeshes & aiPrimitiveType_LINE)      ? "X" : ""),
            aiNumMeshesPerPType[2], ((mConfigRemoveMeshes & aiPrimitiveType_TRIANGLE)  ? "X" : ""),
            aiNumMeshesPerPType[3], ((mConfigRemoveMeshes & aiPrimitiveType_POLYGON)   ? "X" : ""));
        ASSIMP_LOG_INFO(buffer);
        ASSIMP_LOG_DEBUG("SortByPTypeProcess finished");
    }
}

