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*/
/** @file Implementation of the post processing step "MakeVerboseFormat"
*/

#include "MakeVerboseFormat.h"
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void MakeVerboseFormatProcess::Execute(aiScene *pScene) {
    ai_assert(nullptr != pScene);
    ASSIMP_LOG_DEBUG("MakeVerboseFormatProcess begin");

    bool bHas = false;
    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
        if (MakeVerboseFormat(pScene->mMeshes[a]))
            bHas = true;
    }
    if (bHas) {
        ASSIMP_LOG_INFO("MakeVerboseFormatProcess finished. There was much work to do ...");
    } else {
        ASSIMP_LOG_DEBUG("MakeVerboseFormatProcess. There was nothing to do.");
    }

    pScene->mFlags &= ~AI_SCENE_FLAGS_NON_VERBOSE_FORMAT;
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
bool MakeVerboseFormatProcess::MakeVerboseFormat(aiMesh *pcMesh) {
    ai_assert(nullptr != pcMesh);

    unsigned int iOldNumVertices = pcMesh->mNumVertices;
    const unsigned int iNumVerts = pcMesh->mNumFaces * 3;

    aiVector3D *pvPositions = new aiVector3D[iNumVerts];

    aiVector3D *pvNormals = nullptr;
    if (pcMesh->HasNormals()) {
        pvNormals = new aiVector3D[iNumVerts];
    }
    aiVector3D *pvTangents = nullptr, *pvBitangents = nullptr;
    if (pcMesh->HasTangentsAndBitangents()) {
        pvTangents = new aiVector3D[iNumVerts];
        pvBitangents = new aiVector3D[iNumVerts];
    }

    aiVector3D *apvTextureCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS] = { nullptr };
    aiColor4D *apvColorSets[AI_MAX_NUMBER_OF_COLOR_SETS] = { nullptr };

    unsigned int p = 0;
    while (pcMesh->HasTextureCoords(p))
        apvTextureCoords[p++] = new aiVector3D[iNumVerts];

    p = 0;
    while (pcMesh->HasVertexColors(p))
        apvColorSets[p++] = new aiColor4D[iNumVerts];

    // allocate enough memory to hold output bones and vertex weights ...
    std::vector<aiVertexWeight> *newWeights = new std::vector<aiVertexWeight>[pcMesh->mNumBones];
    for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
        newWeights[i].reserve(pcMesh->mBones[i]->mNumWeights * 3);
    }

    // iterate through all faces and build a clean list
    unsigned int iIndex = 0;
    for (unsigned int a = 0; a < pcMesh->mNumFaces; ++a) {
        aiFace *pcFace = &pcMesh->mFaces[a];
        for (unsigned int q = 0; q < pcFace->mNumIndices; ++q, ++iIndex) {
            // need to build a clean list of bones, too
            for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
                for (unsigned int boneIdx = 0; boneIdx < pcMesh->mBones[i]->mNumWeights; ++boneIdx) {
                    const aiVertexWeight &w = pcMesh->mBones[i]->mWeights[boneIdx];
                    if (pcFace->mIndices[q] == w.mVertexId) {
                        aiVertexWeight wNew;
                        wNew.mVertexId = iIndex;
                        wNew.mWeight = w.mWeight;
                        newWeights[i].push_back(wNew);
                    }
                }
            }

            pvPositions[iIndex] = pcMesh->mVertices[pcFace->mIndices[q]];

            if (pcMesh->HasNormals()) {
                pvNormals[iIndex] = pcMesh->mNormals[pcFace->mIndices[q]];
            }
            if (pcMesh->HasTangentsAndBitangents()) {
                pvTangents[iIndex] = pcMesh->mTangents[pcFace->mIndices[q]];
                pvBitangents[iIndex] = pcMesh->mBitangents[pcFace->mIndices[q]];
            }

            unsigned int pp = 0;
            while (pcMesh->HasTextureCoords(pp)) {
                apvTextureCoords[pp][iIndex] = pcMesh->mTextureCoords[pp][pcFace->mIndices[q]];
                ++pp;
            }
            pp = 0;
            while (pcMesh->HasVertexColors(pp)) {
                apvColorSets[pp][iIndex] = pcMesh->mColors[pp][pcFace->mIndices[q]];
                ++pp;
            }
            pcFace->mIndices[q] = iIndex;
        }
    }

    // build output vertex weights
    for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
        delete[] pcMesh->mBones[i]->mWeights;
        if (!newWeights[i].empty()) {
            pcMesh->mBones[i]->mWeights = new aiVertexWeight[newWeights[i].size()];
            pcMesh->mBones[i]->mNumWeights = static_cast<unsigned int>(newWeights[i].size());
            aiVertexWeight *weightToCopy = &(newWeights[i][0]);
            memcpy(pcMesh->mBones[i]->mWeights, weightToCopy,
                    sizeof(aiVertexWeight) * newWeights[i].size());
        } else {
            pcMesh->mBones[i]->mWeights = nullptr;
        }
    }
    delete[] newWeights;

    // delete the old members
    delete[] pcMesh->mVertices;
    pcMesh->mVertices = pvPositions;

    p = 0;
    while (pcMesh->HasTextureCoords(p)) {
        delete[] pcMesh->mTextureCoords[p];
        pcMesh->mTextureCoords[p] = apvTextureCoords[p];
        ++p;
    }
    p = 0;
    while (pcMesh->HasVertexColors(p)) {
        delete[] pcMesh->mColors[p];
        pcMesh->mColors[p] = apvColorSets[p];
        ++p;
    }
    pcMesh->mNumVertices = iNumVerts;

    if (pcMesh->HasNormals()) {
        delete[] pcMesh->mNormals;
        pcMesh->mNormals = pvNormals;
    }
    if (pcMesh->HasTangentsAndBitangents()) {
        delete[] pcMesh->mTangents;
        pcMesh->mTangents = pvTangents;
        delete[] pcMesh->mBitangents;
        pcMesh->mBitangents = pvBitangents;
    }
    return (pcMesh->mNumVertices != iOldNumVertices);
}

// ------------------------------------------------------------------------------------------------
bool IsMeshInVerboseFormat(const aiMesh *mesh) {
    // avoid slow vector<bool> specialization
    std::vector<unsigned int> seen(mesh->mNumVertices, 0);
    for (unsigned int i = 0; i < mesh->mNumFaces; ++i) {
        const aiFace &f = mesh->mFaces[i];
        for (unsigned int j = 0; j < f.mNumIndices; ++j) {
            if (++seen[f.mIndices[j]] == 2) {
                // found a duplicate index
                return false;
            }
        }
    }

    return true;
}

// ------------------------------------------------------------------------------------------------
bool MakeVerboseFormatProcess::IsVerboseFormat(const aiScene *pScene) {
    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
        if (!IsMeshInVerboseFormat(pScene->mMeshes[i])) {
            return false;
        }
    }

    return true;
}
