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/** @file  SMDLoader.cpp
 *  @brief Implementation of the SMD importer class
 */


#ifndef ASSIMP_BUILD_NO_SMD_IMPORTER

#include <assimp/fast_atof.h>
#include <assimp/SkeletonMeshBuilder.h>
#include <assimp/Importer.hpp>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/importerdesc.h>
#include <memory>
#include <assimp/DefaultIOSystem.h>
#include <tuple>

// internal headers
#include "SMDLoader.h"

#ifndef _MSC_VER
#define strtok_s strtok_r
#endif

namespace Assimp {

static constexpr aiImporterDesc desc = {
    "Valve SMD Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportTextFlavour,
    0,
    0,
    0,
    0,
    "smd vta"
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
SMDImporter::SMDImporter() :
        configFrameID(),
        mBuffer(),
        mEnd(nullptr),
        pScene(nullptr),
        iFileSize( 0 ),
        iSmallestFrame( INT_MAX ),
        dLengthOfAnim( 0.0 ),
        bHasUVs(false ),
        iLineNumber((unsigned int)-1)  {
    // empty
}


// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool SMDImporter::CanRead( const std::string& filename, IOSystem* /*pIOHandler*/, bool) const {
    return SimpleExtensionCheck(filename, "smd", "vta");
}

// ------------------------------------------------------------------------------------------------
// Get a list of all supported file extensions
const aiImporterDesc* SMDImporter::GetInfo () const {
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void SMDImporter::SetupProperties(const Importer* pImp) {
    // The
    // AI_CONFIG_IMPORT_SMD_KEYFRAME option overrides the
    // AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
    configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_SMD_KEYFRAME,-1);
    if(static_cast<unsigned int>(-1) == configFrameID)  {
        configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME,0);
    }

    bLoadAnimationList = pImp->GetPropertyBool(AI_CONFIG_IMPORT_SMD_LOAD_ANIMATION_LIST, true);
    noSkeletonMesh = pImp->GetPropertyBool(AI_CONFIG_IMPORT_NO_SKELETON_MESHES, false);
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void SMDImporter::InternReadFile( const std::string& pFile, aiScene* scene, IOSystem* pIOHandler) {
    this->pScene = scene;
    ReadSmd(pFile, pIOHandler);

    // If there are no triangles it seems to be an animation SMD,
    // containing only the animation skeleton.
    if (asTriangles.empty()) {
        if (asBones.empty()) {
            throw DeadlyImportError("SMD: No triangles and no bones have "
                "been found in the file. This file seems to be invalid.");
        }

        // Set the flag in the scene structure which indicates
        // that there is nothing than an animation skeleton
        pScene->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
    }

    if (!asBones.empty()) {
        // Check whether all bones have been initialized
        for (const auto &asBone : asBones) {
            if (!asBone.mName.length()) {
                ASSIMP_LOG_WARN("SMD: Not all bones have been initialized");
                break;
            }
        }

        // now fix invalid time values and make sure the animation starts at frame 0
        FixTimeValues();
    }

    // build output nodes (bones are added as empty dummy nodes)
    CreateOutputNodes();

    if (!(pScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE)) {
        // create output meshes
        CreateOutputMeshes();

        // build an output material list
        CreateOutputMaterials();

        // use root node that renders all meshes
        pScene->mRootNode->mNumMeshes = pScene->mNumMeshes;
        pScene->mRootNode->mMeshes = new unsigned int[pScene->mNumMeshes];
        for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
            pScene->mRootNode->mMeshes[i] = i;
        }
    }

    // build the output animation
    CreateOutputAnimations(pFile, pIOHandler);

    if ((pScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE) && !noSkeletonMesh) {
        SkeletonMeshBuilder skeleton(pScene);
    }
}

// ------------------------------------------------------------------------------------------------
// Write an error message with line number to the log file
void SMDImporter::LogErrorNoThrow(const char* msg) {
    const size_t _BufferSize = 1024;
    char szTemp[_BufferSize];
    ai_snprintf(szTemp,_BufferSize,"Line %u: %s",iLineNumber,msg);
    DefaultLogger::get()->error(szTemp);
}

// ------------------------------------------------------------------------------------------------
// Write a warning with line number to the log file
void SMDImporter::LogWarning(const char* msg) {
    const size_t _BufferSize = 1024;
    char szTemp[_BufferSize];
    ai_assert(strlen(msg) < 1000);
    ai_snprintf(szTemp,_BufferSize,"Line %u: %s",iLineNumber,msg);
    ASSIMP_LOG_WARN(szTemp);
}

// ------------------------------------------------------------------------------------------------
// Fix invalid time values in the file
void SMDImporter::FixTimeValues() {
    double dDelta = (double)iSmallestFrame;
    double dMax = 0.0f;
    for (auto &asBone : asBones) {
        for (auto &asKey : asBone.sAnim.asKeys) {
            asKey.dTime -= dDelta;
            dMax = std::max(dMax, asKey.dTime);
        }
    }
    dLengthOfAnim = dMax;
}

// ------------------------------------------------------------------------------------------------
// create output meshes
void SMDImporter::CreateOutputMeshes() {
    if (aszTextures.empty()) {
        aszTextures.emplace_back();
    }

    // we need to sort all faces by their material index
    // in opposition to other loaders we can be sure that each
    // material is at least used once.
    pScene->mNumMeshes = (unsigned int) aszTextures.size();
    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];

    typedef std::vector<unsigned int> FaceList;
    std::unique_ptr<FaceList[]> aaiFaces(new FaceList[pScene->mNumMeshes]);

    // approximate the space that will be required
    unsigned int iNum = (unsigned int)asTriangles.size() / pScene->mNumMeshes;
    iNum += iNum >> 1;
    for (unsigned int i = 0; i < pScene->mNumMeshes;++i) {
        aaiFaces[i].reserve(iNum);
    }

    // collect all faces
    iNum = 0;
    for (const auto &asTriangle : asTriangles) {
        if (asTriangle.iTexture >= aszTextures.size()) {
            ASSIMP_LOG_INFO("[SMD/VTA] Material index overflow in face");
            aaiFaces[asTriangle.iTexture].push_back((unsigned int)aszTextures.size()-1);
        } else {
            aaiFaces[asTriangle.iTexture].push_back(iNum);
        }
        ++iNum;
    }

    // now create the output meshes
    for (unsigned int i = 0; i < pScene->mNumMeshes;++i) {
        aiMesh*& pcMesh = pScene->mMeshes[i] = new aiMesh();
        ai_assert(!aaiFaces[i].empty()); // should not be empty ...

        pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
        pcMesh->mNumVertices = (unsigned int)aaiFaces[i].size()*3;
        pcMesh->mNumFaces = (unsigned int)aaiFaces[i].size();
        pcMesh->mMaterialIndex = i;

        // storage for bones
        typedef std::pair<unsigned int,float> TempWeightListEntry;
        typedef std::vector< TempWeightListEntry > TempBoneWeightList;

        std::unique_ptr<TempBoneWeightList[]> aaiBones(new TempBoneWeightList[asBones.size()]());

        // try to reserve enough memory without wasting too much
        for (unsigned int iBone = 0; iBone < asBones.size();++iBone) {
            aaiBones[iBone].reserve(pcMesh->mNumVertices/asBones.size());
        }

        // allocate storage
        pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
        aiVector3D* pcNormals = pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
        aiVector3D* pcVerts = pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];

        aiVector3D* pcUVs = nullptr;
        if (bHasUVs) {
            pcUVs = pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
            pcMesh->mNumUVComponents[0] = 2;
        }

        iNum = 0;
        for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces;++iFace) {
            pcMesh->mFaces[iFace].mIndices = new unsigned int[3];
            pcMesh->mFaces[iFace].mNumIndices = 3;

            // fill the vertices
            unsigned int iSrcFace = aaiFaces[i][iFace];
            SMD::Face& face = asTriangles[iSrcFace];

            *pcVerts++ = face.avVertices[0].pos;
            *pcVerts++ = face.avVertices[1].pos;
            *pcVerts++ = face.avVertices[2].pos;

            // fill the normals
            *pcNormals++ = face.avVertices[0].nor;
            *pcNormals++ = face.avVertices[1].nor;
            *pcNormals++ = face.avVertices[2].nor;

            // fill the texture coordinates
            if (pcUVs) {
                *pcUVs++ = face.avVertices[0].uv;
                *pcUVs++ = face.avVertices[1].uv;
                *pcUVs++ = face.avVertices[2].uv;
            }

            for (unsigned int iVert = 0; iVert < 3;++iVert) {
                float fSum = 0.0f;
                for (unsigned int iBone = 0;iBone < face.avVertices[iVert].aiBoneLinks.size();++iBone)  {
                    TempWeightListEntry& pairval = face.avVertices[iVert].aiBoneLinks[iBone];

                    // FIX: The second check is here just to make sure we won't
                    // assign more than one weight to a single vertex index
                    if (pairval.first >= asBones.size() || pairval.first == face.avVertices[iVert].iParentNode) {
                        ASSIMP_LOG_ERROR("[SMD/VTA] Bone index overflow. "
                            "The bone index will be ignored, the weight will be assigned "
                            "to the vertex' parent node");
                        continue;
                    }
                    aaiBones[pairval.first].emplace_back(iNum,pairval.second);
                    fSum += pairval.second;
                }
                // ******************************************************************
                // If the sum of all vertex weights is not 1.0 we must assign
                // the rest to the vertex' parent node. Well, at least the doc says
                // we should ...
                // FIX: We use 0.975 as limit, floating-point inaccuracies seem to
                // be very strong in some SMD exporters. Furthermore it is possible
                // that the parent of a vertex is 0xffffffff (if the corresponding
                // entry in the file was unreadable)
                // ******************************************************************
                if (fSum < 0.975f && face.avVertices[iVert].iParentNode != UINT_MAX) {
                    if (face.avVertices[iVert].iParentNode >= asBones.size()) {
                        ASSIMP_LOG_ERROR("[SMD/VTA] Bone index overflow. "
                            "The index of the vertex parent bone is invalid. "
                            "The remaining weights will be normalized to 1.0");

                        if (fSum) {
                            fSum = 1 / fSum;
                            for (auto &pairval : face.avVertices[iVert].aiBoneLinks) {
                                if (pairval.first >= asBones.size()) {
                                    continue;
                                }
                                aaiBones[pairval.first].back().second *= fSum;
                            }
                        }
                    } else {
                        aaiBones[face.avVertices[iVert].iParentNode].emplace_back(iNum,1.0f-fSum);
                    }
                }
                pcMesh->mFaces[iFace].mIndices[iVert] = iNum++;
            }
        }

        // now build all bones of the mesh
        iNum = 0;
        for (unsigned int iBone = 0; iBone < asBones.size();++iBone) {
            if (!aaiBones[iBone].empty())++iNum;
        }

        if (iNum) {
            pcMesh->mNumBones = iNum;
            pcMesh->mBones = new aiBone*[pcMesh->mNumBones];
            iNum = 0;
            for (unsigned int iBone = 0; iBone < asBones.size();++iBone) {
                if (aaiBones[iBone].empty()) {
                    continue;
                }
                aiBone*& bone = pcMesh->mBones[iNum] = new aiBone();

                bone->mNumWeights = (unsigned int)aaiBones[iBone].size();
                bone->mWeights = new aiVertexWeight[bone->mNumWeights];
                bone->mOffsetMatrix = asBones[iBone].mOffsetMatrix;
                bone->mName.Set( asBones[iBone].mName );

                asBones[iBone].bIsUsed = true;

                for (unsigned int iWeight = 0; iWeight < bone->mNumWeights;++iWeight) {
                    bone->mWeights[iWeight].mVertexId = aaiBones[iBone][iWeight].first;
                    bone->mWeights[iWeight].mWeight = aaiBones[iBone][iWeight].second;
                }
                ++iNum;
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
// add bone child nodes
void SMDImporter::AddBoneChildren(aiNode* pcNode, uint32_t iParent) {
    ai_assert( nullptr != pcNode );
    ai_assert( 0 == pcNode->mNumChildren );
    ai_assert( nullptr == pcNode->mChildren);

    // first count ...
    for (auto &bone : asBones) {
        if (bone.iParent == iParent) {
            ++pcNode->mNumChildren;
        }
    }

    // nothing to do
    if (pcNode->mNumChildren == 0)
        return;

    // now allocate the output array
    pcNode->mChildren = new aiNode *[pcNode->mNumChildren];

    // and fill all subnodes
    unsigned int qq( 0 );
    for (unsigned int i = 0; i < asBones.size();++i) {
        SMD::Bone& bone = asBones[i];
        if (bone.iParent != iParent) {
            continue;
        }

        aiNode* pc = pcNode->mChildren[qq++] = new aiNode();
        pc->mName.Set(bone.mName);

        // store the local transformation matrix of the bind pose
        if (bone.sAnim.asKeys.size()) {
            pc->mTransformation = bone.sAnim.asKeys[0].matrix;
        }

        if (bone.iParent == static_cast<uint32_t>(-1)) {
            bone.mOffsetMatrix = pc->mTransformation;
        } else {
            bone.mOffsetMatrix = asBones[bone.iParent].mOffsetMatrix * pc->mTransformation;
        }

        pc->mParent = pcNode;

        // add children to this node, too
        AddBoneChildren(pc,i);
    }
}

// ------------------------------------------------------------------------------------------------
// create output nodes
void SMDImporter::CreateOutputNodes() {
    pScene->mRootNode = new aiNode();

    // now add all bones as dummy sub nodes to the graph
    AddBoneChildren(pScene->mRootNode,(uint32_t)-1);
    for (auto &bone : asBones) {
        bone.mOffsetMatrix.Inverse();
    }

    // if we have only one bone we can even remove the root node
    if (pScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE && 1 == pScene->mRootNode->mNumChildren) {
        aiNode* pcOldRoot = pScene->mRootNode;
        pScene->mRootNode = pcOldRoot->mChildren[0];
        pcOldRoot->mChildren[0] = nullptr;
        delete pcOldRoot;

        pScene->mRootNode->mParent = nullptr;
    } else {
        static constexpr char rootName[11] = "<SMD_root>";
        pScene->mRootNode->mName.length = 10;
        ::strncpy(pScene->mRootNode->mName.data, rootName, pScene->mRootNode->mName.length);
    }
}

// ------------------------------------------------------------------------------------------------
// create output animations
void SMDImporter::CreateOutputAnimations(const std::string &pFile, IOSystem* pIOHandler) {
    std::vector<std::tuple<std::string, std::string>> animFileList;

    if (bLoadAnimationList) {
        GetAnimationFileList(pFile, pIOHandler, animFileList);
    }
    int animCount = static_cast<int>( animFileList.size() + 1u );
    pScene->mNumAnimations = 1;
    pScene->mAnimations = new aiAnimation*[animCount];
    memset(pScene->mAnimations, 0, sizeof(aiAnimation*)*animCount);
    CreateOutputAnimation(0, "");

    for (auto &animFile : animFileList) {
        ReadSmd(std::get<1>(animFile), pIOHandler);
        if (asBones.empty()) {
            continue;
        }

        FixTimeValues();
        CreateOutputAnimation(pScene->mNumAnimations++, std::get<0>(animFile));
    }
}

void SMDImporter::CreateOutputAnimation(int index, const std::string &name) {
    aiAnimation*& anim = pScene->mAnimations[index] = new aiAnimation();

    if (name.length()) {
        anim->mName.Set(name.c_str());
    }
    anim->mDuration = dLengthOfAnim;
    anim->mNumChannels = static_cast<unsigned int>( asBones.size() );
    anim->mTicksPerSecond = 25.0; // FIXME: is this correct?

    aiNodeAnim** pp = anim->mChannels = new aiNodeAnim*[anim->mNumChannels];

    // now build valid keys
    unsigned int a = 0;
    for (const auto &asBone : asBones) {
        aiNodeAnim* p = pp[a] = new aiNodeAnim();

        // copy the name of the bone
        p->mNodeName.Set(asBone.mName);

        p->mNumRotationKeys = (unsigned int)asBone.sAnim.asKeys.size();
        if (p->mNumRotationKeys){
            p->mNumPositionKeys = p->mNumRotationKeys;
            aiVectorKey* pVecKeys = p->mPositionKeys = new aiVectorKey[p->mNumRotationKeys];
            aiQuatKey* pRotKeys = p->mRotationKeys = new aiQuatKey[p->mNumRotationKeys];

            for (const auto &asKey : asBone.sAnim.asKeys) {
                pRotKeys->mTime = pVecKeys->mTime = asKey.dTime;

                // compute the rotation quaternion from the euler angles
                // aiQuaternion: The order of the parameters is yzx?
                pRotKeys->mValue = aiQuaternion(asKey.vRot.y, asKey.vRot.z, asKey.vRot.x);
                pVecKeys->mValue = asKey.vPos;

                ++pVecKeys; ++pRotKeys;
            }
        }
        ++a;

        // there are no scaling keys ...
    }
}

void SMDImporter::GetAnimationFileList(const std::string &pFile, IOSystem* pIOHandler, std::vector<std::tuple<std::string, std::string>>& outList) {
    auto base = DefaultIOSystem::absolutePath(pFile);
    auto name = DefaultIOSystem::completeBaseName(pFile);
    auto path = base + "/" + name + "_animation.txt";

    std::unique_ptr<IOStream> file(pIOHandler->Open(path.c_str(), "rb"));
    if (file == nullptr) {
        return;
    }

    // Allocate storage and copy the contents of the file to a memory buffer
    std::vector<char> buf;
    size_t fileSize = file->FileSize();
    buf.resize(fileSize + 1);
    TextFileToBuffer(file.get(), buf);

    /*
        *_animation.txt format:
        name path
        idle idle.smd
        jump anim/jump.smd
        walk.smd
        ...
    */
    std::string animName, animPath;
    char *tok1, *tok2;
    char *context1, *context2;

    tok1 = strtok_s(&buf[0], "\r\n", &context1);
    while (tok1 != nullptr) {
        tok2 = strtok_s(tok1, " \t", &context2);
        if (tok2) {
            char *p = tok2;
            tok2 = strtok_s(nullptr, " \t", &context2);
            if (tok2) {
                animPath = tok2;
                animName = p;
            } else  {
                // No name
                animPath = p;
                animName = DefaultIOSystem::completeBaseName(animPath);
            }
            outList.emplace_back(animName, base + "/" + animPath);
        }
        tok1 = strtok_s(nullptr, "\r\n", &context1);
    }
}

// ------------------------------------------------------------------------------------------------
// create output materials
void SMDImporter::CreateOutputMaterials() {
    ai_assert( nullptr != pScene );

    pScene->mNumMaterials = (unsigned int)aszTextures.size();
    pScene->mMaterials = new aiMaterial*[std::max(1u, pScene->mNumMaterials)];

    for (unsigned int iMat = 0; iMat < pScene->mNumMaterials; ++iMat) {
        aiMaterial* pcMat = new aiMaterial();
        ai_assert( nullptr != pcMat );
        pScene->mMaterials[iMat] = pcMat;

        aiString szName;
        szName.length = static_cast<ai_uint32>(ai_snprintf(szName.data, AI_MAXLEN, "Texture_%u", iMat));
        pcMat->AddProperty(&szName,AI_MATKEY_NAME);

        if (aszTextures[iMat].length())
        {
            ::strncpy(szName.data, aszTextures[iMat].c_str(), AI_MAXLEN - 1);
            szName.length = static_cast<ai_uint32>( aszTextures[iMat].length() );
            pcMat->AddProperty(&szName,AI_MATKEY_TEXTURE_DIFFUSE(0));
        }
    }

    // create a default material if necessary
    if (0 == pScene->mNumMaterials) {
        pScene->mNumMaterials = 1;

        aiMaterial* pcHelper = new aiMaterial();
        pScene->mMaterials[0] = pcHelper;

        int iMode = static_cast<int>(aiShadingMode_Gouraud);
        pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

        aiColor3D clr;
        clr.b = clr.g = clr.r = 0.7f;
        pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
        pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

        clr.b = clr.g = clr.r = 0.05f;
        pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

        aiString szName;
        szName.Set(AI_DEFAULT_MATERIAL_NAME);
        pcHelper->AddProperty(&szName,AI_MATKEY_NAME);
    }
}

// ------------------------------------------------------------------------------------------------
// Parse the file
void SMDImporter::ParseFile() {
    const char* szCurrent = &mBuffer[0];

    // read line per line ...
    for ( ;; ) {
        if(!SkipSpacesAndLineEnd(szCurrent,&szCurrent, mEnd)) {
            break;
        }

        // "version <n> \n", <n> should be 1 for hl and hl2 SMD files
        if (TokenMatch(szCurrent,"version",7)) {
            if(!SkipSpaces(szCurrent,&szCurrent, mEnd)) break;
            if (1 != strtoul10(szCurrent,&szCurrent)) {
                ASSIMP_LOG_WARN("SMD.version is not 1. This "
                    "file format is not known. Continuing happily ...");
            }
            continue;
        }
        // "nodes\n" - Starts the node section
        if (TokenMatch(szCurrent,"nodes",5)) {
            ParseNodesSection(szCurrent, &szCurrent, mEnd);
            continue;
        }
        // "triangles\n" - Starts the triangle section
        if (TokenMatch(szCurrent,"triangles",9)) {
            ParseTrianglesSection(szCurrent, &szCurrent, mEnd);
            continue;
        }
        // "vertexanimation\n" - Starts the vertex animation section
        if (TokenMatch(szCurrent,"vertexanimation",15)) {
            bHasUVs = false;
            ParseVASection(szCurrent, &szCurrent, mEnd);
            continue;
        }
        // "skeleton\n" - Starts the skeleton section
        if (TokenMatch(szCurrent,"skeleton",8)) {
            ParseSkeletonSection(szCurrent, &szCurrent, mEnd);
            continue;
        }
        SkipLine(szCurrent, &szCurrent, mEnd);
    }
}

void SMDImporter::ReadSmd(const std::string &pFile, IOSystem* pIOHandler) {
    std::unique_ptr<IOStream> file(pIOHandler->Open(pFile, "rb"));

    // Check whether we can read from the file
    if (file == nullptr) {
        throw DeadlyImportError("Failed to open SMD/VTA file ", pFile, ".");
    }

    iFileSize = (unsigned int)file->FileSize();

    // Allocate storage and copy the contents of the file to a memory buffer
    mBuffer.resize(iFileSize + 1);
    TextFileToBuffer(file.get(), mBuffer);
    mEnd = &mBuffer[mBuffer.size() - 1] + 1;

    iSmallestFrame = INT_MAX;
    bHasUVs = true;
    iLineNumber = 1;

    // Reserve enough space for ... hm ... 10 textures
    aszTextures.reserve(10);

    // Reserve enough space for ... hm ... 1000 triangles
    asTriangles.reserve(1000);

    // Reserve enough space for ... hm ... 20 bones
    asBones.reserve(20);

    aszTextures.clear();
    asTriangles.clear();
    asBones.clear();

    // parse the file ...
    ParseFile();
}

// ------------------------------------------------------------------------------------------------
unsigned int SMDImporter::GetTextureIndex(const std::string& filename) {
    unsigned int iIndex = 0;
    for (std::vector<std::string>::const_iterator
            i =  aszTextures.begin();
            i != aszTextures.end();++i,++iIndex) {
        // case-insensitive ... it's a path
        if (0 == ASSIMP_stricmp ( filename.c_str(),(*i).c_str())) {
            return iIndex;
        }
    }
    iIndex = (unsigned int)aszTextures.size();
    aszTextures.push_back(filename);
    return iIndex;
}

// ------------------------------------------------------------------------------------------------
// Parse the nodes section of the file
void SMDImporter::ParseNodesSection(const char* szCurrent, const char** szCurrentOut, const char *end) {
    for ( ;; ) {
        // "end\n" - Ends the nodes section
        if (0 == ASSIMP_strincmp(szCurrent, "end", 3) && IsSpaceOrNewLine(*(szCurrent+3))) {
            szCurrent += 4;
            break;
        }
        ParseNodeInfo(szCurrent,&szCurrent, end);
    }
    SkipSpacesAndLineEnd(szCurrent, &szCurrent, end);
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
// Parse the triangles section of the file
void SMDImporter::ParseTrianglesSection(const char *szCurrent, const char **szCurrentOut, const char *end) {
    // Parse a triangle, parse another triangle, parse the next triangle ...
    // and so on until we reach a token that looks quite similar to "end"
    for ( ;; ) {
        if(!SkipSpacesAndLineEnd(szCurrent,&szCurrent, end)) {
            break;
        }

        // "end\n" - Ends the triangles section
        if (TokenMatch(szCurrent,"end",3)) {
            break;
        }
        ParseTriangle(szCurrent,&szCurrent, end);
    }
    SkipSpacesAndLineEnd(szCurrent,&szCurrent, end);
    *szCurrentOut = szCurrent;
}
// ------------------------------------------------------------------------------------------------
// Parse the vertex animation section of the file
void SMDImporter::ParseVASection(const char *szCurrent, const char **szCurrentOut, const char *end) {
    unsigned int iCurIndex = 0;
    for ( ;; ) {
        if (!SkipSpacesAndLineEnd(szCurrent,&szCurrent, end)) {
            break;
        }

        // "end\n" - Ends the "vertexanimation" section
        if (TokenMatch(szCurrent,"end",3)) {
            break;
        }

        // "time <n>\n"
        if (TokenMatch(szCurrent,"time",4)) {
            // NOTE: The doc says that time values COULD be negative ...
            // NOTE2: this is the shape key -> valve docs
            int iTime = 0;
            if (!ParseSignedInt(szCurrent, &szCurrent, end, iTime) || configFrameID != (unsigned int)iTime) {
                break;
            }
            SkipLine(szCurrent,&szCurrent, end);
        } else {
            if(0 == iCurIndex) {
                asTriangles.emplace_back();
            }
            if (++iCurIndex == 3) {
                iCurIndex = 0;
            }
            ParseVertex(szCurrent,&szCurrent, end, asTriangles.back().avVertices[iCurIndex],true);
        }
    }

    if (iCurIndex != 2 && !asTriangles.empty()) {
        // we want to no degenerates, so throw this triangle away
        asTriangles.pop_back();
    }

    SkipSpacesAndLineEnd(szCurrent,&szCurrent, end);
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
// Parse the skeleton section of the file
void SMDImporter::ParseSkeletonSection(const char *szCurrent, const char **szCurrentOut, const char *end) {
    int iTime = 0;
    for ( ;; ) {
        if (!SkipSpacesAndLineEnd(szCurrent,&szCurrent, end)) {
            break;
        }

        // "end\n" - Ends the skeleton section
        if (TokenMatch(szCurrent,"end",3)) {
            break;
        } else if (TokenMatch(szCurrent,"time",4)) {
            // "time <n>\n" - Specifies the current animation frame
            if (!ParseSignedInt(szCurrent, &szCurrent, end, iTime)) {
                break;
            }

            iSmallestFrame = std::min(iSmallestFrame,iTime);
            SkipLine(szCurrent, &szCurrent, end);
        } else {
            ParseSkeletonElement(szCurrent, &szCurrent, end, iTime);
        }
    }
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
#define SMDI_PARSE_RETURN { \
    SkipLine(szCurrent,&szCurrent, end); \
    *szCurrentOut = szCurrent; \
    return; \
}
// ------------------------------------------------------------------------------------------------
// Parse a node line
void SMDImporter::ParseNodeInfo(const char *szCurrent, const char **szCurrentOut, const char *end) {
    unsigned int iBone  = 0;
    SkipSpacesAndLineEnd(szCurrent, &szCurrent, end);
    if ( !ParseUnsignedInt(szCurrent, &szCurrent, end, iBone) || !SkipSpaces(szCurrent,&szCurrent, end)) {
        throw DeadlyImportError("Unexpected EOF/EOL while parsing bone index");
    }
    if (iBone == UINT_MAX) {
        LogErrorNoThrow("Invalid bone number while parsing bone index");
        SMDI_PARSE_RETURN;
    }
    // add our bone to the list
    if (iBone >= asBones.size()) {
        asBones.resize(iBone+1);
    }
    SMD::Bone& bone = asBones[iBone];

    bool bQuota = true;
    if ('\"' != *szCurrent) {
        LogWarning("Bone name is expected to be enclosed in "
            "double quotation marks. ");
        bQuota = false;
    } else {
        ++szCurrent;
    }

    const char* szEnd = szCurrent;
    for ( ;; ) {
        if (bQuota && '\"' == *szEnd) {
            iBone = (unsigned int)(szEnd - szCurrent);
            ++szEnd;
            break;
        } else if (!bQuota && IsSpaceOrNewLine(*szEnd)) {
            iBone = (unsigned int)(szEnd - szCurrent);
            break;
        } else if (!(*szEnd)) {
            LogErrorNoThrow("Unexpected EOF/EOL while parsing bone name");
            SMDI_PARSE_RETURN;
        }
        ++szEnd;
    }
    bone.mName = std::string(szCurrent,iBone);
    szCurrent = szEnd;

    // the only negative bone parent index that could occur is -1 AFAIK
    if(!ParseSignedInt(szCurrent, &szCurrent, end, (int&)bone.iParent))  {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone parent index. Assuming -1");
        SMDI_PARSE_RETURN;
    }

    // go to the beginning of the next line
    SMDI_PARSE_RETURN;
}

// ------------------------------------------------------------------------------------------------
// Parse a skeleton element
void SMDImporter::ParseSkeletonElement(const char *szCurrent, const char **szCurrentOut, const char *end, int iTime) {
    aiVector3D vPos;
    aiVector3D vRot;

    unsigned int iBone  = 0;
    if (!ParseUnsignedInt(szCurrent, &szCurrent, end, iBone)) {
        ASSIMP_LOG_ERROR("Unexpected EOF/EOL while parsing bone index");
        SMDI_PARSE_RETURN;
    }
    if (iBone >= asBones.size()) {
        LogErrorNoThrow("Bone index in skeleton section is out of range");
        SMDI_PARSE_RETURN;
    }
    SMD::Bone& bone = asBones[iBone];

    bone.sAnim.asKeys.emplace_back();
    SMD::Bone::Animation::MatrixKey& key = bone.sAnim.asKeys.back();

    key.dTime = (double)iTime;
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vPos.x)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.pos.x");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vPos.y)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.pos.y");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vPos.z)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.pos.z");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vRot.x)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.rot.x");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vRot.y)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.rot.y");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vRot.z)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing bone.rot.z");
        SMDI_PARSE_RETURN;
    }
    // build the transformation matrix of the key
    key.matrix.FromEulerAnglesXYZ(vRot.x,vRot.y,vRot.z); {
        aiMatrix4x4 mTemp;
        mTemp.a4 = vPos.x;
        mTemp.b4 = vPos.y;
        mTemp.c4 = vPos.z;
        key.matrix = mTemp * key.matrix;
    }
    key.vPos = vPos;
    key.vRot = vRot;
    // go to the beginning of the next line
    SMDI_PARSE_RETURN;
}

// ------------------------------------------------------------------------------------------------
// Parse a triangle
void SMDImporter::ParseTriangle(const char *szCurrent, const char **szCurrentOut, const char *end) {
    asTriangles.emplace_back();
    SMD::Face& face = asTriangles.back();

    if(!SkipSpaces(szCurrent, &szCurrent, end)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing a triangle");
        return;
    }

    // read the texture file name
    const char* szLast = szCurrent;
    while (!IsSpaceOrNewLine(*++szCurrent));

    // ... and get the index that belongs to this file name
    face.iTexture = GetTextureIndex(std::string(szLast,(uintptr_t)szCurrent-(uintptr_t)szLast));

    SkipSpacesAndLineEnd(szCurrent, &szCurrent, end);

    // load three vertices
    for (auto &avVertex : face.avVertices) {
        ParseVertex(szCurrent, &szCurrent, end, avVertex);
    }
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
// Parse a float
bool SMDImporter::ParseFloat(const char *szCurrent, const char **szCurrentOut, const char *end, float &out) {
    if (!SkipSpaces(&szCurrent, end)) {
        return false;
    }

    *szCurrentOut = fast_atoreal_move(szCurrent,out);
    return true;
}

// ------------------------------------------------------------------------------------------------
// Parse an unsigned int
bool SMDImporter::ParseUnsignedInt(const char *szCurrent, const char **szCurrentOut, const char *end, unsigned int &out) {
    if(!SkipSpaces(&szCurrent, end)) {
        return false;
    }

    out = strtoul10(szCurrent,szCurrentOut);
    return true;
}

// ------------------------------------------------------------------------------------------------
// Parse a signed int
bool SMDImporter::ParseSignedInt(const char *szCurrent, const char **szCurrentOut, const char *end, int &out) {
    if(!SkipSpaces(&szCurrent, end)) {
        return false;
    }

    out = strtol10(szCurrent,szCurrentOut);
    return true;
}

// ------------------------------------------------------------------------------------------------
// Parse a vertex
void SMDImporter::ParseVertex(const char* szCurrent,
        const char **szCurrentOut, const char *end, SMD::Vertex &vertex,
        bool bVASection /*= false*/) {
    if (SkipSpaces(&szCurrent, end) && IsLineEnd(*szCurrent)) {
        SkipSpacesAndLineEnd(szCurrent,&szCurrent, end);
        return ParseVertex(szCurrent, szCurrentOut, end, vertex, bVASection);
    }
    if(!ParseSignedInt(szCurrent, &szCurrent, end, (int&)vertex.iParentNode)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.parent");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.pos.x)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.pos.x");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.pos.y)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.pos.y");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.pos.z)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.pos.z");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent,&szCurrent,end, (float&)vertex.nor.x)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.nor.x");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent,&szCurrent, end, (float&)vertex.nor.y)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.nor.y");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.nor.z)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.nor.z");
        SMDI_PARSE_RETURN;
    }

    if (bVASection) {
        SMDI_PARSE_RETURN;
    }

    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.uv.x)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.uv.x");
        SMDI_PARSE_RETURN;
    }
    if(!ParseFloat(szCurrent, &szCurrent, end, (float&)vertex.uv.y)) {
        LogErrorNoThrow("Unexpected EOF/EOL while parsing vertex.uv.y");
        SMDI_PARSE_RETURN;
    }

    // now read the number of bones affecting this vertex
    // all elements from now are fully optional, we don't need them
    unsigned int iSize = 0;
    if(!ParseUnsignedInt(szCurrent, &szCurrent, end, iSize)) {
        SMDI_PARSE_RETURN;
    }
    vertex.aiBoneLinks.resize(iSize,std::pair<unsigned int, float>(0,0.0f));

    for (auto &aiBoneLink : vertex.aiBoneLinks) {
        if(!ParseUnsignedInt(szCurrent, &szCurrent, end, aiBoneLink.first)) {
            SMDI_PARSE_RETURN;
        }
        if(!ParseFloat(szCurrent, &szCurrent, end, aiBoneLink.second)) {
            SMDI_PARSE_RETURN;
        }
    }

    // go to the beginning of the next line
    SMDI_PARSE_RETURN;
}

} // namespace Assimp

#endif // !! ASSIMP_BUILD_NO_SMD_IMPORTER
