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/** @file  UnrealLoader.cpp
 *  @brief Implementation of the UNREAL (*.3D) importer class
 *
 *  Sources:
 *    http://local.wasp.uwa.edu.au/~pbourke/dataformats/unreal/
 */


#ifndef ASSIMP_BUILD_NO_3D_IMPORTER

#include "UnrealLoader.h"
#include "StreamReader.h"
#include "ParsingUtils.h"
#include "fast_atof.h"
#include "ConvertToLHProcess.h"

#include <assimp/Importer.hpp>
#include <assimp/DefaultLogger.hpp>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/importerdesc.h>

#include <memory>

using namespace Assimp;

static const aiImporterDesc desc = {
    "Unreal Mesh Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportTextFlavour,
    0,
    0,
    0,
    0,
    "3d uc"
};


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
UnrealImporter::UnrealImporter()
:   configFrameID   (0)
,   configHandleFlags (true)
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
UnrealImporter::~UnrealImporter()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool UnrealImporter::CanRead( const std::string& pFile, IOSystem* /*pIOHandler*/, bool /*checkSig*/) const
{
    return  SimpleExtensionCheck(pFile,"3d","uc");
}

// ------------------------------------------------------------------------------------------------
// Build a string of all file extensions supported
const aiImporterDesc* UnrealImporter::GetInfo () const
{
    return &desc;
}

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

    // AI_CONFIG_IMPORT_UNREAL_HANDLE_FLAGS, default is true
    configHandleFlags = (0 != pImp->GetPropertyInteger(AI_CONFIG_IMPORT_UNREAL_HANDLE_FLAGS,1));
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void UnrealImporter::InternReadFile( const std::string& pFile,
    aiScene* pScene, IOSystem* pIOHandler)
{
    // For any of the 3 files being passed get the three correct paths
    // First of all, determine file extension
    std::string::size_type pos = pFile.find_last_of('.');
    std::string extension = GetExtension(pFile);

    std::string d_path,a_path,uc_path;
    if (extension == "3d")      {
        // jjjj_d.3d
        // jjjj_a.3d
        pos = pFile.find_last_of('_');
        if (std::string::npos == pos) {
            throw DeadlyImportError("UNREAL: Unexpected naming scheme");
        }
        extension = pFile.substr(0,pos);
    }
    else {
        extension = pFile.substr(0,pos);
    }

    // build proper paths
    d_path  = extension+"_d.3d";
    a_path  = extension+"_a.3d";
    uc_path = extension+".uc";

    DefaultLogger::get()->debug("UNREAL: data file is " + d_path);
    DefaultLogger::get()->debug("UNREAL: aniv file is " + a_path);
    DefaultLogger::get()->debug("UNREAL: uc file is "   + uc_path);

    // and open the files ... we can't live without them
    std::unique_ptr<IOStream> p(pIOHandler->Open(d_path));
    if (!p)
        throw DeadlyImportError("UNREAL: Unable to open _d file");
    StreamReaderLE d_reader(pIOHandler->Open(d_path));

    const uint16_t numTris = d_reader.GetI2();
    const uint16_t numVert = d_reader.GetI2();
    d_reader.IncPtr(44);
    if (!numTris || numVert < 3)
        throw DeadlyImportError("UNREAL: Invalid number of vertices/triangles");

    // maximum texture index
    unsigned int maxTexIdx = 0;

    // collect triangles
    std::vector<Unreal::Triangle> triangles(numTris);
    for (auto & tri : triangles) {
        for (unsigned int i = 0; i < 3;++i) {

            tri.mVertex[i] = d_reader.GetI2();
            if (tri.mVertex[i] >= numTris)  {
                DefaultLogger::get()->warn("UNREAL: vertex index out of range");
                tri.mVertex[i] = 0;
            }
        }
        tri.mType = d_reader.GetI1();

        // handle mesh flagss?
        if (configHandleFlags)
            tri.mType = Unreal::MF_NORMAL_OS;
        else {
            // ignore MOD and MASKED for the moment, treat them as two-sided
            if (tri.mType == Unreal::MF_NORMAL_MOD_TS || tri.mType == Unreal::MF_NORMAL_MASKED_TS)
                tri.mType = Unreal::MF_NORMAL_TS;
        }
        d_reader.IncPtr(1);

        for (unsigned int i = 0; i < 3;++i)
            for (unsigned int i2 = 0; i2 < 2;++i2)
                tri.mTex[i][i2] = d_reader.GetI1();

        tri.mTextureNum = d_reader.GetI1();
        maxTexIdx = std::max(maxTexIdx,(unsigned int)tri.mTextureNum);
        d_reader.IncPtr(1);
    }

    p.reset(pIOHandler->Open(a_path));
    if (!p)
        throw DeadlyImportError("UNREAL: Unable to open _a file");
    StreamReaderLE a_reader(pIOHandler->Open(a_path));

    // read number of frames
    const uint32_t numFrames = a_reader.GetI2();
    if (configFrameID >= numFrames)
        throw DeadlyImportError("UNREAL: The requested frame does not exist");

    uint32_t st = a_reader.GetI2();
    if (st != numVert*4)
        throw DeadlyImportError("UNREAL: Unexpected aniv file length");

    // skip to our frame
    a_reader.IncPtr(configFrameID *numVert*4);

    // collect vertices
    std::vector<aiVector3D> vertices(numVert);
    for (auto &vertex : vertices)    {
        int32_t val = a_reader.GetI4();
        Unreal::DecompressVertex(vertex ,val);
    }

    // list of textures.
    std::vector< std::pair<unsigned int, std::string> > textures;

    // allocate the output scene
    aiNode* nd = pScene->mRootNode = new aiNode();
    nd->mName.Set("<UnrealRoot>");

    // we can live without the uc file if necessary
    std::unique_ptr<IOStream> pb (pIOHandler->Open(uc_path));
    if (pb.get())   {

        std::vector<char> _data;
        TextFileToBuffer(pb.get(),_data);
        const char* data = &_data[0];

        std::vector< std::pair< std::string,std::string > > tempTextures;

        // do a quick search in the UC file for some known, usually texture-related, tags
        for (;*data;++data) {
            if (TokenMatchI(data,"#exec",5))    {
                SkipSpacesAndLineEnd(&data);

                // #exec TEXTURE IMPORT [...] NAME=jjjjj [...] FILE=jjjj.pcx [...]
                if (TokenMatchI(data,"TEXTURE",7))  {
                    SkipSpacesAndLineEnd(&data);

                    if (TokenMatchI(data,"IMPORT",6))   {
                        tempTextures.push_back(std::pair< std::string,std::string >());
                        std::pair< std::string,std::string >& me = tempTextures.back();
                        for (;!IsLineEnd(*data);++data) {
                            if (!::ASSIMP_strincmp(data,"NAME=",5)) {
                                const char *d = data+=5;
                                for (;!IsSpaceOrNewLine(*data);++data);
                                me.first = std::string(d,(size_t)(data-d));
                            }
                            else if (!::ASSIMP_strincmp(data,"FILE=",5))    {
                                const char *d = data+=5;
                                for (;!IsSpaceOrNewLine(*data);++data);
                                me.second = std::string(d,(size_t)(data-d));
                            }
                        }
                        if (!me.first.length() || !me.second.length())
                            tempTextures.pop_back();
                    }
                }
                // #exec MESHMAP SETTEXTURE MESHMAP=box NUM=1 TEXTURE=Jtex1
                // #exec MESHMAP SCALE MESHMAP=box X=0.1 Y=0.1 Z=0.2
                else if (TokenMatchI(data,"MESHMAP",7)) {
                    SkipSpacesAndLineEnd(&data);

                    if (TokenMatchI(data,"SETTEXTURE",10)) {

                        textures.push_back(std::pair<unsigned int, std::string>());
                        std::pair<unsigned int, std::string>& me = textures.back();

                        for (;!IsLineEnd(*data);++data) {
                            if (!::ASSIMP_strincmp(data,"NUM=",4))  {
                                data += 4;
                                me.first = strtoul10(data,&data);
                            }
                            else if (!::ASSIMP_strincmp(data,"TEXTURE=",8)) {
                                data += 8;
                                const char *d = data;
                                for (;!IsSpaceOrNewLine(*data);++data);
                                me.second = std::string(d,(size_t)(data-d));

                                // try to find matching path names, doesn't care if we don't find them
                                for (std::vector< std::pair< std::string,std::string > >::const_iterator it = tempTextures.begin();
                                     it != tempTextures.end(); ++it)    {
                                    if ((*it).first == me.second)   {
                                        me.second = (*it).second;
                                        break;
                                    }
                                }
                            }
                        }
                    }
                    else if (TokenMatchI(data,"SCALE",5)) {

                        for (;!IsLineEnd(*data);++data) {
                            if (data[0] == 'X' && data[1] == '=')   {
                                data = fast_atoreal_move<float>(data+2,(float&)nd->mTransformation.a1);
                            }
                            else if (data[0] == 'Y' && data[1] == '=')  {
                                data = fast_atoreal_move<float>(data+2,(float&)nd->mTransformation.b2);
                            }
                            else if (data[0] == 'Z' && data[1] == '=')  {
                                data = fast_atoreal_move<float>(data+2,(float&)nd->mTransformation.c3);
                            }
                        }
                    }
                }
            }
        }
    }
    else    {
        DefaultLogger::get()->error("Unable to open .uc file");
    }

    std::vector<Unreal::TempMat> materials;
    materials.reserve(textures.size()*2+5);

    // find out how many output meshes and materials we'll have and build material indices
	for (Unreal::Triangle &tri : triangles) {
        Unreal::TempMat mat(tri);
        std::vector<Unreal::TempMat>::iterator nt = std::find(materials.begin(),materials.end(),mat);
        if (nt == materials.end()) {
            // add material
            tri.matIndex = static_cast<unsigned int>(materials.size());
            mat.numFaces = 1;
            materials.push_back(mat);

            ++pScene->mNumMeshes;
        }
        else {
            tri.matIndex = static_cast<unsigned int>(nt-materials.begin());
            ++nt->numFaces;
        }
    }

    if (!pScene->mNumMeshes) {
        throw DeadlyImportError("UNREAL: Unable to find valid mesh data");
    }

    // allocate meshes and bind them to the node graph
    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
    pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials = pScene->mNumMeshes];

    nd->mNumMeshes  = pScene->mNumMeshes;
    nd->mMeshes = new unsigned int[nd->mNumMeshes];
    for (unsigned int i = 0; i < pScene->mNumMeshes;++i) {
        aiMesh* m = pScene->mMeshes[i] =  new aiMesh();
        m->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;

        const unsigned int num = materials[i].numFaces;
        m->mFaces            = new aiFace     [num];
        m->mVertices         = new aiVector3D [num*3];
        m->mTextureCoords[0] = new aiVector3D [num*3];

        nd->mMeshes[i] = i;

        // create materials, too
        aiMaterial* mat = new aiMaterial();
        pScene->mMaterials[i] = mat;

        // all white by default - texture rulez
        aiColor3D color(1.f,1.f,1.f);

        aiString s;
        ::ai_snprintf( s.data, MAXLEN, "mat%u_tx%u_",i,materials[i].tex );

        // set the two-sided flag
        if (materials[i].type == Unreal::MF_NORMAL_TS) {
            const int twosided = 1;
            mat->AddProperty(&twosided,1,AI_MATKEY_TWOSIDED);
            ::strcat(s.data,"ts_");
        }
        else ::strcat(s.data,"os_");

        // make TRANS faces 90% opaque that RemRedundantMaterials won't catch us
        if (materials[i].type == Unreal::MF_NORMAL_TRANS_TS)    {
            const float opac = 0.9f;
            mat->AddProperty(&opac,1,AI_MATKEY_OPACITY);
            ::strcat(s.data,"tran_");
        }
        else ::strcat(s.data,"opaq_");

        // a special name for the weapon attachment point
        if (materials[i].type == Unreal::MF_WEAPON_PLACEHOLDER) {
            s.length = ::ai_snprintf( s.data, MAXLEN, "$WeaponTag$" );
            color = aiColor3D(0.f,0.f,0.f);
        }

        // set color and name
        mat->AddProperty(&color,1,AI_MATKEY_COLOR_DIFFUSE);
        s.length = ::strlen(s.data);
        mat->AddProperty(&s,AI_MATKEY_NAME);

        // set texture, if any
        const unsigned int tex = materials[i].tex;
        for (std::vector< std::pair< unsigned int, std::string > >::const_iterator it = textures.begin();it != textures.end();++it) {
            if ((*it).first == tex) {
                s.Set((*it).second);
                mat->AddProperty(&s,AI_MATKEY_TEXTURE_DIFFUSE(0));
                break;
            }
        }
    }

    // fill them.
    for (const Unreal::Triangle &tri : triangles) {
        Unreal::TempMat mat(tri);
        std::vector<Unreal::TempMat>::iterator nt = std::find(materials.begin(),materials.end(),mat);

        aiMesh* mesh = pScene->mMeshes[nt-materials.begin()];
        aiFace& f    = mesh->mFaces[mesh->mNumFaces++];
        f.mIndices   = new unsigned int[f.mNumIndices = 3];

        for (unsigned int i = 0; i < 3;++i,mesh->mNumVertices++) {
            f.mIndices[i] = mesh->mNumVertices;

            mesh->mVertices[mesh->mNumVertices] = vertices[ tri.mVertex[i] ];
            mesh->mTextureCoords[0][mesh->mNumVertices] = aiVector3D( tri.mTex[i][0] / 255.f, 1.f - tri.mTex[i][1] / 255.f, 0.f);
        }
    }

    // convert to RH
    MakeLeftHandedProcess hero;
    hero.Execute(pScene);

    FlipWindingOrderProcess flipper;
    flipper.Execute(pScene);
}

#endif // !! ASSIMP_BUILD_NO_3D_IMPORTER