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Open Asset Import Library (assimp)
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/** @file  OFFLoader.cpp
 *  @brief Implementation of the OFF importer class
 */


#ifndef ASSIMP_BUILD_NO_OFF_IMPORTER

// internal headers
#include "OFFLoader.h"
#include "ParsingUtils.h"
#include "fast_atof.h"
#include <memory>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/importerdesc.h>

using namespace Assimp;

static const aiImporterDesc desc = {
    "OFF Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    0,
    0,
    "off"
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
OFFImporter::OFFImporter()
{}

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

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool OFFImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
    const std::string extension = GetExtension(pFile);

    if (extension == "off")
        return true;
    else if (!extension.length() || checkSig)
    {
        if (!pIOHandler)return true;
        const char* tokens[] = {"off"};
        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc* OFFImporter::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void OFFImporter::InternReadFile( const std::string& pFile,
    aiScene* pScene, IOSystem* pIOHandler)
{
    std::unique_ptr<IOStream> file( pIOHandler->Open( pFile, "rb"));

    // Check whether we can read from the file
    if( file.get() == NULL) {
        throw DeadlyImportError( "Failed to open OFF file " + pFile + ".");
    }

    // allocate storage and copy the contents of the file to a memory buffer
    std::vector<char> mBuffer2;
    TextFileToBuffer(file.get(),mBuffer2);
    const char* buffer = &mBuffer2[0];

    char line[4096];
    GetNextLine(buffer,line);
    if ('O' == line[0]) {
        GetNextLine(buffer,line); // skip the 'OFF' line
    }

    const char* sz = line; SkipSpaces(&sz);
    const unsigned int numVertices = strtoul10(sz,&sz);SkipSpaces(&sz);
    const unsigned int numFaces = strtoul10(sz,&sz);

    if (!numVertices) {
        throw DeadlyImportError("OFF: There are no valid vertices");
    }
    if (!numFaces) {
        throw DeadlyImportError("OFF: There are no valid faces");
    }

    pScene->mNumMeshes = 1;
    pScene->mMeshes = new aiMesh*[ pScene->mNumMeshes ];

    aiMesh* mesh = new aiMesh();
    pScene->mMeshes[0] = mesh;

    mesh->mNumFaces = numFaces;
    aiFace* faces = new aiFace [mesh->mNumFaces];
    mesh->mFaces = faces;

    std::vector<aiVector3D> tempPositions(numVertices);

    // now read all vertex lines
    for (unsigned int i = 0; i< numVertices;++i)
    {
        if(!GetNextLine(buffer,line))
        {
            DefaultLogger::get()->error("OFF: The number of verts in the header is incorrect");
            break;
        }
        aiVector3D& v = tempPositions[i];

        sz = line; SkipSpaces(&sz);
        sz = fast_atoreal_move<ai_real>(sz,(ai_real&)v.x); SkipSpaces(&sz);
        sz = fast_atoreal_move<ai_real>(sz,(ai_real&)v.y); SkipSpaces(&sz);
        fast_atoreal_move<ai_real>(sz,(ai_real&)v.z);
    }


    // First find out how many vertices we'll need
    const char* old = buffer;
    for (unsigned int i = 0; i< mesh->mNumFaces;++i)
    {
        if(!GetNextLine(buffer,line))
        {
            DefaultLogger::get()->error("OFF: The number of faces in the header is incorrect");
            break;
        }
        sz = line;SkipSpaces(&sz);
        faces->mNumIndices = strtoul10(sz,&sz);
        if(!(faces->mNumIndices) || faces->mNumIndices > 9)
        {
            DefaultLogger::get()->error("OFF: Faces with zero indices aren't allowed");
            --mesh->mNumFaces;
            continue;
        }
        mesh->mNumVertices += faces->mNumIndices;
        ++faces;
    }

    if (!mesh->mNumVertices)
        throw DeadlyImportError("OFF: There are no valid faces");

    // allocate storage for the output vertices
    std::vector<aiVector3D> verts;
    verts.reserve(mesh->mNumVertices);

    // second: now parse all face indices
    buffer = old;
    faces = mesh->mFaces;
    for (unsigned int i = 0, p = 0; i< mesh->mNumFaces;)
    {
        if(!GetNextLine(buffer,line))break;

        unsigned int idx;
        sz = line;SkipSpaces(&sz);
        idx = strtoul10(sz,&sz);
        if(!(idx) || idx > 9)
            continue;

        faces->mIndices = new unsigned int [faces->mNumIndices];
        for (unsigned int m = 0; m < faces->mNumIndices;++m)
        {
            SkipSpaces(&sz);
            idx = strtoul10(sz,&sz);
            if ((idx) >= numVertices)
            {
                DefaultLogger::get()->error("OFF: Vertex index is out of range");
                idx = numVertices-1;
            }
            faces->mIndices[m] = p++;
            verts.push_back(tempPositions[idx]);
        }
        ++i;
        ++faces;
    }

    if (mesh->mNumVertices != verts.size()) {
        throw DeadlyImportError("OFF: Vertex count mismatch");
    }
    mesh->mVertices = new aiVector3D[verts.size()];
    memcpy(mesh->mVertices, &verts[0], verts.size() * sizeof(aiVector3D));
    // generate the output node graph
    pScene->mRootNode = new aiNode();
    pScene->mRootNode->mName.Set("<OFFRoot>");
    pScene->mRootNode->mNumMeshes = 1;
    pScene->mRootNode->mMeshes = new unsigned int [pScene->mRootNode->mNumMeshes];
    pScene->mRootNode->mMeshes[0] = 0;

    // generate a default material
    pScene->mNumMaterials = 1;
    pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials];
    aiMaterial* pcMat = new aiMaterial();

    aiColor4D clr( ai_real( 0.6 ), ai_real( 0.6 ), ai_real( 0.6 ), ai_real( 1.0 ) );
    pcMat->AddProperty(&clr,1,AI_MATKEY_COLOR_DIFFUSE);
    pScene->mMaterials[0] = pcMat;

    const int twosided =1;
    pcMat->AddProperty(&twosided,1,AI_MATKEY_TWOSIDED);
}

#endif // !! ASSIMP_BUILD_NO_OFF_IMPORTER
