OpenGL

开发平台：
Windows_Unix

3dsloader.cpp：源码内容
							#include <iostream.h>
#include <fstream>
#include "3dsloader.h"
CLoader3DS::CLoader3DS()
{
    m_pCurrentMesh = NULL;
    m_pCurrentObject = NULL;
    m_pCurrentMaterial = NULL;
    tm = NULL;
}
CLoader3DS::~CLoader3DS()
{
}
bool CLoader3DS::Load( std::string filename, CObject* pObj )
{
    //ifstream    file;
    FILE*       file;
    bool        doneloading = false;
    int         filelength;
    char*       memfile;        // file loaded into memory
    tm = Texture::GetInstance();
    m_pCurrentObject = pObj;
    file = fopen( filename.c_str(), "rb" );
    if (file == NULL)
        return false;
    fseek( file, 0, SEEK_END );
    filelength = ftell( file );
    memfile = new char[ filelength ];
    fseek( file, 0, SEEK_SET );
    fread( memfile, filelength, 1, file );
    // parse it
    EatChunk(memfile);
    delete memfile;
    fclose( file );
    return true;
}
// EatChunk
//
//  This function recursively handles chunks
// in a .3ds file.  When the function exits,
// the return value (i) should be the length
// of the current chunk.  Right now we only
// create one model (the first one listed in
// the file) and read in verts and polys only.
// To grab other info from the file, create
// a new case label in the switch statement
// for the chunk type you want to react to.
//
long CLoader3DS::EatChunk(char* buffer)
{
    unsigned short   chunkid;
    long    chunklength;
    int     i = 0;  // index into current chunk
    int     j;
    char name[128];
    int pos;
    int temp;
    chunkid = *(unsigned short*)(buffer);
    chunklength = *(long*)(buffer+2);
    i = 6;
    switch (chunkid)
    {
    case 0x4D4D:    // main file
        while ((*(unsigned short*)(buffer+i) != 0x3D3D) &&
            (*(unsigned short*)(buffer+i) != 0xB000))
            i += 2;
        break;
    case 0x3D3D:    // editor data
        break;
    case 0x4000:    // object description
        m_pCurrentMesh = new CMesh();
        ZeroMemory( m_pCurrentMesh, sizeof(CMesh) );
        m_pCurrentMesh->m_strName = ( (char*)(buffer+i) );
        m_pCurrentObject->AddMesh( m_pCurrentMesh );
        while (*(buffer+(i++)) != 0); // get past string description
        break;
    case 0x4100:    // triangular polygon list
        break;
    case 0x4110:    // vertex list
        if (m_pCurrentMesh == NULL)
        {
            i = chunklength;
            break;
        }
        if (m_pCurrentMesh->m_dwVertexCount == 0)
        {
            m_pCurrentMesh->m_dwVertexCount = *(unsigned short*)(buffer+i);
            i+=2;
            m_pCurrentMesh->m_pVertices = new CVertex[m_pCurrentMesh->m_dwVertexCount];
            ZeroMemory( m_pCurrentMesh->m_pVertices, m_pCurrentMesh->m_dwVertexCount * sizeof(CVertex) );
            for (j=0;j<m_pCurrentMesh->m_dwVertexCount;j++)
            {
                m_pCurrentMesh->m_pVertices[j].x = *(float*)(buffer+i);
                i+=4;
                m_pCurrentMesh->m_pVertices[j].z = *(float*)(buffer+i);
                i+=4;
                m_pCurrentMesh->m_pVertices[j].y = *(float*)(buffer+i);
                i+=4;
            }
        }
        else
            i = chunklength;
        break;
    case 0x4120:
        if (m_pCurrentMesh == NULL)
        {
            i = chunklength;
            break;
        }
        if (m_pCurrentMesh->m_dwIndexCount == 0)
        {
            m_pCurrentMesh->m_dwIndexCount = *(unsigned short*)(buffer+i);
            m_pCurrentMesh->m_dwIndexCount *= 3;
            i+=2;
            m_pCurrentMesh->m_pIndices = new unsigned short[m_pCurrentMesh->m_dwIndexCount];
            ZeroMemory( m_pCurrentMesh->m_pIndices, m_pCurrentMesh->m_dwIndexCount * sizeof(unsigned short) );
            for (j=0;j<m_pCurrentMesh->m_dwIndexCount/3;j++)
            {
                m_pCurrentMesh->m_pIndices[ j*3 + 0 ] = *(unsigned short*)(buffer+i);
                i+=2;
                m_pCurrentMesh->m_pIndices[ j*3 + 1 ] = *(unsigned short*)(buffer+i);
                i+=2;
                m_pCurrentMesh->m_pIndices[ j*3 + 2 ] = *(unsigned short*)(buffer+i);
                i+=2;
                i+=2;   // skip face info
            }
        }
        else
            i = chunklength;
        break;
    case 0x4130:
        if (m_pCurrentMesh == NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMesh->m_strMaterialName = (char*)(buffer+i);
        while (*(buffer+(i++)) != 0); // get past string description
        temp = *(short*)(buffer+i);
        i += sizeof(short) * temp;
        break;
    case 0x4140:
        if (m_pCurrentMesh == NULL)
        {
            i = chunklength;
            break;
        }
        if (m_pCurrentMesh->m_dwVertexCount!=0)
        {
            temp = *(short*)(buffer+i);
            i+=2;
            for( int j=0; j<temp; j++ )
            {
                m_pCurrentMesh->m_pVertices[ j ].tu = *(float*)(buffer+i);
                i+=4;
                m_pCurrentMesh->m_pVertices[ j ].tv = *(float*)(buffer+i);
                i+=4;
                m_pCurrentMesh->m_pVertices[ j ].tu *= -1.0f;
            }
        }
        else
            i = chunklength;
        break;
    case 0xAFFF:
        m_pCurrentMaterial = new CMaterial();
        m_pCurrentObject->AddMaterial( m_pCurrentMaterial );
        m_pCurrentMaterial->m_fUScale = 1.0f;
        m_pCurrentMaterial->m_fVScale = 1.0f;
        break;
    case 0xA000:
        if (m_pCurrentMaterial==NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMaterial->m_strName = (char*)(buffer+i);
        while (*(buffer+(i++)) != 0); // get past string description
        break;
    case 0xA200:
        if (m_pCurrentMaterial==NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMaterial->m_bHasTexture = true;
        break;
    case 0xA300:
        if (m_pCurrentMaterial==NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMaterial->m_strTextureName = (char*)(buffer+i);
        while (*(buffer+(i++)) != 0); // get past string description
        break;
    case 0xA354:
        if (m_pCurrentMaterial==NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMaterial->m_fVScale = *(float*)(buffer+i);
        i+=4;
        break;
    case 0xA356:
        if (m_pCurrentMaterial==NULL)
        {
            i = chunklength;
            break;
        }
        m_pCurrentMaterial->m_fUScale = *(float*)(buffer+i);
        i+=4;
        break;
    default:
        i = chunklength;    // skips over rest of chunk (ignores it)
        break;
    }
    // eat child chunks
    while (i < chunklength)
        i += EatChunk(buffer+i);
    return chunklength;
}

						