nv_dds.cpp

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    GLenum target;

    // loop through cubemap faces and load them as 2D textures 
    for (unsigned int n = 0; n < 6; n++)
    {
        // specify cubemap face
        target = GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB + n;
        if (!upload_texture2D(n, target))
            return false;
    }

    return true;
}

#endif // !BITMAP_NO_OPENGL

///////////////////////////////////////////////////////////////////////////////
// clamps input size to [1-size]
inline unsigned int CDDSImage::clamp_size(unsigned int size)
{
    if (size <= 0)
        size = 1;

    return size;
}

///////////////////////////////////////////////////////////////////////////////
// CDDSImage private functions
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
// calculates size of DXTC texture in bytes
inline unsigned int CDDSImage::size_dxtc(unsigned int width, unsigned int height)
{
    return ((width+3)/4)*((height+3)/4)*
        (m_format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT ? 8 : 16);   
}

///////////////////////////////////////////////////////////////////////////////
// calculates size of uncompressed RGB texture in bytes
inline unsigned int CDDSImage::size_rgb(unsigned int width, unsigned int height)
{
    return width*height*m_components;
}

///////////////////////////////////////////////////////////////////////////////
// flip image around X axis
void CDDSImage::flip(CSurface &surface)
{
    unsigned int linesize;
    unsigned int offset;

    if (!is_compressed())
    {
        assert(surface.get_depth() > 0);

        unsigned int imagesize = surface.get_size()/surface.get_depth();
        linesize = imagesize / surface.get_height();

        for (unsigned int n = 0; n < surface.get_depth(); n++)
        {
            offset = imagesize*n;
            unsigned char *top = (unsigned char*)surface + offset;
            unsigned char *bottom = top + (imagesize-linesize);
    
            for (unsigned int i = 0; i < (surface.get_height() >> 1); i++)
            {
                swap(bottom, top, linesize);

                top += linesize;
                bottom -= linesize;
            }
        }
    }
    else
    {
        void (CDDSImage::*flipblocks)(DXTColBlock*, unsigned int);
        unsigned int xblocks = surface.get_width() / 4;
        unsigned int yblocks = surface.get_height() / 4;
        unsigned int blocksize;

        switch (m_format)
        {
            case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT: 
                blocksize = 8;
                flipblocks = &CDDSImage::flip_blocks_dxtc1; 
                break;
            case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT: 
                blocksize = 16;
                flipblocks = &CDDSImage::flip_blocks_dxtc3; 
                break;
            case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT: 
                blocksize = 16;
                flipblocks = &CDDSImage::flip_blocks_dxtc5; 
                break;
            default:
                return;
        }

        linesize = xblocks * blocksize;

        DXTColBlock *top;
        DXTColBlock *bottom;
    
        for (unsigned int j = 0; j < (yblocks >> 1); j++)
        {
            top = (DXTColBlock*)((unsigned char*)surface+ j * linesize);
            bottom = (DXTColBlock*)((unsigned char*)surface + (((yblocks-j)-1) * linesize));

            (this->*flipblocks)(top, xblocks);
            (this->*flipblocks)(bottom, xblocks);

            swap(bottom, top, linesize);
        }
    }
}    

void CDDSImage::flip_texture(CTexture &texture)
{
    flip(texture);
    
    for (unsigned int i = 0; i < texture.get_num_mipmaps(); i++)
    {
        flip(texture.get_mipmap(i));
    }
}

///////////////////////////////////////////////////////////////////////////////
// swap to sections of memory
void CDDSImage::swap(void *byte1, void *byte2, unsigned int size)
{
    unsigned char *tmp = SAFE_NEW unsigned char[size];

    memcpy(tmp, byte1, size);
    memcpy(byte1, byte2, size);
    memcpy(byte2, tmp, size);

    delete [] tmp;
}

///////////////////////////////////////////////////////////////////////////////
// flip a DXT1 color block
void CDDSImage::flip_blocks_dxtc1(DXTColBlock *line, unsigned int numBlocks)
{
    DXTColBlock *curblock = line;

    for (unsigned int i = 0; i < numBlocks; i++)
    {
        swap(&curblock->row[0], &curblock->row[3], sizeof(unsigned char));
        swap(&curblock->row[1], &curblock->row[2], sizeof(unsigned char));

        curblock++;
    }
}

///////////////////////////////////////////////////////////////////////////////
// flip a DXT3 color block
void CDDSImage::flip_blocks_dxtc3(DXTColBlock *line, unsigned int numBlocks)
{
    DXTColBlock *curblock = line;
    DXT3AlphaBlock *alphablock;

    for (unsigned int i = 0; i < numBlocks; i++)
    {
        alphablock = (DXT3AlphaBlock*)curblock;

        swap(&alphablock->row[0], &alphablock->row[3], sizeof(unsigned short));
        swap(&alphablock->row[1], &alphablock->row[2], sizeof(unsigned short));

        curblock++;

        swap(&curblock->row[0], &curblock->row[3], sizeof(unsigned char));
        swap(&curblock->row[1], &curblock->row[2], sizeof(unsigned char));

        curblock++;
    }
}

///////////////////////////////////////////////////////////////////////////////
// flip a DXT5 alpha block
void CDDSImage::flip_dxt5_alpha(DXT5AlphaBlock *block)
{
    unsigned char gBits[4][4];
    
    const unsigned int mask = 0x00000007;          // bits = 00 00 01 11
    unsigned int bits = 0;
    memcpy(&bits, &block->row[0], sizeof(unsigned char) * 3);

    gBits[0][0] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[0][1] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[0][2] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[0][3] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[1][0] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[1][1] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[1][2] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[1][3] = (unsigned char)(bits & mask);

    bits = 0;
    memcpy(&bits, &block->row[3], sizeof(unsigned char) * 3);

    gBits[2][0] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[2][1] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[2][2] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[2][3] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[3][0] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[3][1] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[3][2] = (unsigned char)(bits & mask);
    bits >>= 3;
    gBits[3][3] = (unsigned char)(bits & mask);

    unsigned int *pBits = ((unsigned int*) &(block->row[0]));

    *pBits = *pBits | (gBits[3][0] << 0);
    *pBits = *pBits | (gBits[3][1] << 3);
    *pBits = *pBits | (gBits[3][2] << 6);
    *pBits = *pBits | (gBits[3][3] << 9);

    *pBits = *pBits | (gBits[2][0] << 12);
    *pBits = *pBits | (gBits[2][1] << 15);
    *pBits = *pBits | (gBits[2][2] << 18);
    *pBits = *pBits | (gBits[2][3] << 21);

    pBits = ((unsigned int*) &(block->row[3]));

#ifdef MACOS
    *pBits &= 0x000000ff;
#else
    *pBits &= 0xff000000;
#endif

    *pBits = *pBits | (gBits[1][0] << 0);
    *pBits = *pBits | (gBits[1][1] << 3);
    *pBits = *pBits | (gBits[1][2] << 6);
    *pBits = *pBits | (gBits[1][3] << 9);

    *pBits = *pBits | (gBits[0][0] << 12);
    *pBits = *pBits | (gBits[0][1] << 15);
    *pBits = *pBits | (gBits[0][2] << 18);
    *pBits = *pBits | (gBits[0][3] << 21);
}

///////////////////////////////////////////////////////////////////////////////
// flip a DXT5 color block
void CDDSImage::flip_blocks_dxtc5(DXTColBlock *line, unsigned int numBlocks)
{
    DXTColBlock *curblock = line;
    DXT5AlphaBlock *alphablock;
    
    for (unsigned int i = 0; i < numBlocks; i++)
    {
        alphablock = (DXT5AlphaBlock*)curblock;
        
        flip_dxt5_alpha(alphablock);

        curblock++;

        swap(&curblock->row[0], &curblock->row[3], sizeof(unsigned char));
        swap(&curblock->row[1], &curblock->row[2], sizeof(unsigned char));

        curblock++;
    }
}

///////////////////////////////////////////////////////////////////////////////
// CTexture implementation
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
// default constructor
CTexture::CTexture()
  : CSurface()  // initialize base class part
{
}

///////////////////////////////////////////////////////////////////////////////
// creates an empty texture
CTexture::CTexture(unsigned int w, unsigned int h, unsigned int d, unsigned int imgsize, const unsigned char *pixels)
  : CSurface(w, h, d, imgsize, pixels)  // initialize base class part
{
}

CTexture::~CTexture()
{
}

///////////////////////////////////////////////////////////////////////////////
// copy constructor
CTexture::CTexture(const CTexture &copy)
  : CSurface(copy)
{
    for (unsigned int i = 0; i < copy.get_num_mipmaps(); i++)
        m_mipmaps.push_back(copy.get_mipmap(i));
}

///////////////////////////////////////////////////////////////////////////////
// assignment operator
CTexture &CTexture::operator= (const CTexture &rhs)
{
    if (this != &rhs)
    {
        CSurface::operator = (rhs);

        m_mipmaps.clear();
        for (unsigned int i = 0; i < rhs.get_num_mipmaps(); i++)
            m_mipmaps.push_back(rhs.get_mipmap(i));
    }

    return *this;
}

void CTexture::create(unsigned int w, unsigned int h, unsigned int d, unsigned int imgsize, const unsigned char *pixels)
{
    CSurface::create(w, h, d, imgsize, pixels);

    m_mipmaps.clear();
}

void CTexture::clear()
{
    CSurface::clear();

    m_mipmaps.clear();
}

///////////////////////////////////////////////////////////////////////////////
// CSurface implementation
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
// default constructor
CSurface::CSurface()
  : m_width(0),
    m_height(0),
    m_depth(0),
    m_size(0),
    m_pixels(NULL)
{
}

///////////////////////////////////////////////////////////////////////////////
// creates an empty image
CSurface::CSurface(unsigned int w, unsigned int h, unsigned int d, unsigned int imgsize, const unsigned char *pixels)
  : m_width(0),
    m_height(0),
    m_depth(0),
    m_size(0),
    m_pixels(NULL)
{
    create(w, h, d, imgsize, pixels);
}

///////////////////////////////////////////////////////////////////////////////
// copy constructor
CSurface::CSurface(const CSurface &copy)
  : m_width(0),
    m_height(0),
    m_depth(0),
    m_size(0),
    m_pixels(NULL)
{
    if (copy.get_size() != 0)
    {
        m_size = copy.get_size();
        m_width = copy.get_width();
        m_height = copy.get_height();
        m_depth = copy.get_depth();

        m_pixels = SAFE_NEW unsigned char[m_size];
        memcpy(m_pixels, copy, m_size);
    }
}

///////////////////////////////////////////////////////////////////////////////
// assignment operator
CSurface &CSurface::operator= (const CSurface &rhs)
{
    if (this != &rhs)
    {
        clear();

        if (rhs.get_size())
        {
            m_size = rhs.get_size();
            m_width = rhs.get_width();
            m_height = rhs.get_height();
            m_depth = rhs.get_depth();

            m_pixels = SAFE_NEW unsigned char[m_size];
            memcpy(m_pixels, rhs, m_size);
        }
    }

    return *this;
}

///////////////////////////////////////////////////////////////////////////////
// clean up image memory
CSurface::~CSurface()
{
    clear();
}

///////////////////////////////////////////////////////////////////////////////
// returns a pointer to image
CSurface::operator unsigned char*() const
{ 
    return m_pixels; 
}

///////////////////////////////////////////////////////////////////////////////
// creates an empty image
void CSurface::create(unsigned int w, unsigned int h, unsigned int d, unsigned int imgsize, const unsigned char *pixels)
{
    assert(w != 0);
    assert(h != 0);
    assert(d != 0);
    assert(imgsize != 0);
    assert(pixels);

    clear();

    m_width = w;
    m_height = h;
    m_depth = d;
    m_size = imgsize;
    m_pixels = SAFE_NEW unsigned char[imgsize];
    memcpy(m_pixels, pixels, imgsize);
}

///////////////////////////////////////////////////////////////////////////////
// free surface memory
void CSurface::clear()
{
    if (m_pixels != NULL)
    {
        delete [] m_pixels;
        m_pixels = NULL;
    }
}