PVR file loader for OGL

pvr.h

#define PVR_RGBA8	0x61626772
#define PVR_PVRTC4	0x00000002
#define PVR_ETC1	0x00000006
#define PVR_BC1		0x00000007
#define PVR_ALPHA	0x00000061

#define GL_COMPRESSED_RGB_S3TC_DXT1     0x83F0
#define	GL_ETC1_RGB8_OES                0x8D64
#define GL_COMPRESSED_RGB_PVRTC_4BPPV1  0x8C00

Texture::Texture(Stream *stream, int param) : ResObject(stream, param), width(0), height(0), depth(false) {
	struct {
		int  version;
		int  flags;
		long format;
		long ext;
		int  color;
		int  channel;
		int  height;
		int  width;
		int  depth;
		int  surfaces;
		int  faces;
		int  mipCount;
		int  metaSize;
	} header;

	stream->read(&header, sizeof(header));
	stream->seek(header.metaSize);

	GLenum fmt, minSize;
	switch (header.format) {
		case PVR_ALPHA  : minSize = 1; fmt = GL_ALPHA; break;
		case PVR_RGBA8	: minSize = 1; fmt = GL_RGBA; break;
		case PVR_BC1	: minSize = 4; fmt = GL_COMPRESSED_RGB_S3TC_DXT1; break;
		case PVR_ETC1	: minSize = 4; fmt = GL_ETC1_RGB8_OES; break;
		case PVR_PVRTC4	: minSize = 8; fmt = GL_COMPRESSED_RGB_PVRTC_4BPPV1; break;
		default			: ASSERT(false);
	}

	int sizeX	= width = header.width;
	int sizeY	= height = header.height;

	glGenTextures(1, &ID);
	setFilter(tfAniso);

	char *data = new char[width * height * 4];
	for (int i = 0; i < header.mipCount; i++) {

		if (header.format == PVR_RGBA8 || header.format == PVR_ALPHA) {
			stream->read(data, sizeX * sizeY * (header.format == PVR_RGBA8 ? 4 : 1));
			glTexImage2D(GL_TEXTURE_2D, i, fmt, sizeX, sizeY, 0, fmt, GL_UNSIGNED_BYTE, data);
		} else {
			int size = (_max(sizeX, minSize) * _max(sizeY, minSize) * 4 + 7) / 8;
			stream->read(data, size);
			glCompressedTexImage2D(GL_TEXTURE_2D, i, fmt, sizeX, sizeY, 0, size, data);
		}

		sizeX >>= 1;
		sizeY >>= 1;
	}

	delete[] data;
}