private unsafe void uploadATFTextureFromByteArray (ByteArray data, uint byteArrayOffset)
{
data.position = byteArrayOffset;
// read atf signature
string signature = data.readUTFBytes(3);
if (signature != "ATF") {
throw new InvalidDataException("ATF signature not found");
}
// read atf length
uint length = readUInt24(data);
if ((byteArrayOffset + length) > data.length) {
throw new InvalidDataException("ATF length exceeds byte array length");
}
// get format
uint tdata = data.readUnsignedByte( );
AtfType type = (AtfType)(tdata >> 7);
if (type != AtfType.NORMAL) {
throw new NotImplementedException("ATF Cube maps are not supported");
}
// Removing ATF format limitation to allow for multiple format support.
// AtfFormat format = (AtfFormat)(tdata & 0x7f);
// if (format != AtfFormat.Block) {
// throw new NotImplementedException("Only ATF block compressed textures are supported");
// }
// get dimensions
int width = (1 << (int)data.readUnsignedByte());
int height = (1 << (int)data.readUnsignedByte());
if (width != mWidth || height != mHeight) {
throw new InvalidDataException("ATF Width and height dont match");
}
// get mipmap count
int mipCount = (int)data.readUnsignedByte();
// read all mipmap levels
for (int level=0; level < mipCount; level++)
{
// read all gpu formats
for (int gpuFormat=0; gpuFormat < 3; gpuFormat++)
{
// read block length
uint blockLength = readUInt24(data);
if ((data.position + blockLength) > data.length) {
throw new System.IO.InvalidDataException("Block length exceeds ATF file length");
}
if (blockLength > 0) {
#if PLATFORM_MONOTOUCH
// handle PVRTC on iOS
if (gpuFormat == 1) {
OpenTK.Graphics.ES20.PixelInternalFormat pixelFormat = (OpenTK.Graphics.ES20.PixelInternalFormat)0x8C02;
fixed(byte *ptr = data.getRawArray())
{
// upload from data position
var address = new IntPtr(ptr + data.position);
GL.CompressedTexImage2D(textureTarget, level, pixelFormat, width, height, 0, (int)blockLength, address);
}
}
#endif
// TODO handle other formats/platforms
}
// next block data
data.position += blockLength;
}
}
}
private static uint readUInt24(ByteArray data)
{
uint value;
value = (data.readUnsignedByte() << 16);
value |= (data.readUnsignedByte() << 8);
value |= data.readUnsignedByte();
return value;
}