protected override void Initalize()
{
// Check to see if what we are dealing with is a PVR texture
if (!Is(encodedData))
{
throw new NotAValidTextureException("This is not a valid PVR texture.");
}
// Determine the offsets of the GBIX (if present) and PVRT header chunks.
if (PTMethods.Contains(encodedData, 0x00, gbixFourCC))
{
gbixOffset = 0x00;
pvrtOffset = 0x08 + BitConverter.ToInt32(encodedData, gbixOffset + 4);
}
else if (PTMethods.Contains(encodedData, 0x04, gbixFourCC))
{
gbixOffset = 0x04;
pvrtOffset = 0x0C + BitConverter.ToInt32(encodedData, gbixOffset + 4);
}
else if (PTMethods.Contains(encodedData, 0x04, pvrtFourCC))
{
gbixOffset = -1;
pvrtOffset = 0x04;
}
else
{
gbixOffset = -1;
pvrtOffset = 0x00;
}
// Read the global index (if it is present). If it is not present, just set it to 0.
if (gbixOffset != -1)
{
globalIndex = BitConverter.ToUInt32(encodedData, gbixOffset + 0x08);
}
else
{
globalIndex = 0;
}
// Read information about the texture
textureWidth = BitConverter.ToUInt16(encodedData, pvrtOffset + 0x0C);
textureHeight = BitConverter.ToUInt16(encodedData, pvrtOffset + 0x0E);
pixelFormat = (PvrPixelFormat)encodedData[pvrtOffset + 0x08];
dataFormat = (PvrDataFormat)encodedData[pvrtOffset + 0x09];
// Get the codecs and make sure we can decode using them
pixelCodec = PvrPixelCodec.GetPixelCodec(pixelFormat);
dataCodec = PvrDataCodec.GetDataCodec(dataFormat);
if (dataCodec != null && pixelCodec != null)
{
dataCodec.PixelCodec = pixelCodec;
canDecode = true;
}
// Set the number of palette entries
// The number in a Small Vq encoded texture various based on its size
paletteEntries = dataCodec.PaletteEntries;
if (dataFormat == PvrDataFormat.SmallVq)
{
if (textureWidth <= 16)
{
paletteEntries = 64; // Actually 16
}
else if (textureWidth <= 32)
{
paletteEntries = 128; // Actually 32
}
else if (textureWidth <= 64)
{
paletteEntries = 512; // Actually 128
}
else
{
paletteEntries = 1024; // Actually 256
}
}
else if (dataFormat == PvrDataFormat.SmallVqMipmaps)
{
if (textureWidth <= 16)
{
paletteEntries = 64; // Actually 16
}
else if (textureWidth <= 32)
{
paletteEntries = 256; // Actually 64
}
else
{
paletteEntries = 1024; // Actually 256
}
}
// Set the palette and data offsets
if (!canDecode || paletteEntries == 0 || dataCodec.NeedsExternalPalette)
{
paletteOffset = -1;
dataOffset = pvrtOffset + 0x10;
}
else
{
paletteOffset = pvrtOffset + 0x10;
dataOffset = paletteOffset + (paletteEntries * (pixelCodec.Bpp >> 3));
}
// Get the compression format and determine if we need to decompress this texture
compressionFormat = GetCompressionFormat(encodedData, pvrtOffset, dataOffset);
compressionCodec = PvrCompressionCodec.GetCompressionCodec(compressionFormat);
if (compressionFormat != PvrCompressionFormat.None && compressionCodec != null)
{
encodedData = compressionCodec.Decompress(encodedData, dataOffset, pixelCodec, dataCodec);
// Now place the offsets in the appropiate area
if (compressionFormat == PvrCompressionFormat.Rle)
{
if (gbixOffset != -1)
{
gbixOffset -= 4;
}
pvrtOffset -= 4;
if (paletteOffset != -1)
{
paletteOffset -= 4;
}
dataOffset -= 4;
}
}
// If the texture contains mipmaps, gets the offsets of them
if (canDecode && dataCodec.HasMipmaps)
{
mipmapOffsets = new int[(int)Math.Log(textureWidth, 2) + 1];
int mipmapOffset = 0;
// Calculate the padding for the first mipmap offset
if (dataFormat == PvrDataFormat.SquareTwiddledMipmaps)
{
// A 1x1 mipmap takes up as much space as a 2x1 mipmap
mipmapOffset = (dataCodec.Bpp) >> 3;
}
else if (dataFormat == PvrDataFormat.SquareTwiddledMipmapsAlt)
{
// A 1x1 mipmap takes up as much space as a 2x2 mipmap
mipmapOffset = (3 * dataCodec.Bpp) >> 3;
}
for (int i = mipmapOffsets.Length - 1, size = 1; i >= 0; i--, size <<= 1)
{
mipmapOffsets[i] = mipmapOffset;
mipmapOffset += Math.Max((size * size * dataCodec.Bpp) >> 3, 1);
}
}
initalized = true;
}
protected override MemoryStream EncodeTexture()
{
// Calculate what the length of the texture will be
int textureLength = 16 + (textureWidth * textureHeight * dataCodec.Bpp / 8);
if (hasGlobalIndex)
{
textureLength += 16;
}
if (dataCodec.PaletteEntries != 0 && !dataCodec.NeedsExternalPalette)
{
textureLength += (dataCodec.PaletteEntries * pixelCodec.Bpp / 8);
}
// Calculate the mipmap padding (if the texture contains mipmaps)
int mipmapPadding = 0;
if (dataCodec.HasMipmaps)
{
if (dataFormat == PvrDataFormat.SquareTwiddledMipmaps)
{
// A 1x1 mipmap takes up as much space as a 2x1 mipmap
// There are also 4 extra bytes at the end of the file
mipmapPadding = (dataCodec.Bpp) >> 3;
textureLength += 4;
}
else if (dataFormat == PvrDataFormat.SquareTwiddledMipmapsAlt)
{
// A 1x1 mipmap takes up as much space as a 2x2 mipmap
mipmapPadding = (3 * dataCodec.Bpp) >> 3;
}
textureLength += mipmapPadding;
for (int size = 1; size < textureWidth; size <<= 1)
{
textureLength += Math.Max((size * size * dataCodec.Bpp) >> 3, 1);
}
}
MemoryStream destination = new MemoryStream(textureLength);
// Write out the GBIX header (if we are including one)
if (hasGlobalIndex)
{
destination.WriteByte((byte)'G');
destination.WriteByte((byte)'B');
destination.WriteByte((byte)'I');
destination.WriteByte((byte)'X');
PTStream.WriteUInt32(destination, 8);
PTStream.WriteUInt32(destination, globalIndex);
PTStream.WriteUInt32(destination, 0);
}
// Write out the PVRT header
destination.WriteByte((byte)'P');
destination.WriteByte((byte)'V');
destination.WriteByte((byte)'R');
destination.WriteByte((byte)'T');
if (hasGlobalIndex)
{
PTStream.WriteInt32(destination, textureLength - 24);
}
else
{
PTStream.WriteInt32(destination, textureLength - 8);
}
destination.WriteByte((byte)pixelFormat);
destination.WriteByte((byte)dataFormat);
PTStream.WriteUInt16(destination, 0);
PTStream.WriteUInt16(destination, textureWidth);
PTStream.WriteUInt16(destination, textureHeight);
// If we have an internal palette, write it
if (dataCodec.PaletteEntries != 0 && !dataCodec.NeedsExternalPalette)
{
byte[] palette = pixelCodec.EncodePalette(texturePalette, dataCodec.PaletteEntries);
destination.Write(palette, 0, palette.Length);
}
// Write out any mipmaps
if (dataCodec.HasMipmaps)
{
// Write out any padding bytes before the 1x1 mipmap
for (int i = 0; i < mipmapPadding; i++)
{
destination.WriteByte(0);
}
for (int size = 1; size < textureWidth; size <<= 1)
{
byte[] mipmapDecodedData = BitmapToRawResized(decodedBitmap, size, 1);
byte[] mipmapTextureData = dataCodec.Encode(mipmapDecodedData, 0, size, size);
destination.Write(mipmapTextureData, 0, mipmapTextureData.Length);
}
}
// Write the texture data
byte[] textureData = dataCodec.Encode(decodedData, textureWidth, textureHeight, null);
destination.Write(textureData, 0, textureData.Length);
// If the data format is square twiddled with mipmaps, write out the extra bytes.
if (dataFormat == PvrDataFormat.SquareTwiddledMipmaps)
{
destination.Write(new byte[] { 0, 0, 0, 0 }, 0, 4);
}
// Compress the texture
if (compressionFormat != PvrCompressionFormat.None)
{
compressionCodec = PvrCompressionCodec.GetCompressionCodec(compressionFormat);
if (compressionCodec != null)
{
// Ok, we need to convert the current stream to an array, compress it, then write it back to a new stream
byte[] buffer = destination.ToArray();
buffer = compressionCodec.Compress(buffer, (hasGlobalIndex ? 0x20 : 0x10), pixelCodec, dataCodec);
destination = new MemoryStream();
destination.Write(buffer, 0, buffer.Length);
}
}
return(destination);
}
