//Only called when creating new rgba value. Traverses the Huffman tree to return the correct value
private static int RetrieveHuffmanTreeValue(byte[] data, TKMK00HuffmanTreeNode currentNode, TKMK00CommandReader commandReader)
{
while (!currentNode.IsEndNode)/*currentNode.Value >= 0x20*/
{
int command = commandReader.ReadBits(1); // 0 - left, 1 - right
if (command == 0)
currentNode = currentNode.Left;
else
currentNode = currentNode.Right;
}
return currentNode.Value;
}
/// <summary>
/// Creates a Huffman-style binary tree that holds the 5-bit color data referenced in the
/// TKMK00 decoding process.
/// </summary>
private static TKMK00HuffmanTreeNode SetUpHuffmanTree(uint val, byte[] data, TKMK00CommandReader commandReader)
{
TKMK00HuffmanTreeNode newTree = new TKMK00HuffmanTreeNode();
int command = commandReader.ReadBits(1);//1 - Make new branches, 0 - End current branch
if (command != 0)
{
newTree.Value = (int)val; //Not used, but can't hurt to number it
val++;
newTree.Left = SetUpHuffmanTree(val, data, commandReader);
newTree.Right = SetUpHuffmanTree(val, data, commandReader);
return newTree;
}
//Else, return a node with a value
int value = 0;
int bitCount = 5;
do
{
command = commandReader.ReadBits(1);
value = value * 2 + command; //basically bitshifts s0 to the left and adds v0, aka it's loading 5 bytes straight from the comandReader
bitCount -= 1;
} while (bitCount > 0);
newTree.Value = value;
return newTree;
}
/// <summary>
/// Decodes the TKMK00 format into RGBA5551 formatted data. Uses a Huffman tree to store
/// color values that are added/subtracted/sometimes overwrite a predicted color for the
/// current pixel. Look up DPCM for a conceptual idea of what it's doing (the Huffman tree
/// stands in place for entropy coding.
/// </summary>
public static byte[] Decode(byte[] data, int tkmk00Offset, ushort alphaColor)
{
//Initialize the header & readers
byte[] headerBytes = new byte[TKMK00Header.DataSize];
Array.Copy(data, tkmk00Offset, headerBytes, 0, TKMK00Header.DataSize);
TKMK00Header header = new TKMK00Header(headerBytes);
TKMK00CommandReader masterReader = new TKMK00CommandReader(data, tkmk00Offset + TKMK00Header.DataSize, false);
TKMK00CommandReader[] channelReaders = new TKMK00CommandReader[8];
for(int i = 0; i < 8; i++)
channelReaders[i] = new TKMK00CommandReader(data, tkmk00Offset + header.ChannelPointers[i], header.RepeatEnabledFor(i));
//Set up the image data/buffers
ushort[] rgbaBuffer = new ushort[0x40];
for (int i = 0; i < 0x40; i++)
rgbaBuffer[i] = 0xFF;
byte[] colorChangeMap = new byte[header.Width * header.Height];
byte[] imageData = new byte[header.Width * header.Height * 2];
int pixelIndex = 0;
//Set up the Huffman binary tree
TKMK00HuffmanTreeNode headTreeNode = SetUpHuffmanTree(0x20, data, channelReaders[0]);
ushort lastPixelColor = 0;
//Iterate through each pixel in order left to right, top to bottom
for (int row = 0; row < header.Height; row++)
{
for (int col = 0; col < header.Width; col++)
{
//Look at the current pixel's color. If it's not empty, then it's already been
// set to its correct value, and we can skip to the next pixel
ushort currentPixelColor = ByteHelper.ReadUShort(imageData, pixelIndex * 2);
if (currentPixelColor != 0) //Color already exists
{
lastPixelColor = currentPixelColor;
//Test to make sure that the curent color is not the alpha value with the incorrect alpha channel value
ushort currentPixelWithoutAlpha = (ushort)(currentPixelColor & 0xFFFE);
if (currentPixelWithoutAlpha == alphaColor)
{
ByteHelper.WriteUShort(alphaColor, imageData, pixelIndex * 2);
lastPixelColor = alphaColor;
}
//Done, go to end of the loop
}
else
{
//Load up the channel reader that is associated with the given color change value in the
// colorChangeMap (low values = not much change around that pixel, high values = lots of change)
byte channelIndex = (byte)(colorChangeMap[pixelIndex] + 1);
int command = channelReaders[channelIndex].ReadBits(1); // 0 - Use the previous color, 1 - Use new color
if (command == 0)
{
ByteHelper.WriteUShort(lastPixelColor, imageData, pixelIndex * 2);
//End of this line
}
else
{
command = masterReader.ReadBits(1); // 1 - Create new RGBA, 0 - Use existing RGBA
if (command != 0)
{
//Load in the huffman values for the new green, red and blue. These are combined
// with a predicted pixel value for them later on.
int newGreen = RetrieveHuffmanTreeValue(data, headTreeNode, channelReaders[0]);
int newRed = RetrieveHuffmanTreeValue(data, headTreeNode, channelReaders[0]);
int newBlue = RetrieveHuffmanTreeValue(data, headTreeNode, channelReaders[0]);
//Retreive the pixel colors from the pixel above and the pixel to the left
ushort rgbaTop, rgbaLeft;
if (row != 0)
{
rgbaTop = ByteHelper.ReadUShort(imageData, (pixelIndex - header.Width) * 2);
rgbaLeft = ByteHelper.ReadUShort(imageData, (pixelIndex - 1) * 2);
}
else
{
rgbaTop = 0;
if (col != 0)
rgbaLeft = ByteHelper.ReadUShort(imageData, (pixelIndex - 1) * 2);
else
rgbaLeft = 0;
}
//Combine green values of the pixels to make our predicted pixel color
ushort greenTop = (byte)((rgbaTop & 0x7C0) >> 6);
ushort greenLeft = (byte)((rgbaLeft & 0x7C0) >> 6);
int greenPrediction = (greenTop + greenLeft) / 2;
//Combine the prediction & huffman value to make the output color
ColorCombine(greenPrediction, ref newGreen);
//Use the change between the old & new green values to project expected
// values for the red & blue colors
int greenChange = newGreen - greenPrediction;
//Combine red values of the pixels to make our predicted pixel color
ushort redTop = (byte)((rgbaTop & 0xF800) >> 11);
ushort redLeft = (byte)((rgbaLeft & 0xF800) >> 11);
int redPrediction = greenChange + (redTop + redLeft) / 2;
redPrediction = Math.Max(0, Math.Min(0x1F, redPrediction)); //Keep between 0 and 0x1F
//Combine the prediction & huffman value to make the output color
ColorCombine(redPrediction, ref newRed);
//Combine blue values of the pixels to make our predicted pixel color
ushort blueTop = (byte)((rgbaTop & 0x3E) >> 1);
ushort blueLeft = (byte)((rgbaLeft & 0x3E) >> 1);
int bluePrediction = greenChange + (blueTop + blueLeft) / 2;
bluePrediction = Math.Max(0, Math.Min(0x1F, bluePrediction)); //Keep between 0 and 0x1F
//Combine the prediction & huffman value to make the output color
ColorCombine(bluePrediction, ref newBlue);
//Make the newpixel color
currentPixelColor = (ushort)((newRed << 11) | (newGreen << 6) | (newBlue << 1));
if (currentPixelColor != alphaColor) //Only transparent if it matches the transparency pixel
currentPixelColor |= 0x1;
//Add to the front of the color buffer
for (int i = rgbaBuffer.Length - 1; i > 0; i--)
rgbaBuffer[i] = rgbaBuffer[i - 1];
rgbaBuffer[0] = currentPixelColor;
}
else //Use existing RGBA
{
command = masterReader.ReadBits(6); // Returns index of color in color buffer to use
currentPixelColor = rgbaBuffer[command];
if (command != 0)
{
//Bump the selected color to the front of the buffer
for (int i = command; i > 0; i--)
rgbaBuffer[i] = rgbaBuffer[i - 1];
rgbaBuffer[0] = currentPixelColor;
}
}
//Write the RGBA to the imageData
ByteHelper.WriteUShort(currentPixelColor, imageData, pixelIndex * 2);
lastPixelColor = currentPixelColor;
//Add nearby pixels to the colorChangeMap
bool hasLeftCol = (col != 0);
bool hasRightCol = (col < (header.Width - 1));
bool has2RightCols = (col < (header.Width - 2));
bool hasDownRow = (row < (header.Height - 1));
bool has2DownRows = (row < (header.Height - 2));
//Right 1
if (hasRightCol)
colorChangeMap[pixelIndex + 1]++;
//Right 2
if (has2RightCols)
colorChangeMap[pixelIndex + 2]++;
//Down 1 Left 1
if (hasDownRow && hasLeftCol)
colorChangeMap[pixelIndex + header.Width - 1]++;
//Down 1
if (hasDownRow)
colorChangeMap[pixelIndex + header.Width]++;
//Down 1 Right 1
if (hasDownRow && hasRightCol)
colorChangeMap[pixelIndex + header.Width + 1]++;
//Down 2
if (has2DownRows)
colorChangeMap[pixelIndex + header.Width * 2]++;
//Now test to see if we need to continue writing this color down the column
command = masterReader.ReadBits(1);//1 - repeat color, 0 - continue
if (command == 1) //Repeat color
{
//Basically move down one row each repeat, possibly moving to the side, and write the color again
int pixelOffset = 0;
ushort currentPixelColorOpaque = (ushort)(currentPixelColor | 0x1); //Not sure why this is the case, is it to catch it in the first if statement?
while(true) //I hate while(true)
{
command = masterReader.ReadBits(2);//0 - advanced move, 1 - back one, 2 - no lateral move, 3 - forward one
if (command == 0)
{
//Advanced move
command = masterReader.ReadBits(1);//0 - stop, 1 - advanced move
if (command == 0)
{
break;
}
command = masterReader.ReadBits(1); //0 - move back 2, 1 - move forward 2
if (command == 0)
{
pixelOffset -= 2;
}
else
{
pixelOffset += 2;
}
}
else if (command == 1)
{
pixelOffset--;
}
else if (command == 3)
{
pixelOffset++;
}
pixelOffset += header.Width; //move down a row
ByteHelper.WriteUShort(currentPixelColorOpaque, imageData, (pixelIndex + pixelOffset) * 2);
}
}
}
}
//Next pixel
pixelIndex++;
}
}
return imageData;
}