GARbro-mirror/ArcFormats/DirectDraw/DxtDecoder.cs
2017-12-15 01:02:54 +04:00

209 lines
7.5 KiB
C#

//! \file DxtDecoder.cs
//! \date Fri Apr 14 07:34:50 2017
//! \brief DXT decompressor.
//
// Copyright (C) 2016-2017 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using GameRes.Utility;
namespace GameRes.Formats.DirectDraw
{
public class DxtDecoder
{
byte[] m_input;
byte[] m_output;
int m_width;
int m_height;
int m_output_stride;
public DxtDecoder (byte[] input, ImageMetaData info)
{
m_input = input;
m_width = (int)info.Width;
m_output_stride = m_width * 4;
m_height = (int)info.Height;
m_output = new byte[m_output_stride*m_height];
}
public byte[] UnpackDXT1 ()
{
int src = 0;
for (int y = 0; y < m_height; y += 4)
for (int x = 0; x < m_width; x += 4)
{
DecompressDXT1Block (m_input, src, y, x);
src += 8;
}
return m_output;
}
public byte[] UnpackDXT5 ()
{
int src = 0;
for (int y = 0; y < m_height; y += 4)
for (int x = 0; x < m_width; x += 4)
{
DecompressDXT5Block (m_input, src, y, x);
src += 16;
}
return m_output;
}
byte[] m_dxt_buffer = new byte[16];
void DecompressDXT1Block (byte[] input, int src, int block_y, int block_x)
{
ReadDXT1Color (input, src, 0);
ReadDXT1Color (input, src+2, 4);
bool has_alpha = m_dxt_buffer[0] <= m_dxt_buffer[4]
&& m_dxt_buffer[1] <= m_dxt_buffer[5]
&& m_dxt_buffer[2] <= m_dxt_buffer[6];
for (int i = 0; i < 4; ++i)
{
if (has_alpha)
{
m_dxt_buffer[8+i] = (byte)((m_dxt_buffer[i] + m_dxt_buffer[4+i]) >> 1);
m_dxt_buffer[12+i] = 0;
}
else
{
m_dxt_buffer[8+i] = (byte)(((m_dxt_buffer[i] << 1) + m_dxt_buffer[4+i]) / 3);
m_dxt_buffer[12+i] = (byte)(((m_dxt_buffer[4+i] << 1) + m_dxt_buffer[i]) / 3);
}
}
uint map = LittleEndian.ToUInt32 (input, src+4);
for (int y = 0; y < 4 && (block_y + y) < m_height; ++y)
for (int x = 0; x < 4 && (block_x + x) < m_width; ++x)
{
int color = (int)(map & 3) << 2;
int dst = m_output_stride * (block_y + y) + (block_x + x) * 4;
m_output[dst] = m_dxt_buffer[color];
m_output[dst+1] = m_dxt_buffer[color+1];
m_output[dst+2] = m_dxt_buffer[color+2];
m_output[dst+3] = m_dxt_buffer[color+3];
map >>= 2;
}
}
void ReadDXT1Color (byte[] input, int src, int idx)
{
int b = input[src] & 0x1F;
int g = (input[src] >> 5 | input[src+1] << 3) & 0x3F;
int r = input[src+1] >> 3;
m_dxt_buffer[idx ] = (byte)(b << 3 | b >> 2);
m_dxt_buffer[idx+1] = (byte)(g << 2 | g >> 4);
m_dxt_buffer[idx+2] = (byte)(r << 3 | r >> 2);
m_dxt_buffer[idx+3] = 0xFF;
}
void DecompressDXT5Block (byte[] input, int src, int block_y, int block_x)
{
byte alpha0 = input[src];
byte alpha1 = input[src+1];
DecompressDXT5Alpha (input, src+2, m_dxt_buffer);
ushort color0 = LittleEndian.ToUInt16 (input, src+8);
ushort color1 = LittleEndian.ToUInt16 (input, src+10);
int t = (color0 >> 11) * 255 + 16;
byte r0 = (byte)((t / 32 + t) / 32);
t = ((color0 & 0x07E0) >> 5) * 255 + 32;
byte g0 = (byte)((t / 64 + t) / 64);
t = (color0 & 0x001F) * 255 + 16;
byte b0 = (byte)((t / 32 + t) / 32);
t = (color1 >> 11) * 255 + 16;
byte r1 = (byte)((t / 32 + t) / 32);
t = ((color1 & 0x07E0) >> 5) * 255 + 32;
byte g1 = (byte)((t / 64 + t) / 64);
t = (color1 & 0x001F) * 255 + 16;
byte b1 = (byte)((t / 32 + t) / 32);
uint code = LittleEndian.ToUInt32 (input, src+12);
for (int y = 0; y < 4 && (block_y + y) < m_height; ++y)
for (int x = 0; x < 4 && (block_x + x) < m_width; ++x)
{
int alpha_code = m_dxt_buffer[4 * y + x];
byte alpha;
if (0 == alpha_code)
alpha = alpha0;
else if (1 == alpha_code)
alpha = alpha1;
else if (alpha0 > alpha1)
alpha = (byte)(((8 - alpha_code) * alpha0 + (alpha_code - 1) * alpha1) / 7);
else if (6 == alpha_code)
alpha = 0;
else if (7 == alpha_code)
alpha = 0xFF;
else
alpha = (byte)(((6 - alpha_code) * alpha0 + (alpha_code - 1) * alpha1) / 5);
int dst = m_output_stride * (block_y + y) + (block_x + x) * 4;
switch (code & 3)
{
case 0:
PutPixel (dst, r0, g0, b0, alpha);
break;
case 1:
PutPixel (dst, r1, g1, b1, alpha);
break;
case 2:
PutPixel (dst, (byte)((2 * r0 + r1) / 3), (byte)((2 * g0 + g1) / 3), (byte)((2 * b0 + b1) / 3), alpha);
break;
case 3:
PutPixel (dst, (byte)((r0 + 2 * r1) / 3), (byte)((g0 + 2 * g1) / 3), (byte)((b0 + 2 * b1) / 3), alpha);
break;
}
code >>= 2;
}
}
static void DecompressDXT5Alpha (byte[] input, int src, byte[] output)
{
int dst = 0;
for (int j = 0; j < 2; ++j)
{
int block = input[src++];
block |= input[src++] << 8;
block |= input[src++] << 16;
for (int i = 0; i < 8; ++i)
{
output[dst++] = (byte)(block & 7);
block >>= 3;
}
}
}
void PutPixel (int dst, byte r, byte g, byte b, byte a)
{
m_output[dst] = b;
m_output[dst+1] = g;
m_output[dst+2] = r;
m_output[dst+3] = a;
}
}
}