(DXT): added DXT1 decoder.

This commit is contained in:
morkt 2017-12-15 01:02:54 +04:00
parent 184b1ce2db
commit 613481d391

View File

@ -2,7 +2,7 @@
//! \date Fri Apr 14 07:34:50 2017
//! \brief DXT decompressor.
//
// Copyright (C) 2016 by morkt
// 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
@ -44,6 +44,18 @@ namespace GameRes.Formats.DirectDraw
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;
@ -56,14 +68,60 @@ namespace GameRes.Formats.DirectDraw
return m_output;
}
byte[] m_dxt5_alpha = new byte[16];
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_dxt5_alpha);
DecompressDXT5Alpha (input, src+2, m_dxt_buffer);
ushort color0 = LittleEndian.ToUInt16 (input, src+8);
ushort color1 = LittleEndian.ToUInt16 (input, src+10);
@ -87,7 +145,7 @@ namespace GameRes.Formats.DirectDraw
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_dxt5_alpha[4 * y + x];
int alpha_code = m_dxt_buffer[4 * y + x];
byte alpha;
if (0 == alpha_code)
alpha = alpha0;