mirror of
https://github.com/yuzu-emu/FasTC.git
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126 lines
4.5 KiB
C++
126 lines
4.5 KiB
C++
/* FasTC
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* Copyright (c) 2013 University of North Carolina at Chapel Hill.
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* All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for educational, research, and non-profit purposes, without
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* fee, and without a written agreement is hereby granted, provided that the
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* above copyright notice, this paragraph, and the following four paragraphs
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* appear in all copies.
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*
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* Permission to incorporate this software into commercial products may be
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* obtained by contacting the authors or the Office of Technology Development
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* at the University of North Carolina at Chapel Hill <otd@unc.edu>.
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*
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* This software program and documentation are copyrighted by the University of
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* North Carolina at Chapel Hill. The software program and documentation are
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* supplied "as is," without any accompanying services from the University of
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* North Carolina at Chapel Hill or the authors. The University of North
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* Carolina at Chapel Hill and the authors do not warrant that the operation of
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* the program will be uninterrupted or error-free. The end-user understands
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* that the program was developed for research purposes and is advised not to
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* rely exclusively on the program for any reason.
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*
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* IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE
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* AUTHORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
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* OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
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* THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA
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* AT CHAPEL HILL OR THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY
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* DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY
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* STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON
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* AN "AS IS" BASIS, AND THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND
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* THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
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* ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Please send all BUG REPORTS to <pavel@cs.unc.edu>.
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*
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* The authors may be contacted via:
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*
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* Pavel Krajcevski
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* Dept of Computer Science
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* 201 S Columbia St
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* Frederick P. Brooks, Jr. Computer Science Bldg
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* Chapel Hill, NC 27599-3175
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* USA
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*
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* <http://gamma.cs.unc.edu/FasTC/>
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*/
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#include "FasTC/DXTCompressor.h"
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#include <cassert>
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#include <cstdlib>
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#include <cstring>
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#include "FasTC/Pixel.h"
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namespace DXTC
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{
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void DecompressDXT1Block(const uint8 *block, uint32 *outBuf) {
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// When we call FasTC::Pixel::FromBits, we expect the bits
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// to be read out of memory in LSB (byte) order first. Hence,
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// we can't read the blocks directly as uint16 values out of
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// the DXT buffer and we have to swap the bytes before hand.
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uint16 colorA = block[0];
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colorA <<= 8;
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colorA |= block[1];
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uint16 colorB = block[2];
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colorB <<= 8;
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colorB |= block[3];
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uint32 mod = reinterpret_cast<const uint32 *>(block + 4)[0];
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uint8 kFiveSixFive[4] = { 0, 5, 6, 5 };
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FasTC::Pixel a, b, c, d;
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a.FromBits(reinterpret_cast<const uint8 *>(&colorA), kFiveSixFive);
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b.FromBits(reinterpret_cast<const uint8 *>(&colorB), kFiveSixFive);
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uint8 kFullDepth[4] = {8, 8, 8, 8};
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a.ChangeBitDepth(kFullDepth);
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b.ChangeBitDepth(kFullDepth);
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d = (a + b*2) / 3;
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c = (a*2 + b) / 3;
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FasTC::Pixel *colors[4] = { &a, &b, &c, &d };
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uint32 *outPixels = reinterpret_cast<uint32 *>(outBuf);
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for(uint32 i = 0; i < 16; i++) {
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outPixels[i] = colors[(mod >> (i*2)) & 3]->Pack();
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}
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}
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void DecompressDXT1(const FasTC::DecompressionJob &dcj)
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{
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assert(!(dcj.Height() & 3));
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assert(!(dcj.Width() & 3));
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uint32 blockW = dcj.Width() >> 2;
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uint32 blockH = dcj.Height() >> 2;
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const uint32 blockSz = GetBlockSize(FasTC::eCompressionFormat_DXT1);
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uint32 *outPixels = reinterpret_cast<uint32 *>(dcj.OutBuf());
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uint32 outBlock[16];
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for(uint32 j = 0; j < blockH; j++) {
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for(uint32 i = 0; i < blockW; i++) {
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uint32 offset = (j * blockW + i) * blockSz;
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DecompressDXT1Block(dcj.InBuf() + offset, outBlock);
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for(uint32 y = 0; y < 4; y++)
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for(uint32 x = 0; x < 4; x++) {
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offset = (j*4 + y)*dcj.Width() + ((i*4)+x);
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outPixels[offset] = outBlock[y*4 + x];
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}
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}
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}
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}
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}
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