mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-14 13:50:13 +00:00
390 lines
10 KiB
C++
390 lines
10 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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// Based off ffmpeg's SMC decoder
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#include "video/codecs/smc.h"
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#include "common/stream.h"
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#include "common/textconsole.h"
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namespace Video {
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#define GET_BLOCK_COUNT() \
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(opcode & 0x10) ? (1 + stream->readByte()) : 1 + (opcode & 0x0F);
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#define ADVANCE_BLOCK() \
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{ \
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pixelPtr += 4; \
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if (pixelPtr >= _surface->w) { \
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pixelPtr = 0; \
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rowPtr += _surface->w * 4; \
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} \
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totalBlocks--; \
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if (totalBlocks < 0) { \
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warning("block counter just went negative (this should not happen)"); \
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return _surface; \
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} \
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}
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SMCDecoder::SMCDecoder(uint16 width, uint16 height) {
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_surface = new Graphics::Surface();
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_surface->create(width, height, Graphics::PixelFormat::createFormatCLUT8());
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}
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SMCDecoder::~SMCDecoder() {
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_surface->free();
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delete _surface;
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}
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const Graphics::Surface *SMCDecoder::decodeImage(Common::SeekableReadStream *stream) {
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byte *pixels = (byte *)_surface->pixels;
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uint32 numBlocks = 0;
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uint32 colorFlags = 0;
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uint32 colorFlagsA = 0;
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uint32 colorFlagsB = 0;
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const uint16 rowInc = _surface->w - 4;
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int32 rowPtr = 0;
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int32 pixelPtr = 0;
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uint32 blockPtr = 0;
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uint32 prevBlockPtr = 0;
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uint32 prevBlockPtr1 = 0, prevBlockPtr2 = 0;
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byte prevBlockFlag = false;
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uint32 pixel = 0;
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uint32 colorPairIndex = 0;
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uint32 colorQuadIndex = 0;
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uint32 colorOctetIndex = 0;
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uint32 colorTableIndex = 0; // indices to color pair, quad, or octet tables
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int32 chunkSize = stream->readUint32BE() & 0x00FFFFFF;
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if (chunkSize != stream->size())
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warning("MOV chunk size != SMC chunk size (%d != %d); ignoring SMC chunk size", chunkSize, stream->size());
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int32 totalBlocks = ((_surface->w + 3) / 4) * ((_surface->h + 3) / 4);
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// traverse through the blocks
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while (totalBlocks != 0) {
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// sanity checks
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// make sure stream ptr hasn't gone out of bounds
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if (stream->pos() > stream->size()) {
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warning("SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)", stream->pos(), stream->size());
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return _surface;
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}
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// make sure the row pointer hasn't gone wild
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if (rowPtr >= _surface->w * _surface->h) {
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warning("SMC decoder just went out of bounds (row ptr = %d, size = %d)", rowPtr, _surface->w * _surface->h);
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return _surface;
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}
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byte opcode = stream->readByte();
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switch (opcode & 0xF0) {
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// skip n blocks
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case 0x00:
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case 0x10:
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numBlocks = GET_BLOCK_COUNT();
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while (numBlocks--) {
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ADVANCE_BLOCK();
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}
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break;
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// repeat last block n times
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case 0x20:
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case 0x30:
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numBlocks = GET_BLOCK_COUNT();
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// sanity check
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if (rowPtr == 0 && pixelPtr == 0) {
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warning("encountered repeat block opcode (%02X) but no blocks rendered yet", opcode & 0xF0);
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break;
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}
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// figure out where the previous block started
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if (pixelPtr == 0)
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prevBlockPtr1 = (rowPtr - _surface->w * 4) + _surface->w - 4;
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else
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prevBlockPtr1 = rowPtr + pixelPtr - 4;
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while (numBlocks--) {
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blockPtr = rowPtr + pixelPtr;
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prevBlockPtr = prevBlockPtr1;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++)
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pixels[blockPtr++] = pixels[prevBlockPtr++];
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blockPtr += rowInc;
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prevBlockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// repeat previous pair of blocks n times
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case 0x40:
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case 0x50:
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numBlocks = GET_BLOCK_COUNT();
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numBlocks *= 2;
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// sanity check
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if (rowPtr == 0 && pixelPtr < 2 * 4) {
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warning("encountered repeat block opcode (%02X) but not enough blocks rendered yet", opcode & 0xF0);
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break;
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}
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// figure out where the previous 2 blocks started
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if (pixelPtr == 0)
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prevBlockPtr1 = (rowPtr - _surface->w * 4) + _surface->w - 4 * 2;
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else if (pixelPtr == 4)
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prevBlockPtr1 = (rowPtr - _surface->w * 4) + rowInc;
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else
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prevBlockPtr1 = rowPtr + pixelPtr - 4 * 2;
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if (pixelPtr == 0)
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prevBlockPtr2 = (rowPtr - _surface->w * 4) + rowInc;
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else
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prevBlockPtr2 = rowPtr + pixelPtr - 4;
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prevBlockFlag = 0;
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while (numBlocks--) {
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blockPtr = rowPtr + pixelPtr;
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if (prevBlockFlag)
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prevBlockPtr = prevBlockPtr2;
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else
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prevBlockPtr = prevBlockPtr1;
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prevBlockFlag = !prevBlockFlag;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++)
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pixels[blockPtr++] = pixels[prevBlockPtr++];
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blockPtr += rowInc;
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prevBlockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// 1-color block encoding
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case 0x60:
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case 0x70:
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numBlocks = GET_BLOCK_COUNT();
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pixel = stream->readByte();
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while (numBlocks--) {
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blockPtr = rowPtr + pixelPtr;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++)
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pixels[blockPtr++] = pixel;
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blockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// 2-color block encoding
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case 0x80:
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case 0x90:
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numBlocks = (opcode & 0x0F) + 1;
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// figure out which color pair to use to paint the 2-color block
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if ((opcode & 0xF0) == 0x80) {
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// fetch the next 2 colors from bytestream and store in next
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// available entry in the color pair table
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for (byte i = 0; i < CPAIR; i++) {
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pixel = stream->readByte();
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colorTableIndex = CPAIR * colorPairIndex + i;
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_colorPairs[colorTableIndex] = pixel;
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}
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// this is the base index to use for this block
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colorTableIndex = CPAIR * colorPairIndex;
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colorPairIndex++;
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// wraparound
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if (colorPairIndex == COLORS_PER_TABLE)
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colorPairIndex = 0;
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} else
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colorTableIndex = CPAIR * stream->readByte();
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while (numBlocks--) {
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colorFlags = stream->readUint16BE();
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uint16 flagMask = 0x8000;
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blockPtr = rowPtr + pixelPtr;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++) {
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if (colorFlags & flagMask)
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pixel = colorTableIndex + 1;
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else
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pixel = colorTableIndex;
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flagMask >>= 1;
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pixels[blockPtr++] = _colorPairs[pixel];
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}
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blockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// 4-color block encoding
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case 0xA0:
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case 0xB0:
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numBlocks = (opcode & 0x0F) + 1;
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// figure out which color quad to use to paint the 4-color block
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if ((opcode & 0xF0) == 0xA0) {
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// fetch the next 4 colors from bytestream and store in next
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// available entry in the color quad table
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for (byte i = 0; i < CQUAD; i++) {
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pixel = stream->readByte();
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colorTableIndex = CQUAD * colorQuadIndex + i;
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_colorQuads[colorTableIndex] = pixel;
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}
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// this is the base index to use for this block
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colorTableIndex = CQUAD * colorQuadIndex;
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colorQuadIndex++;
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// wraparound
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if (colorQuadIndex == COLORS_PER_TABLE)
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colorQuadIndex = 0;
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} else
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colorTableIndex = CQUAD * stream->readByte();
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while (numBlocks--) {
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colorFlags = stream->readUint32BE();
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// flag mask actually acts as a bit shift count here
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byte flagMask = 30;
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blockPtr = rowPtr + pixelPtr;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++) {
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pixel = colorTableIndex + ((colorFlags >> flagMask) & 0x03);
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flagMask -= 2;
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pixels[blockPtr++] = _colorQuads[pixel];
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}
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blockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// 8-color block encoding
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case 0xC0:
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case 0xD0:
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numBlocks = (opcode & 0x0F) + 1;
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// figure out which color octet to use to paint the 8-color block
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if ((opcode & 0xF0) == 0xC0) {
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// fetch the next 8 colors from bytestream and store in next
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// available entry in the color octet table
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for (byte i = 0; i < COCTET; i++) {
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pixel = stream->readByte();
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colorTableIndex = COCTET * colorOctetIndex + i;
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_colorOctets[colorTableIndex] = pixel;
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}
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// this is the base index to use for this block
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colorTableIndex = COCTET * colorOctetIndex;
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colorOctetIndex++;
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// wraparound
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if (colorOctetIndex == COLORS_PER_TABLE)
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colorOctetIndex = 0;
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} else
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colorTableIndex = COCTET * stream->readByte();
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while (numBlocks--) {
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/*
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For this input of 6 hex bytes:
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01 23 45 67 89 AB
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Mangle it to this output:
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flags_a = xx012456, flags_b = xx89A37B
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*/
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// build the color flags
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byte flagData[6];
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stream->read(flagData, 6);
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colorFlagsA = ((READ_BE_UINT16(flagData) & 0xFFF0) << 8) | (READ_BE_UINT16(flagData + 2) >> 4);
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colorFlagsB = ((READ_BE_UINT16(flagData + 4) & 0xFFF0) << 8) | ((flagData[1] & 0xF) << 8) |
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((flagData[3] & 0xF) << 4) | (flagData[5] & 0xf);
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colorFlags = colorFlagsA;
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// flag mask actually acts as a bit shift count here
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byte flagMask = 21;
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blockPtr = rowPtr + pixelPtr;
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for (byte y = 0; y < 4; y++) {
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// reload flags at third row (iteration y == 2)
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if (y == 2) {
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colorFlags = colorFlagsB;
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flagMask = 21;
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}
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for (byte x = 0; x < 4; x++) {
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pixel = colorTableIndex + ((colorFlags >> flagMask) & 0x07);
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flagMask -= 3;
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pixels[blockPtr++] = _colorOctets[pixel];
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}
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blockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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// 16-color block encoding (every pixel is a different color)
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case 0xE0:
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numBlocks = (opcode & 0x0F) + 1;
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while (numBlocks--) {
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blockPtr = rowPtr + pixelPtr;
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for (byte y = 0; y < 4; y++) {
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for (byte x = 0; x < 4; x++)
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pixels[blockPtr++] = stream->readByte();
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blockPtr += rowInc;
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}
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ADVANCE_BLOCK();
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}
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break;
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case 0xF0:
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warning("0xF0 opcode seen in SMC chunk (contact the developers)");
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break;
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}
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}
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return _surface;
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}
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} // End of namespace Video
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