mirror of
https://github.com/libretro/scummvm.git
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141 lines
3.3 KiB
C++
141 lines
3.3 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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*
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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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*
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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 msrledec.c
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#include "common/debug.h"
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#include "image/codecs/msrle4.h"
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#include "common/stream.h"
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#include "common/textconsole.h"
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#include "common/util.h"
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namespace Image {
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MSRLE4Decoder::MSRLE4Decoder(uint16 width, uint16 height, byte bitsPerPixel) {
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_surface = new Graphics::Surface();
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_surface->create(width, height, Graphics::PixelFormat::createFormatCLUT8());
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_bitsPerPixel = bitsPerPixel;
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}
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MSRLE4Decoder::~MSRLE4Decoder() {
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_surface->free();
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delete _surface;
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}
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const Graphics::Surface *MSRLE4Decoder::decodeFrame(Common::SeekableReadStream &stream) {
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if (_bitsPerPixel == 4) {
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decode4(stream);
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} else
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error("Unhandled %d bit Microsoft RLE encoding", _bitsPerPixel);
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return _surface;
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}
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void MSRLE4Decoder::decode4(Common::SeekableReadStream &stream) {
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int x = 0;
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int y = _surface->h - 1;
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byte *output = (byte *)_surface->getBasePtr(x, y);
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byte *output_end = (byte *)_surface->getBasePtr(_surface->w, y);
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while (!stream.eos()) {
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byte count = stream.readByte();
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if (count == 0) {
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byte value = stream.readByte();
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if (value == 0) {
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// End of line
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x = 0;
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y--;
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output = (byte *)_surface->getBasePtr(x, y);
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} else if (value == 1) {
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// End of image
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return;
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} else if (value == 2) {
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// Skip
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count = stream.readByte();
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value = stream.readByte();
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x += count;
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y -= value;
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if (y < 0) {
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warning("MS RLE Codec: Skip beyond picture bounds");
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return;
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}
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output = (byte *)_surface->getBasePtr(x, y);
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} else {
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// Copy data
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int odd_pixel = value & 1;
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int rle_code = (value + 1) / 2;
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int extra_byte = rle_code & 0x01;
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if (output + value > output_end) {
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stream.skip(rle_code + extra_byte);
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continue;
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}
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for (int i = 0; i < rle_code; i++) {
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byte color = stream.readByte();
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*output++ = (color & 0xf0) >> 4;
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if (i + 1 == rle_code && odd_pixel) {
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break;
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}
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*output++ = color & 0x0f;
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}
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if (extra_byte)
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stream.skip(1);
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x += value;
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}
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} else {
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// Run data
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if (output + count > output_end)
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continue;
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byte color = stream.readByte();
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for (int i = 0; i < count; i++, x++) {
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*output++ = (color & 0xf0) >> 4;
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i++;
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x++;
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if (i == count)
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break;
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*output++ = color & 0x0f;
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}
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}
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}
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warning("MS RLE Codec: No end-of-picture code");
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}
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} // End of namespace Image
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