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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
// Based off ffmpeg's msvideo.cpp
#include "graphics/video/msvideo1.h"
namespace Graphics {
#define CHECK_STREAM_PTR(n) \
if ((stream->pos() + n) > stream->size() ) { \
warning ("MS Video-1: Stream out of bounds (%d >= %d)", stream->pos() + n, stream->size()); \
return; \
}
MSVideo1Decoder::MSVideo1Decoder(uint16 width, uint16 height, byte bitsPerPixel) : Codec() {
_surface = new Graphics::Surface();
_surface->create(width, height, (bitsPerPixel == 8) ? 1 : 2);
_bitsPerPixel = bitsPerPixel;
}
MSVideo1Decoder::~MSVideo1Decoder() {
_surface->free();
delete _surface;
}
void MSVideo1Decoder::decode8(Common::SeekableReadStream *stream) {
byte colors[8];
byte *pixels = (byte *)_surface->pixels;
uint16 stride = _surface->w;
int skipBlocks = 0;
uint16 blocks_wide = _surface->w / 4;
uint16 blocks_high = _surface->h / 4;
uint32 totalBlocks = blocks_wide * blocks_high;
uint32 blockInc = 4;
uint16 rowDec = stride + 4;
for (uint16 block_y = blocks_high; block_y > 0; block_y--) {
uint32 blockPtr = (block_y * 4 - 1) * stride;
for (uint16 block_x = blocks_wide; block_x > 0; block_x--) {
// check if this block should be skipped
if (skipBlocks > 0) {
blockPtr += blockInc;
skipBlocks--;
totalBlocks--;
continue;
}
uint32 pixelPtr = blockPtr;
/* get the next two bytes in the encoded data stream */
CHECK_STREAM_PTR(2);
byte byte_a = stream->readByte();
byte byte_b = stream->readByte();
/* check if the decode is finished */
if (byte_a == 0 && byte_b == 0 && totalBlocks == 0) {
return;
} else if ((byte_b & 0xFC) == 0x84) {
// skip code, but don't count the current block
skipBlocks = ((byte_b - 0x84) << 8) + byte_a - 1;
} else if (byte_b < 0x80) {
// 2-color encoding
uint16 flags = (byte_b << 8) | byte_a;
CHECK_STREAM_PTR(2);
colors[0] = stream->readByte();
colors[1] = stream->readByte();
for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
for (byte pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
pixels[pixelPtr++] = colors[(flags & 0x1) ^ 1];
pixelPtr -= rowDec;
}
} else if (byte_b >= 0x90) {
// 8-color encoding
uint16 flags = (byte_b << 8) | byte_a;
CHECK_STREAM_PTR(8);
for (byte i = 0; i < 8; i++)
colors[i] = stream->readByte();
for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
for (byte pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
pixels[pixelPtr++] = colors[((pixel_y & 0x2) << 1) + (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
pixelPtr -= rowDec;
}
} else {
// 1-color encoding
colors[0] = byte_a;
for (byte pixel_y = 0; pixel_y < 4; pixel_y++) {
for (byte pixel_x = 0; pixel_x < 4; pixel_x++)
pixels[pixelPtr++] = colors[0];
pixelPtr -= rowDec;
}
}
blockPtr += blockInc;
totalBlocks--;
}
}
}
Graphics::Surface *MSVideo1Decoder::decodeImage(Common::SeekableReadStream *stream) {
if (_bitsPerPixel == 8)
decode8(stream);
else {
// decode16(stream);
error ("Unhandled MS Video-1 16bpp encoding");
}
return _surface;
}
} // End of namespace JMP
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