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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.
*
*/
// Based off ffmpeg's msvideo.cpp
#include "image/codecs/msvideo1.h"
#include "common/stream.h"
#include "common/textconsole.h"
namespace Image {
#define CHECK_STREAM_PTR(n) \
if ((stream.pos() + n) > stream.size() ) { \
warning ("MS Video-1: Stream out of bounds (%d >= %d) d%d", stream.pos() + n, stream.size(), n); \
return; \
}
MSVideo1Decoder::MSVideo1Decoder(uint16 width, uint16 height, byte bitsPerPixel) : Codec() {
_surface = new Graphics::Surface();
_surface->create(width, height, (bitsPerPixel == 8) ? Graphics::PixelFormat::createFormatCLUT8() :
Graphics::PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0));
_bitsPerPixel = bitsPerPixel;
}
MSVideo1Decoder::~MSVideo1Decoder() {
_surface->free();
delete _surface;
}
void MSVideo1Decoder::decode8(Common::SeekableReadStream &stream) {
byte colors[8];
byte *pixels = (byte *)_surface->getPixels();
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--;
}
}
}
void MSVideo1Decoder::decode16(Common::SeekableReadStream &stream) {
/* decoding parameters */
uint16 colors[8];
uint16 *pixels = (uint16 *)_surface->getPixels();
int32 stride = _surface->w;
int32 skip_blocks = 0;
int32 blocks_wide = _surface->w / 4;
int32 blocks_high = _surface->h / 4;
int32 total_blocks = blocks_wide * blocks_high;
int32 block_inc = 4;
int32 row_dec = stride + 4;
for (int32 block_y = blocks_high; block_y > 0; block_y--) {
int32 block_ptr = ((block_y * 4) - 1) * stride;
for (int32 block_x = blocks_wide; block_x > 0; block_x--) {
/* check if this block should be skipped */
if (skip_blocks) {
block_ptr += block_inc;
skip_blocks--;
total_blocks--;
continue;
}
int32 pixel_ptr = block_ptr;
/* 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) && (total_blocks == 0)) {
return;
} else if ((byte_b & 0xFC) == 0x84) {
/* skip code, but don't count the current block */
skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
} else if (byte_b < 0x80) {
/* 2- or 8-color encoding modes */
uint16 flags = (byte_b << 8) | byte_a;
CHECK_STREAM_PTR(4);
colors[0] = stream.readUint16LE();
colors[1] = stream.readUint16LE();
if (colors[0] & 0x8000) {
/* 8-color encoding */
CHECK_STREAM_PTR(12);
colors[2] = stream.readUint16LE();
colors[3] = stream.readUint16LE();
colors[4] = stream.readUint16LE();
colors[5] = stream.readUint16LE();
colors[6] = stream.readUint16LE();
colors[7] = stream.readUint16LE();
for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
for (int pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
pixels[pixel_ptr++] =
colors[((pixel_y & 0x2) << 1) +
(pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
pixel_ptr -= row_dec;
}
} else {
/* 2-color encoding */
for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
for (int pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
pixel_ptr -= row_dec;
}
}
} else {
/* otherwise, it's a 1-color block */
colors[0] = (byte_b << 8) | byte_a;
for (int pixel_y = 0; pixel_y < 4; pixel_y++) {
for (int pixel_x = 0; pixel_x < 4; pixel_x++)
pixels[pixel_ptr++] = colors[0];
pixel_ptr -= row_dec;
}
}
block_ptr += block_inc;
total_blocks--;
}
}
}
const Graphics::Surface *MSVideo1Decoder::decodeFrame(Common::SeekableReadStream &stream) {
if (_bitsPerPixel == 8)
decode8(stream);
else
decode16(stream);
return _surface;
}
} // End of namespace Image
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