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bg.cpp
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bg.cpp
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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.
*
* $URL$
* $Id$
*
*/
#include "engines/express/bg.h"
#include "engines/express/debug.h"
#include "common/debug.h"
#include "common/system.h"
// Based on the Xentax Wiki documentation:
// http://wiki.xentax.com/index.php/The_Last_Express_BG
namespace Express {
BackGround::BackGround(Common::SeekableReadStream *in) : _data(NULL) {
load(in);
}
BackGround::~BackGround() {
reset();
}
void BackGround::show(void) {
g_system->fillScreen(0);
g_system->copyRectToScreen((byte *)_data, _width * 2, _posX, _posY, _width, _height);
g_system->updateScreen();
}
void BackGround::reset(void) {
delete[] _data;
_data = NULL;
}
bool BackGround::load(Common::SeekableReadStream *in) {
// Position on screen
_posX = in->readUint32LE();
_posY = in->readUint32LE();
// Size of the image
_width = in->readUint32LE();
_height = in->readUint32LE();
uint32 numPix = _width * _height;
debugC(10, kExpressDebugData | kExpressDebugAll, "Express::BackGround: pos=(%d,%d) size=(%d,%d)", _posX, _posY, _width, _height);
// Size of the components
uint32 sizeR = in->readUint32LE();
uint32 sizeB = in->readUint32LE();
uint32 sizeG = in->readUint32LE();
debugC(15, kExpressDebugData | kExpressDebugAll, "Express::BackGround: size of the components: (R,G,B)=(%d,%d,%d)", sizeR, sizeG, sizeB);
// Read the red component
byte *dataR = decodeComponent(in, sizeR, numPix);
bool ok = true;
if (!dataR) ok = false;
// Read the blue component
byte *dataB = NULL;
if (ok) {
dataB = decodeComponent(in, sizeB, numPix);
if (!dataB) ok = false;
}
// Read the green component
byte *dataG = NULL;
if (ok) {
dataG = decodeComponent(in, sizeG, numPix);
if (!dataG) ok = false;
}
// Merge the components
reset();
if (ok) {
_data = new uint16[numPix];
if (!_data) {
ok = false;
} else {
for (uint i = 0; i < numPix; i++) {
_data[i] = (dataR[i] << 10) + (dataG[i] << 5) + dataB[i];
}
}
}
// Free the temporary components
delete[] dataR;
delete[] dataG;
delete[] dataB;
return ok;
}
byte *BackGround::decodeComponent(Common::SeekableReadStream *in, uint32 inSize, uint32 outSize) {
// Create the destination array
byte *out = new byte[outSize];
if (!out)
return false;
// Initialize the decoding
uint32 inPos = 0;
uint32 outPos = 0;
// Decode
while (inPos < inSize) {
byte inByte = in->readByte();
inPos++;
if (inByte < 0x80) {
// Direct decompression (RLE)
byte len = (inByte >> 5) + 1;
byte data = inByte & 0x1f;
for (int i = 0; i < len && outPos < outSize; i++)
out[outPos++] = data;
} else {
// Buffer back reference, 4096 byte window
// Take inByte and the following value as a big endian
// OfsLen while zeroing the first bit
uint16 ofsLen = ((inByte & 0x7F) << 8) | in->readByte();
inPos++;
int32 len = (ofsLen >> 12) + 3;
int32 hisPos = outPos + (ofsLen & 0x0FFF) - 4096;
for (int i = 0; i < len && outPos < outSize; i++)
out[outPos++] = out[hisPos++];
}
}
return out;
}
} // End of Express namespace