scummvm/engines/scumm/usage_bits.cpp
2011-05-12 01:16:22 +02:00

96 lines
2.8 KiB
C++

/* 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.
*
*/
#include "scumm/scumm.h"
#include "scumm/usage_bits.h"
namespace Scumm {
void ScummEngine::upgradeGfxUsageBits() {
int i;
for (i = 409; i >= 0; i--) {
bool dirty_bit = ((gfxUsageBits[i] & 0x80000000) != 0);
bool restored_bit = ((gfxUsageBits[i] & 0x40000000) != 0);
gfxUsageBits[3 * i] = gfxUsageBits[i] & 0x3FFFFFFF;
if (dirty_bit)
setGfxUsageBit(i, USAGE_BIT_DIRTY);
if (restored_bit)
setGfxUsageBit(i, USAGE_BIT_RESTORED);
}
}
void ScummEngine::setGfxUsageBit(int strip, int bit) {
assert(strip >= 0 && strip < ARRAYSIZE(gfxUsageBits) / 3);
assert(1 <= bit && bit <= 96);
bit--;
gfxUsageBits[3 * strip + bit / 32] |= (1 << (bit % 32));
}
void ScummEngine::clearGfxUsageBit(int strip, int bit) {
assert(strip >= 0 && strip < ARRAYSIZE(gfxUsageBits) / 3);
assert(1 <= bit && bit <= 96);
bit--;
gfxUsageBits[3 * strip + bit / 32] &= ~(1 << (bit % 32));
}
bool ScummEngine::testGfxUsageBit(int strip, int bit) {
assert(strip >= 0 && strip < ARRAYSIZE(gfxUsageBits) / 3);
assert(1 <= bit && bit <= 96);
bit--;
return (gfxUsageBits[3 * strip + bit / 32] & (1 << (bit % 32))) != 0;
}
bool ScummEngine::testGfxAnyUsageBits(int strip) {
// Exclude the DIRTY and RESTORED bits from the test
uint32 bitmask[3] = { 0xFFFFFFFF, 0xFFFFFFFF, 0x3FFFFFFF };
int i;
assert(strip >= 0 && strip < ARRAYSIZE(gfxUsageBits) / 3);
for (i = 0; i < 3; i++)
if (gfxUsageBits[3 * strip + i] & bitmask[i])
return true;
return false;
}
bool ScummEngine::testGfxOtherUsageBits(int strip, int bit) {
// Don't exclude the DIRTY and RESTORED bits from the test
uint32 bitmask[3] = { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
int i;
assert(strip >= 0 && strip < ARRAYSIZE(gfxUsageBits) / 3);
assert(1 <= bit && bit <= 96);
bit--;
bitmask[bit / 32] &= ~(1 << (bit % 32));
for (i = 0; i < 3; i++)
if (gfxUsageBits[3 * strip + i] & bitmask[i])
return true;
return false;
}
} // End of namespace Scumm