Initial commit

engines/scumm/usage_bits.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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#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::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::testGfxObjectUsageBits(int strip) {
+	// Test whether any of the DIRTY or RESTORED bits is set
+	return testGfxUsageBit(strip, USAGE_BIT_DIRTY) || testGfxUsageBit(strip, USAGE_BIT_RESTORED);
+}
+
+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