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engines/icb/shake.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.
+ *
+ * Additional copyright for this file:
+ * Copyright (C) 1999-2000 Revolution Software Ltd.
+ * This code is based on source code created by Revolution Software,
+ * used with permission.
+ *
+ * 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 "engines/icb/common/px_common.h"
+#include "engines/icb/icb.h"
+#include "engines/icb/debug.h"
+#include "engines/icb/shake.h"
+#include "engines/icb/fn_routines.h"
+
+namespace ICB {
+
+#define MAX_SHAKE_LOOP (1000)
+
+int32 shakeX = 0;
+int32 shakeY = 0;
+
+int32 nextShakeX = 0;
+int32 nextShakeY = 0;
+
+int32 rangeX = 0;
+int32 rangeY = 0;
+
+int32 GetShakeX() { return shakeX; }
+
+int32 GetShakeY() {
+	return (shakeY << 1);
+}
+
+int32 GetNextShakeX() { return nextShakeX; }
+
+int32 GetNextShakeY() {
+	return nextShakeY << 1;
+}
+
+mcodeFunctionReturnCodes fn_set_screen_offset(int32 &, int32 *params) {
+	int32 x, y;
+
+	x = params[0];
+	y = params[1];
+
+	shakeX = nextShakeX = x;
+	shakeY = nextShakeY = y;
+
+	return IR_CONT;
+}
+
+// fn_shake_screen(cycles,rx,ry,sx,sy);
+mcodeFunctionReturnCodes fn_shake_screen(int32 &, int32 *params) {
+	int32 sx, sy;
+
+	static int32 cycles = 0;
+	static bool8 shaking = FALSE8;
+
+	// these are okay...
+	rangeX = params[1];
+	rangeY = params[2];
+
+	if (rangeX > GET_SHAKE_RANGE_MAX_X)
+		rangeX = GET_SHAKE_RANGE_MAX_X;
+	if (rangeY > GET_SHAKE_RANGE_MAX_Y)
+		rangeY = GET_SHAKE_RANGE_MAX_Y;
+
+	sx = params[3];
+	sy = params[4];
+
+	if (sx > (2 * GET_SHAKE_RANGE_MAX_X))
+		sx = 2 * GET_SHAKE_RANGE_MAX_X;
+	if (sy > (2 * GET_SHAKE_RANGE_MAX_Y))
+		sy = 2 * GET_SHAKE_RANGE_MAX_Y;
+
+	// if not shaking then set up the shake...
+	if (!shaking) {
+		shaking = TRUE8;
+		cycles = params[0];
+		if (cycles < 0)
+			Fatal_error("cycles < 0 in fn_shake_screen???");
+	}
+
+	// set actual shake to next shake...
+	shakeX = nextShakeX;
+	shakeY = nextShakeY;
+
+	// if we have some cycles to go then shake and return IR_RPEAT
+	if (cycles > 0) {
+		int32 rx = rangeX;
+		int32 ry = rangeY;
+
+		// one less cycle to go...
+		cycles--;
+
+		int32 randX, randY;
+		int32 x, y;
+
+		// Check that the current screen shake position is acceptable within the new shake range
+		if (((shakeX + sx) < -rx) || ((shakeX - sx) > rx)) {
+			shakeX = 0;
+		}
+		if (((shakeY + sy) < -ry) || ((shakeY - sy) > ry)) {
+			shakeY = 0;
+		}
+
+		// keep going till we find something that is acceptable...
+		int32 loop = 0;
+		// Want to make: -sx, -sx+1, .... 0, 1, 2, sx-1, sx
+		int32 sxrange = 2 * sx + 1;
+		// Want to make: -sy, -sy+1, .... 0, 1, 2, sy-1, sy
+		int32 syrange = 2 * sy + 1;
+		do {
+			// work out steps...
+			randX = (g_icb->getRandomSource()->getRandomNumber(sxrange - 1)) - sx;
+			randY = (g_icb->getRandomSource()->getRandomNumber(syrange - 1)) - sy;
+
+			x = shakeX + randX;
+			y = shakeY + randY;
+			loop++;
+			if (loop > MAX_SHAKE_LOOP)
+				break;
+		} while ((x > rx) || (x < -rx) || (y > ry) || (y < -ry));
+
+		if (loop > MAX_SHAKE_LOOP) {
+			x = shakeX;
+			y = shakeY;
+		}
+
+		// set the next lot to be this new value then...
+		nextShakeX = x;
+		nextShakeY = y;
+
+		return IR_REPEAT;
+	}
+
+	// otherwise we have finished so set shaking to zero, zero the shake and quit
+	nextShakeX = 0;
+	nextShakeY = 0;
+
+	if ((nextShakeX != shakeX) || (nextShakeY != shakeY))
+		return IR_REPEAT;
+
+	shaking = FALSE8;
+	return IR_CONT;
+}
+
+} // End of namespace ICB