aboutsummaryrefslogtreecommitdiff
path: root/engines/sci/engine/kmath.cpp
blob: ea427435f2612f742c3cc396143d31940b27c694 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
/* 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 "sci/engine/state.h"
#include "sci/engine/kernel.h"

namespace Sci {

reg_t kRandom(EngineState *s, int argc, reg_t *argv) {
	return make_reg(0, argv[0].toSint16() + (int)((argv[1].toSint16() + 1.0 - argv[0].toSint16()) * (rand() / (RAND_MAX + 1.0))));
}

reg_t kAbs(EngineState *s, int argc, reg_t *argv) {
	// This is a hack, but so is the code in Hoyle1 that needs it.
	if (argv[0].segment)
		return make_reg(0, 0x3e8); // Yes people, this is an object
	return make_reg(0, abs(argv[0].toSint16()));
}

reg_t kSqrt(EngineState *s, int argc, reg_t *argv) {
	return make_reg(0, (int16) sqrt((float) abs(argv[0].toSint16())));
}

int get_angle(int xrel, int yrel) {
	if ((xrel == 0) && (yrel == 0))
		return 0;
	else {
		int val = (int)(180.0 / PI * atan2((double)xrel, (double) - yrel));
		if (val < 0)
			val += 360;

		// Take care of OB1 differences between SSCI and
		// FSCI. SCI games sometimes check for equality with
		// "round" angles
		if (val % 45 == 44)
			val++;
		else if (val % 45 == 1)
			val--;

		return val;
	}
}

reg_t kGetAngle(EngineState *s, int argc, reg_t *argv) {
	// Based on behavior observed with a test program created with
	// SCI Studio.
	int x1 = argv[0].toSint16();
	int y1 = argv[1].toSint16();
	int x2 = argv[2].toSint16();
	int y2 = argv[3].toSint16();
	int xrel = x2 - x1;
	int yrel = y1 - y2; // y-axis is mirrored.
	int angle;

	// Move (xrel, yrel) to first quadrant.
	if (y1 < y2)
		yrel = -yrel;
	if (x2 < x1)
		xrel = -xrel;

	// Compute angle in grads.
	if (yrel == 0 && xrel == 0)
		angle = 0;
	else
		angle = 100 * xrel / (xrel + yrel);

	// Fix up angle for actual quadrant of (xrel, yrel).
	if (y1 < y2)
		angle = 200 - angle;
	if (x2 < x1)
		angle = 400 - angle;

	// Convert from grads to degrees by merging grad 0 with grad 1,
	// grad 10 with grad 11, grad 20 with grad 21, etc. This leads to
	// "degrees" that equal either one or two grads.
	angle -= (angle + 9) / 10;

	return make_reg(0, angle);
}

reg_t kGetDistance(EngineState *s, int argc, reg_t *argv) {
	int xdiff = (argc > 3) ? argv[3].toSint16() : 0;
	int ydiff = (argc > 2) ? argv[2].toSint16() : 0;
	int angle = (argc > 5) ? argv[5].toSint16() : 0;
	int xrel = (int)(((float) argv[1].toSint16() - xdiff) / cos(angle * PI / 180.0)); // This works because cos(0)==1
	int yrel = argv[0].toSint16() - ydiff;
	return make_reg(0, (int16)sqrt((float) xrel*xrel + yrel*yrel));
}

reg_t kTimesSin(EngineState *s, int argc, reg_t *argv) {
	int angle = argv[0].toSint16();
	int factor = argv[1].toSint16();

	return make_reg(0, (int)(factor * sin(angle * PI / 180.0)));
}

reg_t kTimesCos(EngineState *s, int argc, reg_t *argv) {
	int angle = argv[0].toSint16();
	int factor = argv[1].toSint16();

	return make_reg(0, (int)(factor * cos(angle * PI / 180.0)));
}

reg_t kCosDiv(EngineState *s, int argc, reg_t *argv) {
	int angle = argv[0].toSint16();
	int value = argv[1].toSint16();
	double cosval = cos(angle * PI / 180.0);

	if ((cosval < 0.0001) && (cosval > -0.0001)) {
		warning("kCosDiv: Attempted division by zero");
		return SIGNAL_REG;
	} else
		return make_reg(0, (int16)(value / cosval));
}

reg_t kSinDiv(EngineState *s, int argc, reg_t *argv) {
	int angle = argv[0].toSint16();
	int value = argv[1].toSint16();
	double sinval = sin(angle * PI / 180.0);

	if ((sinval < 0.0001) && (sinval > -0.0001)) {
		warning("kSinDiv: Attempted division by zero");
		return SIGNAL_REG;
	} else
		return make_reg(0, (int16)(value / sinval));
}

reg_t kTimesTan(EngineState *s, int argc, reg_t *argv) {
	int param = argv[0].toSint16();
	int scale = (argc > 1) ? argv[1].toSint16() : 1;

	param -= 90;
	if ((param % 90) == 0) {
		warning("kTimesTan: Attempted tan(pi/2)");
		return SIGNAL_REG;
	} else
		return make_reg(0, (int16) - (tan(param * PI / 180.0) * scale));
}

reg_t kTimesCot(EngineState *s, int argc, reg_t *argv) {
	int param = argv[0].toSint16();
	int scale = (argc > 1) ? argv[1].toSint16() : 1;

	if ((param % 90) == 0) {
		warning("kTimesCot: Attempted tan(pi/2)");
		return SIGNAL_REG;
	} else
		return make_reg(0, (int16)(tan(param * PI / 180.0) * scale));
}

} // End of namespace Sci