100 lines
2.1 KiB
C++
100 lines
2.1 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "ags/lib/allegro/fmaths.h"
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namespace AGS3 {
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fixed fixsqrt(fixed x) {
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if (x > 0)
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return ftofix(sqrt(fixtof(x)));
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if (x < 0)
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*allegro_errno = EDOM;
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return 0;
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}
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fixed fixhypot(fixed x, fixed y) {
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return ftofix(hypot(fixtof(x), fixtof(y)));
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}
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fixed fixatan(fixed x) {
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int a, b, c; /* for binary search */
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fixed d; /* difference value for search */
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if (x >= 0) { /* search the first part of tan table */
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a = 0;
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b = 127;
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} else { /* search the second half instead */
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a = 128;
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b = 255;
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}
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do {
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c = (a + b) >> 1;
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d = x - _tan_tbl[c];
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if (d > 0)
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a = c + 1;
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else if (d < 0)
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b = c - 1;
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} while ((a <= b) && (d));
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if (x >= 0)
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return ((long)c) << 15;
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return (-0x00800000L + (((long)c) << 15));
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}
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fixed fixatan2(fixed y, fixed x) {
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fixed r;
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if (x == 0) {
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if (y == 0) {
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*allegro_errno = EDOM;
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return 0L;
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} else
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return ((y < 0) ? -0x00400000L : 0x00400000L);
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}
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*allegro_errno = 0;
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r = fixdiv(y, x);
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if (*allegro_errno) {
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*allegro_errno = 0;
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return ((y < 0) ? -0x00400000L : 0x00400000L);
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}
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r = fixatan(r);
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if (x >= 0)
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return r;
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if (y >= 0)
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return 0x00800000L + r;
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return r - 0x00800000L;
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}
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} // namespace AGS3
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