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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 "ags/lib/allegro/fmaths.h"
namespace AGS3 {
fixed fixsqrt(fixed x) {
if (x > 0)
return ftofix(sqrt(fixtof(x)));
if (x < 0)
*allegro_errno = EDOM;
return 0;
}
fixed fixhypot(fixed x, fixed y) {
return ftofix(hypot(fixtof(x), fixtof(y)));
}
fixed fixatan(fixed x) {
int a, b, c; /* for binary search */
fixed d; /* difference value for search */
if (x >= 0) { /* search the first part of tan table */
a = 0;
b = 127;
} else { /* search the second half instead */
a = 128;
b = 255;
}
do {
c = (a + b) >> 1;
d = x - _tan_tbl[c];
if (d > 0)
a = c + 1;
else if (d < 0)
b = c - 1;
} while ((a <= b) && (d));
if (x >= 0)
return ((long)c) << 15;
return (-0x00800000L + (((long)c) << 15));
}
fixed fixatan2(fixed y, fixed x) {
fixed r;
if (x == 0) {
if (y == 0) {
*allegro_errno = EDOM;
return 0L;
} else
return ((y < 0) ? -0x00400000L : 0x00400000L);
}
*allegro_errno = 0;
r = fixdiv(y, x);
if (*allegro_errno) {
*allegro_errno = 0;
return ((y < 0) ? -0x00400000L : 0x00400000L);
}
r = fixatan(r);
if (x >= 0)
return r;
if (y >= 0)
return 0x00800000L + r;
return r - 0x00800000L;
}
} // namespace AGS3
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