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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 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.
*
*/
#include "startrek/startrek.h"
namespace StarTrek {
Fixed14 StarTrekEngine::sin(Angle angle) {
int16 i = angle.raw();
if (angle < 0) {
i %= 0x400;
i += 0x400;
}
i &= 0x3ff;
if (i == 0x100)
return 1.0;
else if (i == 0x300)
return -1.0;
float f = _sineTable.at(i);
return Fixed14(f);
}
Fixed14 StarTrekEngine::cos(Angle angle) {
return sin(angle + 1.0);
}
Angle StarTrekEngine::atan2(int32 deltaX, int32 deltaY) {
static const int16 atanTable[] = {
0x0000, 0x0064, 0x00c9, 0x012d, 0x0192, 0x01f6, 0x025b, 0x02c0,
0x0324, 0x0389, 0x03ee, 0x0453, 0x04b8, 0x051d, 0x0582, 0x05e8,
0x064d, 0x06b3, 0x0718, 0x077e, 0x07e4, 0x084a, 0x08b1, 0x0917,
0x097e, 0x09e5, 0x0a4c, 0x0ab3, 0x0b1a, 0x0b82, 0x0bea, 0x0c52,
0x0cba, 0x0d23, 0x0d8c, 0x0df5, 0x0e5f, 0x0ec8, 0x0f32, 0x0f9d,
0x1007, 0x1072, 0x10de, 0x114a, 0x11b6, 0x1222, 0x128f, 0x12fc,
0x136a, 0x13d8, 0x1446, 0x14b5, 0x1524, 0x1594, 0x1604, 0x1675,
0x16e6, 0x1757, 0x17ca, 0x183c, 0x18b0, 0x1923, 0x1998, 0x1a0c,
0x1a82, 0x1af8, 0x1b6f, 0x1be6, 0x1c5e, 0x1cd7, 0x1d50, 0x1dca,
0x1e45, 0x1ec0, 0x1f3c, 0x1fb9, 0x2037, 0x20b5, 0x2134, 0x21b4,
0x2235, 0x22b7, 0x2339, 0x23bd, 0x2441, 0x24c6, 0x254c, 0x25d4,
0x265c, 0x26e5, 0x276f, 0x27fa, 0x2887, 0x2914, 0x29a2, 0x2a32,
0x2ac3, 0x2b55, 0x2be8, 0x2c7d, 0x2d12, 0x2da9, 0x2e42, 0x2edc,
0x2f77, 0x3013, 0x30b1, 0x3151, 0x31f2, 0x3294, 0x3338, 0x33de,
0x3486, 0x352f, 0x35d9, 0x3686, 0x3734, 0x37e5, 0x3897, 0x394b,
0x3a01, 0x3ab9, 0x3b73, 0x3c30, 0x3cee, 0x3daf, 0x3e72, 0x3f38,
0x4000
};
if (deltaX == 0 && deltaY == 0)
return 0.0;
bool deltaYNegative = deltaY <= 0;
bool deltaXNegative = deltaX <= 0;
deltaY = abs(deltaY);
deltaX = abs(deltaX);
Fixed14 ratio;
if (deltaY > deltaX)
ratio = Fixed14::fromRaw(((deltaX & 0xffff0000) >> 2) / deltaY);
else
ratio = Fixed14::fromRaw(((deltaY & 0xffff0000) >> 2) / deltaX);
int16 endIndex = 128;
int16 index = 0;
int16 angle;
while (index <= endIndex) {
angle = (index + endIndex) / 2;
Fixed14 tableValue = Fixed14::fromRaw(atanTable[angle]);
if (tableValue > ratio)
endIndex = angle - 1;
else if (tableValue < ratio)
index = angle + 1;
else
break;
}
if (deltaY > deltaX) {
if (deltaYNegative && deltaXNegative)
angle = angle - 512;
else if (deltaYNegative && !deltaXNegative)
angle = 512 - angle;
else if (!deltaYNegative && deltaXNegative)
angle = -angle;
// else if (!deltaYNegative && !deltaXNegative)
// angle remains the same i.e. angle = angle
} else {
if (deltaYNegative && deltaXNegative)
angle = -256 - angle;
else if (deltaYNegative && !deltaXNegative)
angle = 256 + angle;
else if (!deltaYNegative && deltaXNegative)
angle = -256 + angle;
else // if (!deltaYNegative && !deltaXNegative)
angle = 256 - angle;
}
return Angle::fromRaw(angle);
}
} // End of namespace StarTrek
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