raze-gles/source/common/thirdparty/math/fastsin.cpp

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/*
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** fastsin.cpp
** a table/linear interpolation-based sine function that is both
** precise and fast enough for most purposes.
**
**---------------------------------------------------------------------------
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** Copyright 2015 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
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#include <math.h>
#include "cmath.h"
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#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
FFastTrig fasttrig;
FFastTrig::FFastTrig()
{
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const double pimul = M_PI * 2 / TBLPERIOD;
for (int i = 0; i < 2049; i++)
{
sinetable[i] = (float)c_sin(i*pimul);
}
}
__forceinline double FFastTrig::sinq1(unsigned bangle)
{
unsigned int index = bangle >> BITSHIFT;
if ((bangle &= (REMAINDER)) == 0) // This is to avoid precision problems at 180<38>
{
return double(sinetable[index]);
}
else
{
return (double(sinetable[index]) * (REMAINDER - bangle) + double(sinetable[index + 1]) * bangle) * (1. / REMAINDER);
}
}
double FFastTrig::sin(unsigned bangle)
{
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switch (bangle & 0xc0000000)
{
default:
return sinq1(bangle);
case 0x40000000:
return sinq1(0x80000000 - bangle);
case 0x80000000:
return -sinq1(bangle - 0x80000000);
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case 0xc0000000:
return -sinq1(0 - bangle);
}
}
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double FFastTrig::cos(unsigned bangle)
{
switch (bangle & 0xc0000000)
{
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default:
return sinq1(0x40000000 - bangle);
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case 0x40000000:
return -sinq1(bangle - 0x40000000);
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case 0x80000000:
return -sinq1(0xc0000000 - bangle);
case 0xc0000000:
return sinq1(bangle - 0xc0000000);
}
}