mirror of
https://github.com/ZDoom/gzdoom-gles.git
synced 2024-12-16 07:10:53 +00:00
103 lines
2.9 KiB
C++
103 lines
2.9 KiB
C++
|
/*
|
|||
|
|
** fastsin.cpp
|
|||
|
|
** a table/linear interpolation-based sine function that is both
|
|||
|
|
** precise and fast enough for most purposes.
|
|||
|
|
**
|
|||
|
|
**---------------------------------------------------------------------------
|
|||
|
|
** 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.
|
|||
|
|
**---------------------------------------------------------------------------
|
|||
|
|
**
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
#include <math.h>
|
|||
|
|
#include "cmath.h"
|
|||
|
|
#include "m_fixed.h"
|
|||
|
|
|
|||
|
|
FFastTrig fasttrig;
|
|||
|
|
|
|||
|
|
FFastTrig::FFastTrig()
|
|||
|
|
{
|
|||
|
|
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 - 1)) == 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)
|
|||
|
|
{
|
|||
|
|
switch (bangle & 0xc0000000)
|
|||
|
|
{
|
|||
|
|
default:
|
|||
|
|
return sinq1(bangle);
|
|||
|
|
|
|||
|
|
case 0x40000000:
|
|||
|
|
return sinq1(0x80000000 - bangle);
|
|||
|
|
|
|||
|
|
case 0x80000000:
|
|||
|
|
return -sinq1(bangle - 0x80000000);
|
|||
|
|
|
|||
|
|
case 0xc0000000:
|
|||
|
|
return -sinq1(0 - bangle);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
double FFastTrig::cos(unsigned bangle)
|
|||
|
|
{
|
|||
|
|
switch (bangle & 0xc0000000)
|
|||
|
|
{
|
|||
|
|
default:
|
|||
|
|
return sinq1(0x40000000 - bangle);
|
|||
|
|
|
|||
|
|
case 0x40000000:
|
|||
|
|
return -sinq1(bangle - 0x40000000);
|
|||
|
|
|
|||
|
|
case 0x80000000:
|
|||
|
|
return -sinq1(0xc0000000 - bangle);
|
|||
|
|
|
|||
|
|
case 0xc0000000:
|
|||
|
|
return sinq1(bangle - 0xc0000000);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|