UltimateZoneBuilder/Source/Native/fasttrig.h
Magnus Norddahl 4274ee2893 Use C++ and SSE code to do matrix math
Avoid copying by passing matrices by reference to RenderDevice
Use fasttrig from GZDoom for faster cos/sin
Don't set matrices unless they changed. Even though the memcmp prevents it from being pushed to OpenGL it is still a waste.
2019-12-19 03:12:44 +01:00

140 lines
3.7 KiB
C++

/*
** fastsin.h
** 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.
**---------------------------------------------------------------------------
**
*/
#pragma once
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
// This uses a sine table with linear interpolation
// For in-game calculations this is precise enough
// and this code is more than 10x faster than the
// Cephes sin and cos function.
struct FFastTrig
{
static const int TBLPERIOD = 8192;
static const int BITSHIFT = 19;
static const int REMAINDER = (1 << BITSHIFT) - 1;
float sinetable[2049];
__forceinline double sinq1(uint32_t bangle)
{
unsigned int index = bangle >> BITSHIFT;
if ((bangle &= (REMAINDER)) == 0) // This is to avoid precision problems at 180 degrees
{
return double(sinetable[index]);
}
else
{
return (double(sinetable[index]) * (REMAINDER - bangle) + double(sinetable[index + 1]) * bangle) * (1. / REMAINDER);
}
}
public:
FFastTrig()
{
const double pimul = M_PI * 2 / TBLPERIOD;
for (int i = 0; i < 2049; i++)
{
sinetable[i] = (float)std::sin(i * pimul);
}
}
double sin(uint32_t 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 cos(uint32_t 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);
}
}
};
static FFastTrig fasttrig;
// This must use xs_Float to guarantee proper integer wraparound.
#define DEG2BAM(f) ((uint32_t)std::round((f) * (0x40000000/90.)))
#define RAD2BAM(f) ((uint32_t)std::round((f) * (0x80000000/3.14159265358979323846)))
inline double fastcosdeg(double v)
{
return fasttrig.cos(DEG2BAM(v));
}
inline double fastsindeg(double v)
{
return fasttrig.sin(DEG2BAM(v));
}
inline double fastcos(double v)
{
return fasttrig.cos(RAD2BAM(v));
}
inline double fastsin(double v)
{
return fasttrig.sin(RAD2BAM(v));
}