mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-25 16:31:06 +00:00
121 lines
2.6 KiB
C++
121 lines
2.6 KiB
C++
/*
|
|
* \brief Table of sine and cosine values in 16.16 fractional format
|
|
* \author Norman Feske
|
|
* \date 2015-06-19
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2015-2017 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU Affero General Public License version 3.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__NANO3D__SINCOS_FRAC16_H_
|
|
#define _INCLUDE__NANO3D__SINCOS_FRAC16_H_
|
|
|
|
namespace Nano3d { class Sincos_frac16; };
|
|
|
|
|
|
class Nano3d::Sincos_frac16
|
|
{
|
|
public:
|
|
|
|
enum { STEPS = 1024 };
|
|
|
|
private:
|
|
|
|
int _table[STEPS + STEPS/4];
|
|
|
|
public:
|
|
|
|
inline Sincos_frac16();
|
|
|
|
int sin(int angle) const { return _table[angle & (STEPS - 1)]; }
|
|
int cos(int angle) const { return sin(angle + STEPS/4); }
|
|
};
|
|
|
|
|
|
Nano3d::Sincos_frac16::Sincos_frac16()
|
|
{
|
|
int const cos_mid = 0x7fff;
|
|
int const cos_low = 0x310b; /* cos(360/1024) = 0x7fff6216 */
|
|
int const sin_mid = 0x00c9;
|
|
int const sin_low = 0x07c4; /* sin(360/1024) = 0x00c90f87 */
|
|
|
|
int x_mid = 0x7fff;
|
|
int x_low = 0x7fff; /* x = 1.0 */
|
|
int y_mid = 0;
|
|
int y_low = 0; /* y = 0.0 */
|
|
|
|
int nx_high, ny_high;
|
|
int nx_mid, nx_low;
|
|
int ny_mid, ny_low;
|
|
|
|
for (unsigned i = 0; i < (STEPS >> 2); i++) {
|
|
|
|
/* store current sine value */
|
|
_table[i] = y_mid << 1;
|
|
_table[(STEPS >> 1) - i - 1] = y_mid << 1;
|
|
_table[i + (STEPS >> 1)] = -y_mid << 1;
|
|
_table[STEPS - i - 1] = -y_mid << 1;
|
|
|
|
/* rotate sin/cos values */
|
|
|
|
/* x' = x*cos - y*sin */
|
|
|
|
nx_low = x_low*cos_low
|
|
- y_low*sin_low;
|
|
|
|
nx_mid = x_low*cos_mid + x_mid*cos_low
|
|
- y_low*sin_mid - y_mid*sin_low;
|
|
nx_mid += (nx_low >> 14);
|
|
|
|
nx_high = x_mid*cos_mid
|
|
- y_mid*sin_mid
|
|
+ (nx_mid >> 15);
|
|
|
|
nx_high = nx_high << 1;
|
|
|
|
/* y' = y*cos + x*sin */
|
|
|
|
ny_low = y_low*cos_low
|
|
+ x_low*sin_low;
|
|
|
|
ny_mid = y_low*cos_mid + y_mid*cos_low
|
|
+ x_low*sin_mid + x_mid*sin_low
|
|
+ (ny_low >> 14);
|
|
|
|
ny_high = y_mid*cos_mid
|
|
+ x_mid*sin_mid
|
|
+ (ny_mid >> 15);
|
|
|
|
ny_high = ny_high << 1;
|
|
|
|
/* use new sin/cos values for next iteration, preserve sign */
|
|
x_low = (nx_high & 0x80000000) ? (nx_high | (~0U << 16)) : (nx_high & 0xffff);
|
|
x_low = x_low >> 1;
|
|
x_mid = nx_high >> 16;
|
|
|
|
y_low = (ny_high & 0x80000000) ? (ny_high | (~0U << 16)) : (ny_high & 0xffff);
|
|
y_low = y_low >> 1;
|
|
y_mid = ny_high >> 16;
|
|
}
|
|
}
|
|
|
|
|
|
namespace Nano3d {
|
|
|
|
static Sincos_frac16 const &sincos_frac16()
|
|
{
|
|
static Sincos_frac16 inst;
|
|
return inst;
|
|
}
|
|
|
|
|
|
static inline int sin_frac16(int angle) { return sincos_frac16().sin(angle); }
|
|
static inline int cos_frac16(int angle) { return sincos_frac16().cos(angle); }
|
|
};
|
|
|
|
#endif /* _INCLUDE__NANO3D__SINCOS_FRAC16_H_ */
|