stmbl/shared/angle.c

/*
 * This file is part of the stmbl project.
 *
 * Copyright (C) 2013-2015 Rene Hopf <renehopf@mac.com>
 * Copyright (C) 2013-2015 Nico Stute <crinq@crinq.de>
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <math.h>
#include "angle.h"
#include "defines.h"

const float sintab[257] = {
    0.000000, 0.006136, 0.012272, 0.018407, 0.024541, 0.030675, 0.036807, 0.042938,
    0.049068, 0.055195, 0.061321, 0.067444, 0.073565, 0.079682, 0.085797, 0.091909,
    0.098017, 0.104122, 0.110222, 0.116319, 0.122411, 0.128498, 0.134581, 0.140658,
    0.146730, 0.152797, 0.158858, 0.164913, 0.170962, 0.177004, 0.183040, 0.189069,
    0.195090, 0.201105, 0.207111, 0.213110, 0.219101, 0.225084, 0.231058, 0.237024,
    0.242980, 0.248928, 0.254866, 0.260794, 0.266713, 0.272621, 0.278520, 0.284408,
    0.290285, 0.296151, 0.302006, 0.307850, 0.313682, 0.319502, 0.325310, 0.331106,
    0.336890, 0.342661, 0.348419, 0.354164, 0.359895, 0.365613, 0.371317, 0.377007,
    0.382683, 0.388345, 0.393992, 0.399624, 0.405241, 0.410843, 0.416430, 0.422000,
    0.427555, 0.433094, 0.438616, 0.444122, 0.449611, 0.455084, 0.460539, 0.465977,
    0.471397, 0.476799, 0.482184, 0.487550, 0.492898, 0.498228, 0.503538, 0.508830,
    0.514103, 0.519356, 0.524590, 0.529804, 0.534998, 0.540172, 0.545325, 0.550458,
    0.555570, 0.560662, 0.565732, 0.570781, 0.575808, 0.580814, 0.585798, 0.590760,
    0.595699, 0.600617, 0.605511, 0.610383, 0.615232, 0.620057, 0.624860, 0.629638,
    0.634393, 0.639124, 0.643832, 0.648514, 0.653173, 0.657807, 0.662416, 0.667000,
    0.671559, 0.676093, 0.680601, 0.685084, 0.689541, 0.693971, 0.698376, 0.702755,
    0.707107, 0.711432, 0.715731, 0.720002, 0.724247, 0.728464, 0.732654, 0.736817,
    0.740951, 0.745058, 0.749136, 0.753187, 0.757209, 0.761202, 0.765167, 0.769103,
    0.773010, 0.776888, 0.780737, 0.784557, 0.788346, 0.792107, 0.795837, 0.799537,
    0.803208, 0.806848, 0.810457, 0.814036, 0.817585, 0.821103, 0.824589, 0.828045,
    0.831470, 0.834863, 0.838225, 0.841555, 0.844854, 0.848120, 0.851355, 0.854558,
    0.857729, 0.860867, 0.863973, 0.867046, 0.870087, 0.873095, 0.876070, 0.879012,
    0.881921, 0.884797, 0.887640, 0.890449, 0.893224, 0.895966, 0.898674, 0.901349,
    0.903989, 0.906596, 0.909168, 0.911706, 0.914210, 0.916679, 0.919114, 0.921514,
    0.923880, 0.926210, 0.928506, 0.930767, 0.932993, 0.935184, 0.937339, 0.939459,
    0.941544, 0.943593, 0.945607, 0.947586, 0.949528, 0.951435, 0.953306, 0.955141,
    0.956940, 0.958704, 0.960431, 0.962121, 0.963776, 0.965394, 0.966976, 0.968522,
    0.970031, 0.971504, 0.972940, 0.974339, 0.975702, 0.977028, 0.978317, 0.979570,
    0.980785, 0.981964, 0.983105, 0.984210, 0.985278, 0.986308, 0.987301, 0.988258,
    0.989177, 0.990058, 0.990903, 0.991710, 0.992480, 0.993212, 0.993907, 0.994565,
    0.995185, 0.995767, 0.996313, 0.996820, 0.997290, 0.997723, 0.998118, 0.998476,
    0.998795, 0.999078, 0.999322, 0.999529, 0.999699, 0.999831, 0.999925, 0.999981,
    1.000000};

void sincos_fast(float x, float *sin, float *cos) {
  extern const float sintab[257];

  x = x * 256 / (M_PI / 2);

  int y = (int)x;
  if(y < 0)
    y -= 1;

  float f = x - y;
  int i   = y & 255;

  float s = (1 - f) * sintab[i] + f * sintab[i + 1];
  float c = (1 - f) * sintab[256 - i] + f * sintab[255 - i];

  switch((y >> 8) & 3) {
    case 0:
      *sin = s;
      *cos = c;
      break;
    case 1:
      *sin = c;
      *cos = -s;
      break;
    case 2:
      *sin = -s;
      *cos = -c;
      break;
    case 3:
      *sin = -c;
      *cos = s;
      break;
    default:
      *sin = 0;
      *cos = 0;
      break;
  }
}

inline float minus(float a, float b) {
  if(ABS(a - b) < M_PI) {
    return (a - b);
  } else if(a > b) {
    return (a - b - 2.0 * M_PI);
  } else {
    return (a - b + 2.0 * M_PI);
  }
}

inline float mod(float a) {
  if(a + M_PI < 0.0f) {
    return -(fmodf(-(a + M_PI), M_PI * 2.0) - M_PI);
  } else {
    return fmodf(a + M_PI, M_PI * 2.0) - M_PI;
  }
}

int quadrant(float a) {
  if(a >= 0) {
    if(a < M_PI / 2.0) {
      return 1;
    } else {
      return 2;
    }
  } else {
    if(a < -M_PI / 2.0) {
      return 3;
    } else {
      return 4;
    }
  }
  return (0);
}

float err_filter(float *ctx, float max, float dens, float err) {
  if(err > 0.0) {
    *ctx += 1.0;
  } else {
    *ctx -= dens;
  }

  *ctx = CLAMP(*ctx, 0.0, max);

  if(*ctx < max * 0.99) {
    return (0.0);
  }
  return (1.0);
}