/**
 * Defines fast math functions
 *
 * 
 * fsin - a fast sine approximation
 * fcos - a fast cosine approximation
 */

#ifndef FMATH_H
#define FMATH_H

/* lookuptable for 90 degrees in 360 steps! */
float sintab[90*4+1] =
  {
    0.000000,0.004363,0.008727,0.013090,0.017452,0.021815,0.026177,0.030539,
    0.034899,0.039260,0.043619,0.047978,0.052336,0.056693,0.061049,0.065403,
    0.069756,0.074108,0.078459,0.082808,0.087156,0.091502,0.095846,0.100188,
    0.104528,0.108867,0.113203,0.117537,0.121869,0.126199,0.130526,0.134851,
    0.139173,0.143493,0.147809,0.152123,0.156434,0.160743,0.165048,0.169350,
    0.173648,0.177944,0.182236,0.186524,0.190809,0.195090,0.199368,0.203642,
    0.207912,0.212178,0.216440,0.220697,0.224951,0.229200,0.233445,0.237686,
    0.241922,0.246153,0.250380,0.254602,0.258819,0.263031,0.267238,0.271440,
    0.275637,0.279829,0.284015,0.288196,0.292372,0.296542,0.300706,0.304864,
    0.309017,0.313164,0.317305,0.321439,0.325568,0.329691,0.333807,0.337917,
    0.342020,0.346117,0.350207,0.354291,0.358368,0.362438,0.366501,0.370557,
    0.374607,0.378649,0.382683,0.386711,0.390731,0.394744,0.398749,0.402747,
    0.406737,0.410719,0.414693,0.418660,0.422618,0.426569,0.430511,0.434445,
    0.438371,0.442289,0.446198,0.450098,0.453990,0.457874,0.461749,0.465615,
    0.469472,0.473320,0.477159,0.480989,0.484810,0.488621,0.492424,0.496217,
    0.500000,0.503774,0.507538,0.511293,0.515038,0.518773,0.522499,0.526214,
    0.529919,0.533615,0.537300,0.540974,0.544639,0.548293,0.551937,0.555570,
    0.559193,0.562805,0.566406,0.569997,0.573576,0.577145,0.580703,0.584250,
    0.587785,0.591310,0.594823,0.598325,0.601815,0.605294,0.608761,0.612217,
    0.615661,0.619094,0.622515,0.625923,0.629320,0.632705,0.636078,0.639439,
    0.642788,0.646124,0.649448,0.652760,0.656059,0.659346,0.662620,0.665882,
    0.669131,0.672367,0.675590,0.678801,0.681998,0.685183,0.688355,0.691513,
    0.694658,0.697790,0.700909,0.704015,0.707107,0.710185,0.713250,0.716302,
    0.719340,0.722364,0.725374,0.728371,0.731354,0.734323,0.737277,0.740218,
    0.743145,0.746057,0.748956,0.751840,0.754710,0.757565,0.760406,0.763232,
    0.766044,0.768842,0.771625,0.774393,0.777146,0.779884,0.782608,0.785317,
    0.788011,0.790690,0.793353,0.796002,0.798636,0.801254,0.803857,0.806445,
    0.809017,0.811574,0.814116,0.816642,0.819152,0.821647,0.824126,0.826590,
    0.829038,0.831470,0.833886,0.836286,0.838671,0.841039,0.843391,0.845728,
    0.848048,0.850352,0.852640,0.854912,0.857167,0.859406,0.861629,0.863836,
    0.866025,0.868199,0.870356,0.872496,0.874620,0.876727,0.878817,0.880891,
    0.882948,0.884988,0.887011,0.889017,0.891007,0.892979,0.894934,0.896873,
    0.898794,0.900698,0.902585,0.904455,0.906308,0.908143,0.909961,0.911762,
    0.913545,0.915311,0.917060,0.918791,0.920505,0.922201,0.923880,0.925541,
    0.927184,0.928810,0.930418,0.932008,0.933580,0.935135,0.936672,0.938191,
    0.939693,0.941176,0.942641,0.944089,0.945519,0.946930,0.948324,0.949699,
    0.951057,0.952396,0.953717,0.955020,0.956305,0.957571,0.958820,0.960050,
    0.961262,0.962455,0.963630,0.964787,0.965926,0.967046,0.968148,0.969231,
    0.970296,0.971342,0.972370,0.973379,0.974370,0.975342,0.976296,0.977231,
    0.978148,0.979045,0.979925,0.980785,0.981627,0.982450,0.983255,0.984041,
    0.984808,0.985556,0.986286,0.986996,0.987688,0.988362,0.989016,0.989651,
    0.990268,0.990866,0.991445,0.992005,0.992546,0.993068,0.993572,0.994056,
    0.994522,0.994969,0.995396,0.995805,0.996195,0.996566,0.996917,0.997250,
    0.997564,0.997859,0.998135,0.998392,0.998630,0.998848,0.999048,0.999229,
    0.999391,0.999534,0.999657,0.999762,0.999848,0.999914,0.999962,0.999990,
    1.000000
  };

/* approx. sin in the range (-PI <-> PI) */
float fsin(float x)
{
  int deg;

  deg = (int)((x*180*4)/M_PI);

  if(deg<0)
    {
      if(deg<-90*4)
        if(deg<-180*4)
          return 0;                   /* out of range */
        else
          return (-sintab[deg+180*4]);
      else
        return (-sintab[-deg]);
    }
  else
    {
      if(deg>90*4)
        if(deg>180*4)
          return 0;                   /* out of range */
        else
          return (sintab[180*4-deg]);
      else
        return (sintab[deg]);
    }
}

/* approx. cos in the range (-PI <-> PI) */
float fcos(float x)
{
  int deg;

  deg = (int)((x*180*4)/M_PI);

  if(deg<0)
    {
      if(deg<-90*4)
        if(deg<-180*4)
          return 0;                   /* out of range */
        else
          return (-sintab[-(deg+90*4)]);
      else
        return (sintab[deg+90*4]);
    }
  else
    {
      if(deg>90*4)
        if(deg>180*4)
          return 0;                   /* out of range */
        else
          return (-sintab[deg-90*4]);
      else
        return (sintab[90*4-deg]);
    }
}


#endif