fish/surf/fasttrig.c

   1 #include <aros/oldprograms.h>
   2 #include <stdlib.h>
   3 #include "fasttrig.h"
   4
   5 float *sintab;
   6 float *costab;
   7
   8 extern struct Library * MathTransBase;
   9
  10 static int oldn = -1,
  11        oldrange = -1,
  12        oldstart = -1;
  13
  14
  15 /*
  16  * return true if could not get memory for trig lookup tables
  17  */
  18 bool InitFastTrig(angstart, angrange, n)
  19     int angstart;
  20     int angrange;
  21     int n;
  22 {
  23
  24
  25     int i;
  26     float AngleInc;
  27     float curangle;
  28
  29     if( n == oldn && oldrange == angrange && oldstart == angstart ) {
  30         return(false);
  31     }
  32
  33     if( n != oldn ) {
  34         if( sintab ) free(sintab);
  35         if( costab ) free(costab);
  36         sintab = (float *)malloc( n * sizeof( float ));
  37         costab = (float *)malloc( n * sizeof( float ));
  38         if( !sintab || !costab ) {
  39            return(true);
  40         }
  41     }
  42
  43     oldn = n;
  44     oldrange = angrange;
  45     oldstart = angstart;
  46
  47     AngleInc = (PI*angrange)/(180 *(n-1));
  48     for( curangle = angstart*PI/180.0, i = 0;
  49          i< n; i++, curangle += AngleInc ) {
  50
  51         sintab[i] = sin( curangle );
  52         costab[i] = cos( curangle );
  53     }
  54     return(false);
  55 }