/*
 * ap_math.c

 *
 *  Created on: 31 Jan 2016
 *      Author: Mike
 */

#include <math.h>
#include "libOLED/ap_math.h"
/* this is an approximate maths library where all the answers are accurate enough */
ap_math::ap_math()
  {
    uint16_t i;
    for(i=0;i<SINE_STEPS;i++)
   	sintab[i]=sin(i/(SINE_STEPS*2.0)*3.14159)*AP_K;
  }

/* returns 255 * sin(ang) where ang is in degrees */
int
ap_math::ap_sin (int ang)
{
  /* wrap into range */
  while (ang < 0)
    {
      ang += SINE_STEPS * 4;
    }
  while (ang >= SINE_STEPS * 4)
    {
      ang -= SINE_STEPS * 4;
    }

  if (ang >= 0 && ang < SINE_STEPS)
    {
      return (sintab[ang]);
    }
  else if (ang == SINE_STEPS)
    {
      return AP_K;
    }
  else if (ang > SINE_STEPS && ang <= SINE_STEPS * 2)
    {
      return (sintab[SINE_STEPS * 2 - ang]);
    }
  else if (ang == 3 * SINE_STEPS)
    {
      return -AP_K;
    }
  if (ang > SINE_STEPS * 2 && ang < SINE_STEPS * 3)
    {
      return (-sintab[ang - SINE_STEPS * 2]);
    }
  else
  /* ang > 270 and ang < 360 */
    {
      return (-sintab[SINE_STEPS * 4 - ang]);
    }
}

/* returns 255 * cos(ang) where ang is in degrees */
int
ap_math::ap_cos (int ang)
{
  return ap_sin (SINE_STEPS - ang);
}