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4 mjames 1 
/*
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 * ap_math.c
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 *
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 *  Created on: 31 Jan 2016
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 *      Author: Mike
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 */
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#include <math.h>
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#include "libOLED/ap_math.h"
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namespace
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{
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   static constexpr uint8_t sintab[ap_math::SINE_STEPS] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24,
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                             25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47,
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                             48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 69, 70,
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                             71, 72, 73, 74, 75, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,
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                             93, 94, 95, 96, 97, 98, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
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                             112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 127,
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                             128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144,
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                             144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 154, 155, 156, 157, 158, 159,
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                             160, 161, 161, 162, 163, 164, 165, 166, 167, 167, 168, 169, 170, 171, 172, 172, 173,
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                             174, 175, 176, 177, 177, 178, 179, 180, 181, 181, 182, 183, 184, 184, 185, 186, 187,
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                             187, 188, 189, 190, 190, 191, 192, 193, 193, 194, 195, 196, 196, 197, 198, 198, 199,
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                             200, 201, 201, 202, 203, 203, 204, 205, 205, 206, 207, 207, 208, 209, 209, 210, 210,
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                             211, 212, 212, 213, 214, 214, 215, 215, 216, 217, 217, 218, 218, 219, 220, 220, 221,
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                             221, 222, 222, 223, 223, 224, 224, 225, 226, 226, 227, 227, 228, 228, 229, 229, 230,
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                             230, 231, 231, 232, 232, 232, 233, 233, 234, 234, 235, 235, 236, 236, 236, 237, 237,
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                             238, 238, 238, 239, 239, 240, 240, 240, 241, 241, 242, 242, 242, 243, 243, 243, 244,
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                             244, 244, 245, 245, 245, 246, 246, 246, 246, 247, 247, 247, 248, 248, 248, 248, 249,
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                             249, 249, 249, 250, 250, 250, 250, 251, 251, 251, 251, 251, 252, 252, 252, 252, 252,
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                             253, 253, 253, 253, 253, 253, 253, 254, 254, 254, 254, 254, 254, 254, 254, 255, 255,
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                             255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255} ;
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}
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4 mjames 36 
/* this is an approximate maths library where all the answers are accurate enough */
12 mjames 37 
ap_math::ap_math()
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{
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}
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int ap_math::ap_sin(int ang)
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{
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  /* wrap into range */
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  while (ang < 0)
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  {
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    ang += SINE_STEPS * 4;
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  }
4 mjames 48 
  while (ang >= SINE_STEPS * 4)
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  {
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    ang -= SINE_STEPS * 4;
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  }
4 mjames 52 
 
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  if (ang >= 0 && ang < SINE_STEPS)
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  {
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    return (sintab[ang]);
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  }
4 mjames 57 
  else if (ang == SINE_STEPS)
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  {
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    return AP_K;
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  }
4 mjames 61 
  else if (ang > SINE_STEPS && ang <= SINE_STEPS * 2)
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  {
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    return (sintab[SINE_STEPS * 2 - ang]);
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  }
4 mjames 65 
  else if (ang == 3 * SINE_STEPS)
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  {
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    return -AP_K;
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  }
4 mjames 69 
  if (ang > SINE_STEPS * 2 && ang < SINE_STEPS * 3)
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  {
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    return (-sintab[ang - SINE_STEPS * 2]);
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  }
4 mjames 73 
  else
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  /* ang > 270 and ang < 360 */
12 mjames 75 
  {
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    return (-sintab[SINE_STEPS * 4 - ang]);
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  }
4 mjames 78 
}
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/* returns 255 * cos(ang) where ang is in degrees */
12 mjames 81 
int ap_math::ap_cos(int ang)
4 mjames 82 
{
12 mjames 83 
  return ap_sin(SINE_STEPS - ang);
4 mjames 84 
}