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#include <stdlib.h>
#include <avr/pgmspace.h>
#include "mymath.h"
// discrete mathematics
// Sinus with argument in degree at an angular resolution of 1 degree and a discretisation of 13 bit.
const uint16_t pgm_sinlookup
[91] PROGMEM
= {0, 143, 286, 429, 571, 714, 856, 998, 1140, 1282, 1423, 1563, 1703, 1843, 1982, 2120, 2258, 2395, 2531, 2667, 2802, 2936, 3069, 3201, 3332, 3462, 3591, 3719, 3846, 3972, 4096, 4219, 4341, 4462, 4581, 4699, 4815, 4930, 5043, 5155, 5266, 5374, 5482, 5587, 5691, 5793, 5893, 5991, 6088, 6183, 6275, 6366, 6455, 6542, 6627, 6710, 6791, 6870, 6947, 7022, 7094, 7165, 7233, 7299, 7363, 7424, 7484, 7541, 7595, 7648, 7698, 7746, 7791, 7834, 7875, 7913, 7949, 7982, 8013, 8041, 8068, 8091, 8112, 8131, 8147, 8161, 8172, 8181, 8187, 8191, 8192};
int16_t c_sin_8192
(int16_t angle
)
{
int8_t m
,n
;
int16_t sinus
;
// avoid negative angles
if (angle
< 0)
{
m
= -1;
angle
= abs(angle
);
}
else m
= +1;
// fold angle to intervall 0 to 359
angle
%= 360;
// check quadrant
if (angle
<= 90) n
=1; // first quadrant
else if ((angle
> 90) && (angle
<= 180)) {angle
= 180 - angle
; n
= 1;} // second quadrant
else if ((angle
> 180) && (angle
<= 270)) {angle
= angle
- 180; n
= -1;} // third quadrant
else {angle
= 360 - angle
; n
= -1;} //fourth quadrant
// get lookup value
sinus
= pgm_read_word
(&pgm_sinlookup
[angle
]);
// calculate sinus value
return (sinus
* m
* n
);
}
// Cosinus with argument in degree at an angular resolution of 1 degree and a discretisation of 13 bit.
int16_t c_cos_8192
(int16_t angle
)
{
return (c_sin_8192
(90 - angle
));
}
// Arcustangens returns degree in a range of +/. 180 deg
const uint8_t pgm_atanlookup
[346] PROGMEM
= {0,1,2,3,4,4,5,6,7,8,9,10,11,11,12,13,14,15,16,17,17,18,19,20,21,21,22,23,24,24,25,26,27,27,28,29,29,30,31,31,32,33,33,34,35,35,36,36,37,37,38,39,39,40,40,41,41,42,42,43,43,44,44,45,45,45,46,46,47,47,48,48,48,49,49,50,50,50,51,51,51,52,52,52,53,53,53,54,54,54,55,55,55,55,56,56,56,57,57,57,57,58,58,58,58,59,59,59,59,60,60,60,60,60,61,61,61,61,62,62,62,62,62,63,63,63,63,63,63,64,64,64,64,64,64,65,65,65,65,65,65,66,66,66,66,66,66,66,67,67,67,67,67,67,67,68,68,68,68,68,68,68,68,69,69,69,69,69,69,69,69,69,70,70,70,70,70,70,70,70,70,71,71,71,71,71,71,71,71,71,71,71,72,72,72,72,72,72,72,72,72,72,72,73,73,73,73,73,73,73,73,73,73,73,73,73,73,74,74,74,74,74,74,74,74,74,74,74,74,74,74,75,75,75,75,75,75,75,75,75,75,75,75,75,75,75,75,75,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79};
int16_t c_atan2
(int16_t y
, int16_t x
)
{
int16_t index
, angle
;
int8_t m
;
if (!x
&& !y
) return 0; //atan2(0, 0) is undefined
if (y
< 0) m
= -1;
else m
= 1;
if (!x
) return (90 * m
); // atan2(y,0) = +/- 90 deg
index
= (int16_t)(((int32_t)y
* 64) / x
);// calculate index for lookup table
if (index
< 0) index
= -index
;
if (index
< 346) angle
= pgm_read_byte
(&pgm_atanlookup
[index
]); // lookup for 0 deg to 79 deg
else if (index
> 7334) angle
= 90; // limit is 90 deg
else if (index
> 2444) angle
= 89; // 89 deg to 80 deg is mapped via intervalls
else if (index
> 1465) angle
= 88;
else if (index
> 1046) angle
= 87;
else if (index
> 813) angle
= 86;
else if (index
> 664) angle
= 85;
else if (index
> 561) angle
= 84;
else if (index
> 486) angle
= 83;
else if (index
> 428) angle
= 82;
else if (index
> 382) angle
= 81;
else angle
= 80; // (index>345)
if (x
> 0) return (angle
* m
); // 1st and 4th quadrant
else if ((x
< 0) && (m
> 0)) return (180 - angle
); // 2nd quadrant
else return (angle
- 180); // ( (x < 0) && (y < 0)) 3rd quadrant
}