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eina: cleanup and merge code for sin and cos. 

NOTE: this patch is part of the previous attempt to fix
rounding error. Hopefully things are better now.


SVN revision: 71150
This commit is contained in:
Cedric BAIL 2012-05-16 10:12:06 +00:00
parent 81e987e363
commit 671b3bad30
1 changed files with 5 additions and 51 deletions
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56
legacy/eina/src/lib/eina_fp.c
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@ -465,68 +465,22 @@ eina_f32p32_cos(Eina_F32p32 a)
(Eina_F32p32)eina_f32p32_fracc_get(
interpol)));
if (0 <= remainder_2PI && remainder_2PI < F32P32_PI2)
return result;
else if (F32P32_PI2 <= remainder_2PI && remainder_2PI < EINA_F32P32_PI)
return -result;
else if (EINA_F32P32_PI <= remainder_2PI && remainder_2PI < F32P32_3PI2)
return -result;
else /* if (F32P32_3PI2 <= remainder_2PI) */
return result;
if (F32P32_PI2 < remainder_2PI && remainder_2PI < F32P32_3PI2)
result *= -1;
return result;
}
EAPI Eina_F32p32
eina_f32p32_sin(Eina_F32p32 a)
{
Eina_F32p32 F32P32_2PI;
Eina_F32p32 F32P32_PI2;
Eina_F32p32 F32P32_3PI2;
Eina_F32p32 remainder_2PI;
Eina_F32p32 remainder_PI;
Eina_F32p32 interpol;
Eina_F32p32 result;
int idx;
int index2;
F32P32_2PI = EINA_F32P32_PI << 1;
F32P32_PI2 = EINA_F32P32_PI >> 1;
F32P32_3PI2 = EINA_F32P32_PI + F32P32_PI2;
/* We only have a table for cosinus, but sin(a) = cos(pi / 2 - a) */
a = eina_f32p32_sub(F32P32_PI2, a);
/* Take advantage of cosinus symetrie. */
a = eina_fp32p32_llabs(a);
/* Find table entry in 0 to PI / 2 */
remainder_PI = a - (a / EINA_F32P32_PI) * EINA_F32P32_PI;
/* Find which case from 0 to 2 * PI */
remainder_2PI = a - (a / F32P32_2PI) * F32P32_2PI;
interpol = eina_f32p32_div(eina_f32p32_scale(remainder_PI, (MAX_PREC - 1) * 2),
EINA_F32P32_PI);
idx = eina_f32p32_int_to(interpol);
if (idx >= MAX_PREC)
idx = 2 * MAX_PREC - (idx + 1);
index2 = idx + 1;
if (index2 == MAX_PREC)
index2 = idx - 1;
result = eina_f32p32_add(eina_trigo[idx],
eina_f32p32_mul(eina_f32p32_sub(eina_trigo[idx],
eina_trigo[index2]),
(Eina_F32p32)eina_f32p32_fracc_get(
interpol)));
if (0 <= remainder_2PI && remainder_2PI < F32P32_PI2)
return result;
else if (F32P32_PI2 <= remainder_2PI && remainder_2PI < EINA_F32P32_PI)
return -result;
else if (EINA_F32P32_PI <= remainder_2PI && remainder_2PI < F32P32_3PI2)
return -result;
else /* if (F32P32_3PI2 <= remainder_2PI) */
return result;
return eina_f32p32_cos(a);
}