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pluged clutter_fixed_sin into clutter-alpha; updated change log

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Tomas Frydrych
2007-01-15 19:43:09 +00:00
parent 95840c47bf
commit 44a89898ca
3 changed files with 69 additions and 24 deletions
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55
clutter/clutter-fixed.c
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@ -83,49 +83,60 @@ static ClutterFixed sin_tbl [] =
*/
#define CFX_SIN_STEP 0x00000192
/**
* clutter_fixed_sin:
* @angle: a #ClutterAlpha
*
* Fixed point implementation of sine function
* Return value: sine value (as fixed point).
*
* Since: 0.2
*/
ClutterFixed
clutter_fixed_sin (ClutterFixed anx)
clutter_fixed_sin (ClutterFixed angle)
{
int sign = 1, indx1, indx2;
ClutterFixed low, high, d1, d2;
/* reduce to <0, 2*pi) */
if (anx >= CFX_2PI)
if (angle >= CFX_2PI)
{
ClutterFixed f = CLUTTER_FIXED_DIV (anx, CFX_2PI);
anx = anx - f;
ClutterFixed f = CLUTTER_FIXED_DIV (angle, CFX_2PI);
angle = angle - f;
}
/* reduce to first quadrant and sign */
int sign = 1;
if (anx > CFX_PI)
if (angle > CFX_PI)
{
sign = -1;
if (anx > CFX_PI + CFX_PI_2)
if (angle > CFX_PI + CFX_PI_2)
{
/* fourth qudrant */
anx = CFX_2PI - anx;
angle = CFX_2PI - angle;
}
else
{
/* third quadrant */
anx -= CFX_PI;
angle -= CFX_PI;
}
}
else
{
if (anx > CFX_PI_2)
if (angle > CFX_PI_2)
{
/* second quadrant */
anx = CFX_PI - anx;
angle = CFX_PI - angle;
}
}
/* Calculate indexes of the two nearest values in our table
/* Calculate indices of the two nearest values in our table
* and return weighted average
*
* Handle the end of the table gracefully
*/
int indx1 = CLUTTER_FIXED_DIV (anx, CFX_SIN_STEP);
int indx2;
indx1 = CLUTTER_FIXED_DIV (angle, CFX_SIN_STEP);
indx2;
indx1 = CLUTTER_FIXED_INT (indx1);
@ -139,16 +150,16 @@ clutter_fixed_sin (ClutterFixed anx)
indx2 = indx1 + 1;
}
ClutterFixed low = sin_tbl[indx1];
ClutterFixed high = sin_tbl[indx2];
low = sin_tbl[indx1];
high = sin_tbl[indx2];
ClutterFixed d1 = anx - indx1 * CFX_SIN_STEP;
ClutterFixed d2 = indx2 * CFX_SIN_STEP - anx;
d1 = angle - indx1 * CFX_SIN_STEP;
d2 = indx2 * CFX_SIN_STEP - angle;
anx = ((low * d2 + high * d1) / (CFX_SIN_STEP));
angle = ((low * d2 + high * d1) / (CFX_SIN_STEP));
if (sign < 0)
anx = (1 + ~anx);
angle = (1 + ~angle);
return anx;
return angle;
}