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fixed fixed point clutter_sine_func

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Tomas Frydrych 2007-01-30 19:35:19 +00:00
parent 9661bd50b8
commit 271e877593
2 changed files with 22 additions and 22 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2007-01-30 Tomas Frydrych <tf@openedhand.com>
* clutter/clutter-alpha.c:
(sincx1024_func):
(clutter_sine_func):
(clutter_sine_inc_func):
fixed the fixed point math.
2007-01-30 Emmanuele Bassi <ebassi@openedhand.com> 2007-01-30 Emmanuele Bassi <ebassi@openedhand.com>
* clutter/clutter-alpha.h: * clutter/clutter-alpha.h:

31
clutter/clutter-alpha.c
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@ -499,7 +499,7 @@ sincx1024_func (ClutterAlpha *alpha,
ClutterTimeline *timeline; ClutterTimeline *timeline;
gint current_frame_num, n_frames; gint current_frame_num, n_frames;
ClutterAngle x; ClutterAngle x;
ClutterFixed sine; unsigned int sine;
timeline = clutter_alpha_get_timeline (alpha); timeline = clutter_alpha_get_timeline (alpha);
@ -508,16 +508,13 @@ sincx1024_func (ClutterAlpha *alpha,
x = angle * current_frame_num / n_frames; x = angle * current_frame_num / n_frames;
/* x -= (512 * 512 / angle);
* x = x*PI - PI/angle
*/
x = (x << 9) - (512 / angle);
sine = (clutter_sini (x) + offset)/2; sine = ((clutter_sini (x) + offset)/2) * CLUTTER_ALPHA_MAX_ALPHA;
CLUTTER_NOTE (ALPHA, "sine: %2f\n", CLUTTER_FIXED_TO_DOUBLE (sine)); sine = sine >> CFX_Q;
return CLUTTER_FIXED_INT (sine * CLUTTER_ALPHA_MAX_ALPHA); return sine;
} }
#if 0 #if 0
/* /*
@ -548,6 +545,9 @@ sincx_func (ClutterAlpha *alpha,
return CLUTTER_FIXED_INT (sine * CLUTTER_ALPHA_MAX_ALPHA); return CLUTTER_FIXED_INT (sine * CLUTTER_ALPHA_MAX_ALPHA);
} }
/* NB: angle is not in radians but in muliples of PI, i.e., 2.0
* represents full circle.
*/
static guint32 static guint32
sinc_func (ClutterAlpha *alpha, sinc_func (ClutterAlpha *alpha,
float angle, float angle,
@ -567,7 +567,7 @@ sinc_func (ClutterAlpha *alpha,
x = (gdouble) (current_frame_num * angle * M_PI) / n_frames ; x = (gdouble) (current_frame_num * angle * M_PI) / n_frames ;
sine = (sin (x - (M_PI / angle)) + offset) * 0.5f; sine = (sin (x - (M_PI / angle)) + offset) * 0.5f;
CLUTTER_NOTE (ALPHA, "sine: %2f\n", sine); CLUTTER_NOTE (ALPHA, "sine: %2f\n",sine);
return CLUTTER_FLOAT_TO_INT ((sine * (gdouble) CLUTTER_ALPHA_MAX_ALPHA)); return CLUTTER_FLOAT_TO_INT ((sine * (gdouble) CLUTTER_ALPHA_MAX_ALPHA));
} }
@ -592,11 +592,8 @@ clutter_sine_func (ClutterAlpha *alpha,
#if 0 #if 0
return sinc_func (alpha, 2.0, 1.0); return sinc_func (alpha, 2.0, 1.0);
#else #else
/* Conversion to ClutterAngle: /* 2.0 above represents full circle */
* return sincx1024_func (alpha, 1024, CFX_ONE);
* 2.0 rad -> 1024*2.0/(2*PI) = 325.949
*/
return sincx1024_func (alpha, 326, CFX_ONE);
#endif #endif
} }
@ -619,11 +616,7 @@ clutter_sine_inc_func (ClutterAlpha *alpha,
#if 0 #if 0
return sinc_func (alpha, 0.5, 1.0); return sinc_func (alpha, 0.5, 1.0);
#else #else
/* Conversion to ClutterAngle: return sincx1024_func (alpha, 256, CFX_ONE);
*
* 0.5 rad -> 1024*0.5/(2*PI) = 81.487
*/
return sincx1024_func (alpha, 81, CFX_ONE);
#endif #endif
} }