brl/mutter
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fixed clutter cos functions; fixed tilt calculations in elliptic path

Browse Source
This commit is contained in:
Tomas Frydrych 2007-05-29 09:21:18 +00:00
parent 5b845d3940
commit 6e39efb9aa
4 changed files with 37 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
ChangeLog
View File

@ -1,3 +1,18 @@
2007-05-29 Tomas Frydrych <tf@openedhand.com>
* clutter/clutter-fixed.h:
(clutter_cosx):
(clutter_cosi):
Fixed wrong sign in cos -> sin tranformation.
* clutter/clutter-behaviour-ellipse.c:
(clutter_behaviour_ellipse_advance):
Replaced coordinace calculation for tilted ellipse with a sane
algorithm.
* examples/behave.c:
Added tilt parameter to the example ellptic path.
2007-05-29 Tomas Frydrych <tf@openedhand.com> 2007-05-29 Tomas Frydrych <tf@openedhand.com>
* clutter/cogl/gles/cogl.c: * clutter/cogl/gles/cogl.c:

41
clutter/clutter-behaviour-ellipse.c
View File

@ -111,33 +111,30 @@ clutter_behaviour_ellipse_advance (ClutterBehaviourEllipse * e,
if (e->priv->angle_tilt) if (e->priv->angle_tilt)
{ {
/* Problem: sqrti is not giving us sufficient precission here /*
* and ClutterFixed range is too small to hold x^2+y^2 even for * x2 = r * cos (angle + tilt)
* reasonable x, y values. * y2 = r * sin (angle + tilt)
*
* These can be trasformed to the formulas below using properties of
* sin (a + b) and cos (a + b)
* *
* We take advantage of sqrt (a * b^2) == sqrt (a) * b,
* and divide repeatedly by 4 until we get it into range, and then
* multiply the result by 2 the same number of times.
*/ */
ClutterFixed r; ClutterFixed x2, y2;
guint q = x*x + y*y;
gint shift = 0;
while (q > G_MAXINT16) x2 = x * clutter_cosi (e->priv->angle_tilt) -
{ y * clutter_sini (e->priv->angle_tilt);
++shift;
q >>= 2;
}
r = clutter_sqrtx (CLUTTER_INT_TO_FIXED (q)) << shift; y2 = y * clutter_cosi (e->priv->angle_tilt) +
x * clutter_sini (e->priv->angle_tilt);
x = CFX_INT (CFX_MUL (r, clutter_cosi (angle + e->priv->angle_tilt)));
y = CFX_INT (CFX_MUL (r, clutter_sini (angle + e->priv->angle_tilt))); knot->x = CFX_INT (x2);
knot->y = CFX_INT (y2);
}
else
{
knot->x = x;
knot->y = y;
} }
knot->x = x;
knot->y = y;
#if 0 #if 0
g_debug ("advancing to angle %d [%d, %d] (a: %d, b: %d)", g_debug ("advancing to angle %d [%d, %d] (a: %d, b: %d)",

4
clutter/clutter-fixed.h
View File

@ -171,7 +171,7 @@ ClutterFixed clutter_tani (ClutterAngle angle);
* *
* Since: 0.2 * Since: 0.2
*/ */
#define clutter_cosx(angle) clutter_fixed_sin((angle) - CFX_PI_2) #define clutter_cosx(angle) clutter_fixed_sin((angle) + CFX_PI_2)
/** /**
* clutter_cosi: * clutter_cosi:
@ -188,7 +188,7 @@ ClutterFixed clutter_tani (ClutterAngle angle);
* *
* Since: 0.2 * Since: 0.2
*/ */
#define clutter_cosi(angle) clutter_sini((angle) - 256) #define clutter_cosi(angle) clutter_sini((angle) + 256)
ClutterFixed clutter_sqrtx (ClutterFixed x); ClutterFixed clutter_sqrtx (ClutterFixed x);
gint clutter_sqrti (gint x); gint clutter_sqrti (gint x);

2
examples/behave.c
View File

@ -166,7 +166,7 @@ main (int argc, char *argv[])
case PATH_ELLIPSE: case PATH_ELLIPSE:
p_behave = p_behave =
clutter_behaviour_ellipse_new (alpha, 200, 200, 400, 300, clutter_behaviour_ellipse_new (alpha, 200, 200, 400, 300,
0.0, 360.0, 0.0); 0.0, 360.0, 120.0);
break; break;
case PATH_BSPLINE: case PATH_BSPLINE: