hermet pushed a commit to branch master.
http://git.enlightenment.org/core/efl.git/commit/?id=3b6a5956f9dba282720fb779ed01800305eb5674
commit 3b6a5956f9dba282720fb779ed01800305eb5674
Author: ChunEon Park <her...@hermet.pe.kr>
Date: Tue Dec 9 16:27:29 2014 +0900
ecore/animator: fix the wrong computation of bezier cubic.
Previous beizer cubic finds t value approximately.
In this sequence, there were 2 problems.
1. Previous guess_t value should be passed to differential equation to get
the more accurate t value.
2. Guessing time count is not enough. I found 6 is enough time to get the t
value experimentally. Previously it just tried 4 times on the other hand.
@fix
---
src/lib/ecore/ecore_anim.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/src/lib/ecore/ecore_anim.c b/src/lib/ecore/ecore_anim.c
index e248f05..a59320a 100644
--- a/src/lib/ecore/ecore_anim.c
+++ b/src/lib/ecore/ecore_anim.c
@@ -350,15 +350,24 @@ _cubic_bezier_t_get(double a,
double x1,
double x2)
{
+#define APPROXIMATE_RANGE(val) \
+ ((((val) < 0.01) && ((val) > -0.01)) ? EINA_TRUE : EINA_FALSE)
+
+ const int LIMIT = 100;
+ double current_slope;
+ double tmp;
+ double current_x;
double guess_t = a;
- for (int i = 0; i < 4; ++i)
- {
- double current_slope = _cubic_bezier_slope_get(a, x1, x2);
- if (current_slope == 0.0)
- return guess_t;
- double current_x = _cubic_bezier_calc(guess_t, x1, x2) - a;
- guess_t -= current_x / current_slope;
- }
+
+ for (int i = 0; i < LIMIT; i++)
+ {
+ current_slope = _cubic_bezier_slope_get(guess_t, x1, x2);
+ if (current_slope == 0.0) return guess_t;
+ current_x = _cubic_bezier_calc(guess_t, x1, x2) - a;
+ tmp = current_x / current_slope;
+ guess_t -= current_x / current_slope;
+ if (APPROXIMATE_RANGE(tmp)) break;
+ }
return guess_t;
}
--
