From 9a10979e0f943c44a1d2df1b17a146d49b7e0e3c Mon Sep 17 00:00:00 2001
From: Tomas Frydrych <tf@openedhand.com>
Date: Wed, 16 May 2007 13:46:54 +0000
Subject: [PATCH] Fixed clutter_sine_inc_func(); added clutter_sine_dec_func()

---
 ChangeLog                          |  7 ++++
 clutter/clutter-alpha.c            | 59 ++++++++++++++++++++++++++----
 clutter/clutter-alpha.h            |  7 +++-
 doc/reference/clutter-sections.txt |  4 ++
 4 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6d4764892..8ba46d3c5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-05-16  Tomas Frydrych  <tf@openedhand.com>
+	
+	* clutter/clutter-alpha.h:
+	* clutter/clutter-alpha.c:
+	* doc/reference/clutter-sections.txt:
+	Fixed clutter_sine_inc(), added clutter_sine_dec().
+	
 2007-05-16  Tomas Frydrych  <tf@openedhand.com>
 	
 	* clutter/clutter-alpha.h:
diff --git a/clutter/clutter-alpha.c b/clutter/clutter-alpha.c
index 6f084ada8..adadf6b74 100644
--- a/clutter/clutter-alpha.c
+++ b/clutter/clutter-alpha.c
@@ -603,8 +603,9 @@ clutter_sine_func (ClutterAlpha *alpha,
  * @alpha: a #ClutterAlpha
  * @dummy: unused argument
  *
- * Convenience alpha function for a sine wave. You can use this
- * function as the alpha function for clutter_alpha_set_func().
+ * Convenience alpha function for a sine wave over interval <0, pi/2>.
+ * You can use this function as the alpha function for
+ * clutter_alpha_set_func().
  *
  * Return value: an alpha value.
  *
@@ -614,11 +615,55 @@ guint32
 clutter_sine_inc_func (ClutterAlpha *alpha,
 		       gpointer      dummy)
 {
-#if 0
-  return sinc_func (alpha, 0.5, 1.0);
-#else
-  return sincx1024_func (alpha, 256, CFX_ONE);
-#endif
+  ClutterTimeline * timeline;
+  gint              frame;
+  gint              n_frames;
+  ClutterAngle      x;
+  ClutterFixed      sine;
+  
+  timeline = clutter_alpha_get_timeline (alpha);
+  frame    = clutter_timeline_get_current_frame (timeline);
+  n_frames = clutter_timeline_get_n_frames (timeline);
+
+  x = 256 * frame / n_frames;
+
+  sine = clutter_sini (x) * CLUTTER_ALPHA_MAX_ALPHA;
+
+  return CFX_INT (sine);
+}
+
+/**
+ * clutter_sine_dec_func:
+ * @alpha: a #ClutterAlpha
+ * @dummy: unused argument
+ *
+ * Convenience alpha function for a sine wave over interval <pi/2, pi>.
+ * You can use this function as the alpha function for
+ * clutter_alpha_set_func().
+ *
+ * Return value: an alpha value.
+ *
+ * Since: 0.4
+ */
+guint32 
+clutter_sine_dec_func (ClutterAlpha *alpha,
+		       gpointer      dummy)
+{
+  ClutterTimeline * timeline;
+  gint              frame;
+  gint              n_frames;
+  ClutterAngle      x;
+  ClutterFixed      sine;
+  
+  timeline = clutter_alpha_get_timeline (alpha);
+  frame    = clutter_timeline_get_current_frame (timeline);
+  n_frames = clutter_timeline_get_n_frames (timeline);
+
+  x = 256 * frame / n_frames + 256;
+
+  sine = clutter_sini (x) * CLUTTER_ALPHA_MAX_ALPHA;
+
+  return CFX_INT (sine);
 }
 
 /**
diff --git a/clutter/clutter-alpha.h b/clutter/clutter-alpha.h
index cac98320e..fb4d40e01 100644
--- a/clutter/clutter-alpha.h
+++ b/clutter/clutter-alpha.h
@@ -106,7 +106,8 @@ ClutterTimeline *clutter_alpha_get_timeline (ClutterAlpha     *alpha);
 #define CLUTTER_ALPHA_RAMP_DEC   clutter_ramp_dec_func
 #define CLUTTER_ALPHA_RAMP       clutter_ramp_func
 #define CLUTTER_ALPHA_SINE       clutter_sine_func
-/* FIXME add SINE_INC/DEC */
+#define CLUTTER_ALPHA_SINE_INC   clutter_sine_inc_func
+#define CLUTTER_ALPHA_SINE_DEC   clutter_sine_dec_func
 #define CLUTTER_ALPHA_SQUARE     clutter_square_func
 #define CLUTTER_ALPHA_SMOOTHSTEP clutter_smoothstep_func
 
@@ -132,6 +133,10 @@ guint32             clutter_ramp_func          (ClutterAlpha     *alpha,
 						gpointer          dummy);
 guint32             clutter_sine_func          (ClutterAlpha     *alpha,
 						gpointer          dummy);
+guint32             clutter_sine_inc_func      (ClutterAlpha     *alpha,
+						gpointer          dummy);
+guint32             clutter_sine_dec_func      (ClutterAlpha     *alpha,
+						gpointer          dummy);
 guint32             clutter_square_func        (ClutterAlpha     *alpha,
 						gpointer          dummy);
 guint32             clutter_smoothstep_func    (ClutterAlpha     *alpha,
diff --git a/doc/reference/clutter-sections.txt b/doc/reference/clutter-sections.txt
index ca97a8e47..1621337e8 100644
--- a/doc/reference/clutter-sections.txt
+++ b/doc/reference/clutter-sections.txt
@@ -112,6 +112,10 @@ CLUTTER_ALPHA_RAMP
 clutter_ramp_func
 CLUTTER_ALPHA_SINE
 clutter_sine_func
+CLUTTER_ALPHA_SINE_INC
+clutter_sine_inc_func
+CLUTTER_ALPHA_SINE_DEC
+clutter_sine_dec_func
 CLUTTER_ALPHA_SQUARE
 clutter_square_func
 CLUTTER_ALPHA_SMOOTHSTEP