Merge pull request #562 from crmagicxxx/EaseSineActions

Adding Ease Sine actions

Former-commit-id: 481c158

Author: cocojoe

cocos2d/CCActionEase.h

@@ -59,6 +59,31 @@
 @end
 
 
+#pragma mark - Ease Sine Actions
+/**
+ *  This action will start the specified action with an sine effect.
+ *
+ *  Note: This action doesn't use a bijective function, actions like CCActionSequence might have an unexpected result when used with this action.
+ */
+@interface CCActionEaseSineIn : CCActionEase <NSCopying>
+@end
+
+/**
+ *  This action will start the specified action with an sine effect.
+ *
+ *  Note: This action doesn't use a bijective function, actions like CCActionSequence might have an unexpected result when used with this action.
+ */
+@interface CCActionEaseSineOut : CCActionEase <NSCopying>
+@end
+
+/**
+ *  This action will start the specified action with an sine effect.
+ *
+ *  Note: This action doesn't use a bijective function, actions like CCActionSequence might have an unexpected result when used with this action.
+ */
+@interface CCActionEaseSineInOut : CCActionEase <NSCopying>
+@end
+
 /**
  *  This action will start the specified action with a reversed acceleration.
  *

cocos2d/CCActionEase.m

@@ -93,6 +93,47 @@ -(CCActionInterval*) reverse
 @end
 
 
+#pragma mark - Ease Sine Actions
+//
+// EaseSineIn
+//
+@implementation CCActionEaseSineIn
+-(void) update: (CCTime) t
+{
+	[_inner update:-1*cosf(t * (float)M_PI_2) +1];
+}
+
+- (CCActionInterval*) reverse
+{
+	return [CCActionEaseSineOut actionWithAction: [_inner reverse]];
+}
+@end
+
+//
+// EaseSineOut
+//
+@implementation CCActionEaseSineOut
+-(void) update: (CCTime) t
+{
+	[_inner update:sinf(t * (float)M_PI_2)];
+}
+
+- (CCActionInterval*) reverse
+{
+	return [CCActionEaseSineIn actionWithAction: [_inner reverse]];
+}
+@end
+
+//
+// EaseSineInOut
+//
+@implementation CCActionEaseSineInOut
+-(void) update: (CCTime) t
+{
+	[_inner update:-0.5f*(cosf( (float)M_PI*t) - 1)];
+}
+@end
+
 #pragma mark -
 #pragma mark EaseRate