How to make cocos2d sprite scale up and down (for a pulsating effect) every second?

Question

I want to have a sprite scale up and down once every second to make it seem like it is bulging and pulsating. How can I do this?

Answer 1

You could use a simple [CCScaleTo ..] action or if you want to create your own "effect" you could advance the CCFiniteTimeAction. I would prefer the first one :

CCSprite * sprite = ...; // create the sprite.
sprite.anchorPoint = ccp( 0.5, 0.5 ); center the pivot
id myAction = [CCRepeatForEver actionWithActions:[CCScaleTo actionWithDuration:0.5 scaleX:2.0 ScaleY:2.0],[CCScaleTo actionWithDuration:0.5 scaleX:0.5 ScaleY:0.5], nil];
[sprite runAction:myAction];

use CCEase to make the animation nonlinear

id myAction = [CCRepeatForEver actionWithActions:[CCEaseInOut actionWithAction:[CCScaleTo actionWithDuration:0.5 scaleX:2.0 ScaleY:2.0] rate:2.0],[CCEaseInOut actionWithAction:[CCScaleTo actionWithDuration:0.5 scaleX:0.5 ScaleY:0.5] rate:2.0], nil];

this post may contain errors. but I hope you understand the way to come to the goal.