Fading sprites sequentially « cocos2d for iPhone

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Fading sprites sequentially

(9 posts) (4 voices)

Started 2 years ago by stu
Latest reply from Clain

Tags:

I can't figure out how to fade my sprites sequentially, one after the other. It looks like the actions are being spawned and all the fading begins at the same time. I tried adding some DelayTime actions in between but they don't seem have any effect. Any ideas?

//@interface OpaqueSprite: Sprite <CocosNodeOpacity>{}

		OpaqueSprite *head = [Sprite spriteWithFile:@"head.png"];
		OpaqueSprite *body = [Sprite spriteWithFile:@"body.png"];
		OpaqueSprite *limbs = [Sprite spriteWithFile:@"limbs.png"];

		[head setPosition:cpv(130, 160)];
		[body setPosition:cpv(350, 160)];
		[limbs setPosition:cpv(233, 195)];

		[self add:head z:1];
		[self add:body z:1];
		[self add:limbs z:1];

		id action1 = [FadeIn actionWithDuration:1.0f];
		id action2 = [FadeIn actionWithDuration:2.0f]; // each fade should take one second
		id action3 = [FadeIn actionWithDuration:3.0f];
//I'd like each sprite to take one second to fade in, but one at a time. 

		[Sequence actions: [head do: action1],
							[body do: action2],
							[limbs do: action3], nil];

Posted 2 years ago #

Codemattic
Moderator

Are you sure you want to have three OpaqueSprite objects in your OpaqueSprite class? Seems like it should be:

Sprite *head = [Sprite spriteWithFile:@"head.png"];
...

Maybe create an action for fadein with duration 1 sec for the first sprite. Then create a sequence action that has a delay action of 1 sec and then a fadein of 1 sec for the 2nd sprite. Then create a sequence action that has a delay of 2 secs and then a fadein of 1 sec for the 3rd sprite. Would that work? There could be an easier way - Im not sure - but thats the first thing I thought of. hth, Codemattic

Posted 2 years ago #

stu
Member

My OpaqueSprites inherit from Sprite so I think it should be ok.

I tried your suggestion but it didn't work as expected. (although the final limbs added blink and look like it fades out three times) Anyways thanks for your input, you're always helpful Codemattic!

id action1 = [FadeIn actionWithDuration:1.0f];

		id seq1= [Sequence actions:  action1, nil];
		id seq2= [Sequence actions: [DelayTime actionWithDuration:1], action1, nil];
		id seq3= [Sequence actions: [DelayTime actionWithDuration:2], action1, nil];

		[head do: seq1];
		[body do: seq2];
		[limbs do: seq3];

Posted 2 years ago #

Codemattic
Moderator

just for fun try:

id seq2= [Sequence actions: [DelayTime actionWithDuration:1], [FadeIn actionWithDuration:1.0f], nil];
id seq3= [Sequence actions: [DelayTime actionWithDuration:2], [FadeIn actionWithDuration:1.0f], nil];

Posted 2 years ago #

stu
Member

It was a lot of fun but no dice :( I think the problem is that I'm trying to animate multiple sprites concurrently. I've tried spawning some sequence of actions for each sprite to do but that didn't work either.

Posted 2 years ago #

Codemattic
Moderator

works for me. I modified SpritesTest:

tamara.opacity=0;
grossini.opacity=0;
id action1= [FadeIn actionWithDuration:1.0f];
id action2= [Sequence actions: [DelayTime actionWithDuration:1.0f], [FadeIn actionWithDuration:1.0f], nil];
[tamara runAction: action1];
[grossini runAction:action2];

tamara fadesin over a second and then grossini fadesin over a second.

Posted 2 years ago #

ob1
Member
Are you sure you don't start the actions several times ?

I had this mistake in my game loop with something like:
```
- step: (cctime) dt
{
 if (somecondition)
  {
     [tamara runAction: action1];

  }

}
```
This will restart the action from the beginning at each step. Also you cannot use the same action on several sprites, you have to copy it before adding it to the sprite.
Posted 2 years ago #
stu
Member
Ok figured it out. I think I should change my nick to Stupid Stu.
-Don't forget to set the opacity to zero before fading in. Duh.
```
-(void) setOpacity: (GLubyte) opacityValue
{
	opacity = opacityValue;
	// self.opacity = opacityValue; // doesn't work because it means [self setOpacity: opacityValue];

}
```
"Also you cannot use the same action on several sprites, you have to copy it before adding it to the sprite." - don't use the same fade action for multiple sprites.

Anyways thanks for all the help. I was pretty stuck but I learned a lot.

One more question I guess. Any idea why this works:
```
id fade = [FadeIn actionWithDuration:1.0f];
		id seq1= [Sequence actions: fade, nil];
```
but this doesn't? //error: expected ':' before ']' token
```
id seq1= [Sequence actions: [ [FadeIn actionWithDuration:1.0f], nil];
```
Posted 2 years ago #
Clain
Member

Because there's an extra [ right after actions: that shouldn't be there.

Posted 2 years ago #

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