Particle System as CCNode Child and Chipmunk Physics

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Particle System as CCNode Child and Chipmunk Physics

(5 posts) (3 voices)

Started 1 year ago by horseshoe7
Latest reply from horseshoe7

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horseshoe7
Member

Hi,
I'm working on something where discs slide around the screen, and I want to make it such that the user's most recent shot with one of these discs will have a trail behind it, using a CCParticleSystem.

I could use some help. I kept the particle system as a member of my Disc class (which itself inherits from CCNode). I thought that if I add the particle system as a child to my disc class, whenever I update the disc's position, the ParticleSystem will move with it.

As it so happens, the Chipmunk physics objects are placed in the right spot, but the disc objects as well as the Particle System are drawn at 0,0 and can't be changed.

If I comment out the initialisation of the Particle System everything works correctly.

So my question is how does one integrate a particleSystem into their code? The tests seem to be somewhat simple examples, because the particle system is a child of the Layer, and one changes the position of the emitter directly - I'm trying something a little bit (but not much?) more complicated.

At any rate, I'm finding this area of Cocos2D doesn't have too much documentation / tutorials associated with it and I'm not the most experienced programmer.

Any help would be appreciated.

Posted 1 year ago #
gaminghorror
Member

Do you update the disc's position with the chipmunk body position each frame? The node itself won't move magically, you have to sync the visual representation (node, sprite) with the physics body manually. Use a [self schedule:@selector(update:)] method and in -(void) update:ccTime(delta) {} update self.position with body's position.

Posted 1 year ago #
horseshoe7
Member

yes. the update function (the one that gets called every frame) will update the disc sprite position to its chipmunk body's position.

when i add a particle system as a child of the disc (at position 0,0 or the centre of the disc), then shouldn't it 'move with this disc' when i update the disc's position?

OR, do particle systems only work in world coordinates, i.e. that of the scene?

If I implement the particle system as a child of the scene and not of the disc, I can get it to follow along with the disc's position. I'll just have to write some more code to make that work in the generic case. Right now I have it working for one specific disc, where I need to make it be able to do it for any disc (if it meets certain conditions).

thanks

Posted 1 year ago #
mobilebros
Moderator

This sounds like a strange problem indeed..... I think something else besides the obvious is tripping you up. I've done something like this before with no problem, the only thing you might not like is that a trail might not be formed since the disc is a parent (I may be wrong with the newer versions)... but CCFollow is an action that is supposed to "follow" another node, it may come in handy.

Posted 1 year ago #
horseshoe7
Member

I worked around the issue, in that my moving discs keep a pointer to the particle system which i've set as a child of the main layer. so i update it that way and it works.

Posted 1 year ago #

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