Question about particles « cocos2d for iPhone

Question about particles

(2 posts) (2 voices)

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ob1
Member

I started making effects with particle and my designer often as remarks like "very good but twice as fast and half the size".

As far as I know I cannot just reduce the size or augment the speed of the "emitter". For example, the total duration of a system is probably emitter.duration + emitter.life.

To change the size of the effect you also need to change emitter.life and emitter.speed I guess.

And changing any of those parameters changes the other and the "shape" of the effect too as a side effect.

So I have the following questions:

- Is there an easy way to have a "speed" factor or a "zoom" factor on an emitter?
- If not, would it be possible to code such functions?
- If not, are there any rule of thumbs or formulas to change the speed or size of an emitter while preserving the shape of an effect ?

Posted 2 years ago #

riq
Key Master

another way to do it, is by adding a scaleTime property.

eg:

-(void) step: (ccTime) dt_old
{
    float dt = dt_old * scaleTime;

    // ....
    // ....
}

scaleTime should be a property, and you will be able to modify it by:

emitter.scaleTime = 0.1f; // very slow
emitter.scaleTime = 1.0f; // normal speed
emitter.scaleTime = 10;   // 10 times faster

Posted 2 years ago #

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