Particle system: adjust global speed

Astra · December 20, 2022, 3:24pm

Hey, recently I was looking for the possibility of speeding up a particlesystem in playcanvas globally. That is: making everything move faster or slower in the particle animation. Both how fast the particles move, how frequent they spawn, texture animation speed, etc. Values like particle lifetime would need to be scaled inversely to this.

I couldn’t find an easy way of doing this. Anyone know if that exists?
If not, I think it might be neat to have this as a feature, since doing this manually is pretty cumbersome.

Just to clarify: basically what I’m looking for is the effect of adding a multiplier to “dt” in update() if the particle system was written entirely in a custom script

Leonidas · December 20, 2022, 5:17pm

Hi @Astra,

That’s an interesting suggestion. Most likely it’s not doable so it may be a good feature request for the engine repo.

You can always try and patch the PlayCanvas engine, I think the particlesystem system onUpdate can be a good starting point:

github.com

playcanvas/engine/blob/96141aad3a19b4d3744a14c4f5198f4416a018d2/src/framework/components/particle-system/system.js#L203

      
        
                    } else {
                        if (sourceProp !== null && sourceProp !== undefined) {
                            data[prop] = sourceProp;
                        }
                    }
                }
            
            
    return this.addComponent(clone, data);
            }
            
            
onUpdate(dt) {
                const components = this.store;
                let numSteps;
                const stats = this.app.stats.particles;
            
            
    for (const id in components) {
                    if (components.hasOwnProperty(id)) {
                        const component = components[id];
                        const entity = component.entity;
                        const data = component.data;

yaustar · December 20, 2022, 5:22pm

It’s one of those use cases where it’s not very common (this is the first I’ve heard of someone needing this) so its less likely to be added to the engine.

Patching the update would be your best bet going forward

Marks · December 20, 2022, 5:47pm

I guess something like this makes sense in a game where the protagonist have time powers and can make everything go slower(or faster?) in relation to himself.

Astra · December 21, 2022, 8:11am

Thanks!
I’ll try that

Astra · December 21, 2022, 8:16am

yeah,
actually in our case it was just that the particle effect was part of a larger animation, that we wanted to be able to play at different speeds depending on the situation.