Dynamically switching post-processing shaders

[Pietrek14]

In my game I need to apply a post-processing effect when the player uses a power-up. I based my post-processing around the official example from the Bevy repository. Is it possible to switch shaders during runtime / turn them on/off?

[wilk10]

Yes, it should be possible.

In the example there's the post_processing_pass_layer component that is used to mark the Camera2dBundle and MaterialMesh2dBundle.

If you want to apply a different effect, you'll need different materials (just another type different than PostprocessingMaterial in the example, that derives AsBindGroup and implements Material2d, pointing to the correct shader).

You'll also need multiple entities with different MaterialMesh2dBundles, one for each material (one material per effect).

When it's time to apply a different effect, despawn the entity with the the MaterialMesh2dBundle that is currently applied, and spawn a new entity with the new material for the new effect + add the post_processing_pass_layer component (or alternatively remove the current MaterialMesh2dBundle and insert the new material bundle into the same entity).

I think it should work, but let me know if it doesn't. Good luck!

[superdump]

I was going to suggest removing one material component from the mesh entity and adding another instead.

[wilk10]

Ah yes of course, I didn't think about that. That should work too

[Pietrek14]

Thanks man, works like a charm. I actually had to reset the whole entity cause the material component is a generic, but after a long fight I finally got it to work.