GPU Particles
Starting from Babylon.js v3.2, you can leverage a new WebGL2 feature, the transform feedback buffer, to drastically boost the performance of particles. Whereas regular particles use the CPU for animation and the GPU for rendering the new WebGL2 API allows Babylon.js to use the GPU for both animation and rendering. With GPU particles, everything is offloaded to the GPU.
Unfortunately this feature is only available when WebGL2 is available. You can use BABYLON.GPUParticleSystem.IsSupported to detect if GPU particles can be used. When they are supported, GPU particles can almost be used like regular particles:
var particleSystem = new BABYLON.GPUParticleSystem("particles", { capacity:1000000 }, scene);
As CPU is no longer involved, you can go crazy with active particles (1000000 in this example). Also, you can use particleSystem.activeParticleCount to define the number of active particle count if you want to limit the GPU usage.
Note: Sub emitters are not supported in GPU particles.
Random Texture
It is a shame but there is no good way to get random numbers when running on the GPU. To fill this gap, Babylon.js will create a texture filled with thousands of random values. These values will be read by the particle update shader to animate the particles. By default the biggest supported texture size is used (16K). You may want to reduce the size of this texture by initializing the system like this:
var particleSystem = new BABYLON.GPUParticleSystem("particles", { capacity:1000000, randomTextureSize: 4096 }, scene);
Fallback
As the GPUParticleSystem and the ParticleSystem share almost all their API, it is easy to switch from one to another when WebGL2 is not supported. Keep in mind that the CPU cannot animate as many particles as the GPU can. So you will probably have to reduce the capacity of your system when not using the GPUParticleSystem.
Stopping a GPU Particle System
When calling system.stop() on a GPUParticleSystem object, you will force the system to stop generating new particles. But particles will still be rendered even if not visible.
To completely stop a GPUParticleSystem, you have to call dispose() on it.
Using custom effects to render the particle system
New since 5.0, you can now use a custom effects with GPU particles!
GPU Particles with custom effect: GPU Particles with custom effect
Unsupported Features
The following features are not supported by GPU particles due to their inner nature:
- ManualEmitCount
- disposeOnStop
- Dual values per gradient (only one value is supported)
- Emit rate gradients are not supported
- Start size gradients are not supported
- Mesh emitter