addModifier(forProperties:at:modifier:)
Adds a block that modifies particle properties, to be executed each time SceneKit renders a frame.
Declaration
func addModifier(forProperties properties: [SCNParticleSystem.ParticleProperty], at stage: SCNParticleModifierStage, modifier block: @escaping SCNParticleModifierBlock)Parameters
- properties:
An array containing one or more of the constants listed in
Particle Property Keys, each of which specifies a property of the appearance or behaviors of particles in the particle system. - stage:
The stage of SceneKit’s particle simulation during which to call the block. See Scnparticlemodifierstage for allowed values.
- block:
A Scnparticlemodifierblock block to be called every time SceneKit renders a frame. In this block you can modify the properties of all particles in the system.
Discussion
By associating a block with one or more particle properties, you can run arbitrary code that modifies those properties during each frame of animation. This option provides maximum flexibility for changing the appearance or behavior of particles over time.