Properties
_enable
_enable: boolean = false
color
color: GradientRange = new GradientRange()
name
name: string = PARTICLE_MODULE_NAME.COLOR
needAnimate
needAnimate: Boolean = true
needUpdate
needUpdate: Boolean = false
target
target: IParticleSystemRenderer | null = null
颜色随时间变化的参数，各个 key 之间线性差值变化。