修改Velocity over Lifetime

修改Velocity over Lifetime,但是Unity并没有提供直接修改Velocity over Lifetime的方法，我们需要手动修改每个存在的粒子的速度。

void LateUpdate (){ParticleSystem.Particle[] particles = new ParticleSystem.Particle[particleSystem.particleCount];int count = particleSystem.GetParticles(particles);for(int i = 0; i < count; i++){particles[i].velocity = new Vector3(0, speed, 0);}particleSystem.SetParticles(particles, count);}