Particle systems

The ParticleEmitter class derives from BillboardSet to implement a particle system that updates automatically.

The parameters of the particle system are stored in a ParticleEffect resource class, which uses XML format. Call SetEffect() to assign the effect resource to the emitter. Most of the parameters can take either a single value, or minimum and maximum values to allow for random variation. See below for all supported parameters:

<particleemitter>
    <material name="MaterialName" />
    <updateinvisible enable="true|false" />
    <relative enable="true|false" />
    <scaled enable="true|false" />
    <sorted enable="true|false" />
    <fixedscreensize enable="true|false" />
    <emittertype value="sphere|box" />
    <emittersize value="x y z" />
    <emitterradius value="x" />
    <direction min="x1 y1 z1" max="x2 y2 z2" />
    <constantforce value="x y z" />
    <dampingforce value="x" />
    <activetime value="t" />
    <inactivetime value="t" />
    <interval min="t1" max="t2" />
    <emissionrate min="t1" max="t2" />
    <particlesize min="x1 y1" max="x2 y2" />
    <timetolive min="t1" max="t2" />
    <velocity min="x1" max="x2" />
    <rotation min="x1" max="x2" />
    <rotationspeed min="x1" max="x2" />
    <sizedelta add="x" mul="y" />
    <color value="r g b a" />
    <colorfade color="r g b a" time="t" />
    <texanim uv="u1 v1 u2 v2" time="t" />
</particleemitter>

Notes:

• Zero active or inactive time period means infinite.
• Interval is the reciprocal of emission rate. Either can be used to define the rate at which new particles are emitted.
• Instead of defining a single color element, several colorfade elements can be defined in time order to describe how the particles change color over time.
• Use several texanim elements to define a texture animation for the particles.