anchor.diff:  <a| emission rate
   a| `setParticlesPerSec()`
   a| 20
  -a| Density of the effect, how many new particles are emitted per second. +Set to zero to control the start/end of the effect. +Set to a number for a constantly running effect.
  +a| Density of the effect, how many new particles are emitted per second. +
  +Set to zero to control the start/end of the effect. +
  +Set to a number for a constantly running effect.
   
   <a| size
   a| `setStartSize()`, `setEndSize()`
   a| 0.2f, 2f
  -a| The radius of the scaled sprite image. Set both to same value for constant size effect. +Set to different values for shrink/grow effect.
  +a| The radius of the scaled sprite image. Set both to same value for constant size effect. +
  +Set to different values for shrink/grow effect.
   
   <a| color
   a| `setStartColor()`, `setEndColor()`
   a| gray
  -a| Controls how the opaque (non-black) parts of the texture are colorized. +Set both to the same color for single-colored effects (e.g. fog, debris). +Set both to different colors for a gradient effect (e.g. fire).
  +a| Controls how the opaque (non-black) parts of the texture are colorized. +
  +Set both to the same color for single-colored effects (e.g. fog, debris). +
  +Set both to different colors for a gradient effect (e.g. fire).
   
   <a| direction/velocity
   a| `getParticleInfluencer(). setInitialVelocity(initialVelocity)`
  
positive.code: ----
  
  .  Trigger the effect by calling
  [source,java]
  ----
  explosion.emitAllParticles()
  ----
  
  .  End the effect by calling
  [source,java]
  ----
  explosion.killAllParticles()
  
negative.code: <a| fanning out
  a| `getParticleInfluencer(). setVelocityVariation(variation)`
  a| 0.2f
  a| How much the direction (`setInitialVelocity()`) can vary among particles. Use a value between 1 and 0 to create a directed swarm-like cloud of particles. +
  1 = Maximum variation, particles emit in random 360° directions (e.g. explosion, butterflies). +
  0.5f = particles are emitted within 180° of the initial direction. +
  0 = No variation, particles fly in a straight line in direction of start velocity (e.g. lasergun blasts).
  
  a| direction +
  (pick one)
  a| `setFacingVelocity()`
  a| false
  a| true = Flying particles pitch in the direction they're flying (e.g. missiles). +
  false = Particles keep flying rotated the way they started (e.g. debris).
  
  a| direction +
  (pick one)
  a| `setFaceNormal()`
  a| Vector3f.NAN
  a| Vector3f = Flying particles face in the given direction (e.g. horizontal shockwave faces up = Vector3f.UNIT_Y). +
  Vector3f.NAN = Flying particles face the camera.
  
  <a| lifetime
  a| `setLowLife()`, `setHighLife()`
  