Wallpaper Engine - Designer Documentation

# Particle Component - Emitters

The emitter of a particle system determines the way in which new particles are created. Your particle system needs at least one emitter to function.

There are three types of emitters:

  • Sphere random: Spawns particles in a circular sphere around the origin of your particle system.
  • Box random: Spawns particles in a rectangle around the origin of your particle system.
  • Layer image: Spawns particles based on an image layer, which includes standard textures, text layers and puppet warps.

The Sphere random and Box random emitter are largely the same, they simply offer a different shape in which the particles spawn. The Layer image emitter is an entirely unique emitter which is set up in a completely different way.

# Sphere random and Box random emitters

The sphere random emitter will spawn particles within a circle, while the box random emitter will spawn all particles within a rectangle. Their configuration is largely the same, though minor differences are noted where applicable.

# Offset

Defines an offset for each direction at which the particles spawn, relative to the particle system position.

# Directions

Defines the direction in which particles spawn around the origin of your particle system. A value of 1 represents the value of Distance Max that you can configure further down.

Setting Y to 2 would mean the height of the emitter is double the max distance. Setting it to 0 would mean the emitter has no height, all particles spawn in a straight horizontal line. The same logic applies to X in respect to horizontal values and Z for depth values (in 3D wallpapers).

# Sign (Sphere Random Emitter)

This setting allows you to force positive or negative values for the spawn location of your particles for the given axis. Valid values are:

  • 0: Default, both positive and negative values are possible.
  • 1: Only positive values are possible.
  • -1: Only negative values are possible.

For example: By setting X to -1, all X values will be negative, meaning the particles will spawn to the left of the particle system only. See the following visualization with different X / Y combinations in the upper left corner:

# Distance Min

The minimum distance at which particles spawn from the center of the particle system.

# Distance Max

The maximum distance at which particles spawn from the center of the particle system. You can further tweak this value by adjusting the multiplier in the Directions option above.

# Control point

Allows you to attach the emitter position to a control point. See the Control point section for more details.

# Rate

The number of particles that spawn per second. The maximum number of particles is defined in the System settings of the particle system.

# Instantaneous

The number of particles which are created instantly when the particle system is created. If you set a value here while Rate is set to 0, the particle system will only spawn particles once and then cease to exist, making it especially useful for child particle systems and one-time uses of particles.

# Duration

The lifetime of the emitter in seconds. The default value of 0 means the emitter will never disappear. A value of 10 means the emitter will stop emitting new particles after 10 seconds but existing particles will continue to exist until they disappear according to their setup.

You can restart the emitter only by restarting the entire particle system via SceneScript. You can invoke the stop() and play() functions on your particle system via SceneScript if needed for your custom needs.

Please note

In the Wallpaper Engine editor, the particle system will always be visible indefinitely, you can only visualize this when applying and previewing the wallpaper.

# Delay

Allows you to add delay the start of the particle emitter by a given number of seconds.

# Limit to one per frame

When enabled, the emitter only spawns one particle per frame. This means that the FPS limit configured by the user may have an impact on the number of particles.

Please note

This option may be needed in conjunction with the Rope renderer. If your particle system spawns multiple particles during a single frame on top of each other, it will create artifacts in the rope effect. You may avoid this by limiting the particle spawn rate based on the FPS.

# Random periodic emission

When enabled, the emitter will periodically stop and restart the emission of new particles. It can be further tweaked with the following settings:

  • Min periodic duration: The minimum time that particles are emitted before stopping temporarily.
  • Max periodic duration: The maximum time that particles are emitted before stopping temporarily.
  • Min periodic delay: The minimum time between emissions.
  • Max periodic delay: The maximum time between emissions.

# Speed Min

The minimum particle speed in conjunction with a movement Operator.

# Speed Max

The maximum particle speed in conjunction with a movement Operator.

# Audio response

Setting this to Center means that the particle system will be audio responsive to the left and right audio channel at the same time. The emitter will only be active when audio is playing.

# Exponent

Exponential power of the audio response to bias the response towards lower or higher values. By increasing this value, you will reduce how strongly low audio volume will affect the emitter.

# Bounds

The bounds control at what points the audio response starts and stops. If the audio bounds are configured to be 0 and 1, then the audio effect will slowly fade. A more sudden effect can be achieved by making the bounds more narrow. For example, if you set the audio bounds to 0.8 and 1, the audio responsiveness will only take effect for volume levels between 0.8 and 1 which makes the audio effect more sudden and limits it to the upper range of volume levels.

# Frequency max

The highest audio frequency that the effect reacts to. The values go from 0 to 15, where 0 is bass sounds and 15 higher frequency treble sounds. For example, set this to 1 if you want the emitter to only react to the beat of music being played (as the beat is usually reflected by lower bass frequencies).

# Frequency min

The lowest audio frequency that the effect reacts to. The values go from 0 to 15, where 0 is bass sounds and 15 higher frequency treble sounds. For example, set this to 0 if you want the emitter to only react to the beat of music being played (as the beat is usually reflected by lower bass frequencies).

# Layer image emitter

The layer image emitter is a special emitter which allows you to tie an image layer to your particle system and use it to spawn particles based on the image that is being used. This also includes text layers like clocks and more advanced image layers like puppet warps. It shares many settings with the other emitters which are described above, this section focuses on the settings which are unique to the layer image emitter.

  • Copy layer color: Colors the particles according to the color of your image layer at their spawn point.
  • Update emission bitmap periodically: When enabled, Wallpaper Engine will regularly check if the image has changed and update the particle spawn points accordingly. This is really only necessary when your texture regularly changes, for example in text layers showing clocks. This is not needed for animated puppet warps or other types of layer animations and should be kept disabled to conserve system performance.
  • Inherit layer motion: Applies any motion of the layer to your particles as well. Let's you define a minimum and maximum speed.
  • Random offset: Adds a minimum and maximum positional offset to the particles if you don't want their spawn point to be precisely where your image is.

The other settings are the same as outlined for the box and sphere emitters in the section above.

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