Particle System File Format (.kglp)
Simulant uses a custom file format to define particle system properties. These files are JSON files with a particular set of keys and values.
The JSON file should have a root dictionary which defines the particle system, it can have the following properties:
- name (string): This is a human readable description for the particle system
- quota (integer): This is the maximum number of live particles that the particle system can create across all emitters
- particle_width (float): This is the width of the particle sprites in world units
- particle_height (float): This is the height of the particle sprites in world units
- cull_each (boolean): If true each particle will be individually culled (not yet implemented)
- emitters (array): A list of dictionaries, each defining the properties of a particle emitter
- manipulators (array): A list of dictionaries, each defining a rule that affects particles each frame
- material (string): Either a path to a material file, or the name of a built-in material (e.g.
- material.XXXXX: These keys allow you to set individual material properties on the specified material, their type depends on the property type of the Material property.
- type (string): This is the type of emitter the valid options are "point" or "box"
- direction (string): This is the (relative) direction the particles travel. It's a space separated list of x, y, z floats.
- velocity (float): This is the speed at which particles are emitted
- ttl_min (float): The minimum time in seconds that a particle lives
- ttl_max (float): The maximum time in seconds that a particle lives
- angle (float): The angle in degrees from the direction vector that the particle can travel. The greater the angle, the more the particle spread
- colour (string): The colour of the particles emitted. This is a space separated list of r, g, b and alpha values (between 0.0 and 1.0)
- emission_rate (integer): A many particles can be emitted per second
- duration (float): How long in seconds that the emitter should last. Zero means forever
- repeat_delay (float): If set, the emitter will restart it's duration after this many seconds (e.g. repeated bursts of particles)
- type (string): The type of the affector, valid options are:
Additional properties depend on the type of the affector
- rate (float): A value between -1.0 and +1.0, the amount per second to reduce the size of the particle
- curve (string): This can be used instead of rate to use a curve function for the sizing. Options are linear(rate), or bell(peak, deviation).
- colours(array): A list of strings in the format "R G B A" or "R G B" where each element is a floating point number between 0.0 and 1.0
- interpolate(bool): Whether or not to blend between colours