Particles Module

Tiny supports a subset of the particle workflows available in Unity. This subset is referred to as the Particles module. This document provides common use cases, examples, and a reference of Particles components.

See this module's API documentation for more information

Use Cases and Examples

This section demonstrates how to use the Particles module through common use cases and usage examples. If a use case or an example is similar to a topic in the Unity User Manual, a link is provided to the appropriate topic.

Simple Particle System

  1. Create a Sprite2D entity. This will be your proto-particle.
  2. Create an entity.
    1. Add a ParticleEmitter component.
    2. Set the particle property to the Sprite2D entity.
    3. Add a EmitterBoxSource component.

Modify the ParticleEmitter or the EmitterBoxSource properties to affect the emission (e.g. emission rate).

Spawn particles with initial modifiers

After adding a particle system, it is easy to control the state of newly created particles. From the ParticleEmitter component, you can add a related component using the + button.

  1. Add a EmitterInitialScale component to set the scale of each particle on emission.
  2. Add a EmitterInitialRotation component to set the rotation around the z-axis of each particle on emission.
  3. Add a EmitterInitialVelocity component to set the velocity (direction and speed) of each particle on emission.

For each of these components, it is possible to define the upper and lower bounds for the value; the actual value varies randomly between those bounds.

Spawn particles with changes over time

After adding a particle system, it is easy to specify the particle's changes over time. From the ParticleEmitter component, you can add a related component using the + button. Using a change over time component will most likely override any initial value component you provided.

Changing the color and alpha over time.

  1. Create an empty entity and name it ColorOverTimeKeys.
    1. Add a component KeyColor. The component holds the list of Color keyframes for the interpolation.
    2. Add two keys and set time 0.0 for the first one and 1.0 for the second one. Set different color/alpha values for both keys.
  2. Create an empty entity and name it ColorOverTimeCurve.
    1. Add a component LinearCurveColor.
    2. Drag and drop entity ColorOverTimeKeys into keys field.
  3. Select an emitter entity.
    1. Add a LifetimeColor component to the particle system entity in order to change the particle's color over time.
    2. Drag and drop ColorOverTimeCurve entity to curve field in LifetimeColor component.

Changing the speed over time.

  1. Create an empty entity and name it SpeedMultiplierOverTimeKeys.
    1. Add a component KeyFloat. The component holds the list of Float keyframes for the interpolation.
    2. Add two keys and set time 0.0 for the first one and 1.0 for the second one. Set speed to 5.0 for the first key and leave 0.0 fot the second.
  2. Create an empty entity and name it SpeedMultiplierOverTimeCurve.
    1. Add a component LinearCurveFloat.
    2. Drag and drop entity SpeedMultiplierOverTimeKeys into keys field.
  3. Select an emitter entity.
    1. Add a LifetimeSpeedMultiplier component to the particle system entity in order to change the particle's speed over time.
    2. Drag and drop SpeedMultiplierOverTimeCurve entity to curve field in LifetimeSpeedMultiplier component.

Components

Tiny is built around small, lightweight components. This way you only pay for what you need. This design usually creates more component types to represent data held in a single Unity component, which can be confusing at first for some developers.

Use this table to associate familiar Unity concepts with Tiny.

Unity Particle System Module Particles Components
Emission, Shape EmitterBoxSource, EmitterCircleSource, EmitterConeSource
Color Over Lifetime LifetimeColor
Rotation Over Lifetime LifetimeAngularVelocity
Size Over Lifetime LifetimeScale
Velocity Over Lifetime LifetimeVelocity, LifetimeSpeedMultiplier
Particle System Main module ParticleEmitter
Unity Particle System Property Particles Components
3D Start Rotation, Start Rotation EmitterInitialRotation, [EmitterInitialAngularVelocity][#emitterinitialangularvelocity]
Start Size EmitterInitialScale
Start Speed EmitterInitialVelocity

EmitterBoxSource

Change the Shape of emission to a Box with defined position and scale. Particles will be emitted from a random spot inside the box. The rect will be centered around the emitter's position.

Defaults the emission Rate over Time (number of particles emitted per unit of time) to 10.

Property Description
rect The region of the entity to use as the box emitter source. The position is set with the x and y values. The scaling is set with the width and height. Defaults width and height to 50.
attachToEmitter Sets whether the emitted particle's transform will be a child of this emitter.
If true, the emission position is set as the entity's local position, and the particle will be added as a transform child.
If false, the emitter's world position will be added to the emission position, and that result is set as the local position.

EmitterCircleSource

Change the Shape of emission to a Circle with defined radius and speed. Particles will be emitted from a random spot inside the circle with the random speed.

Property Description
radius Radius of the emitter
speed Initial speed of the particles.
speedBasedOnRadius If true, the initial speed is based on the initial particle's distance from the center of the emitter.

EmitterConeSource

Change the Shape of emission to a cone with defined radius, angle, and speed. Particles will be emitted from a random spot inside the base of the cone with the random speed and angle.

Property Description
radius The radius of the base of the cone
angle The angle of the cone
speed Initial speed of the particles.

EmitterInitialRotation

Sets the initial angle of each particle on emission.

Since the particle system is only in 2D coordinates as of right now, the angle is around the z-axis.

Property Description
angle The initial rotation angle in degrees of each particle around the z-axis. If the start and end values are the same, the initial rotation is constant. Otherwise, the rotation is a random value between the start and end values.

EmitterInitialScale

Sets the initial scale of each particle on emission.

Property Description
scale The initial scale of each particle. Defaults to 1. If the start and end values are the same, the initial scale is constant. Otherwise, the scale is a random value between the start and end values.

EmitterInitialVelocity

Sets the initial velocity of each particle on emission. The length of the velocity vector stands for the initial speed of the particle.

Property Description
velocity The initial emission velocity of each particle from the chosen emission position.

LifetimeColor

Specifies how a particle's color changes over its lifetime. It modifies the Sprite2DRenderer's color.

Property Description
curve A curve which defines the particle's color over its lifetime. In this case, the curve is a visual representation of a colour progression, which simply shows the main colours (which are called stops) and all the intermediate shades between them.

LifetimeAngularVelocity

  • Requires: ParticleEmitter

    Specifies how a particle's angular velocity changes over its lifetime. It modifies the Transform's local rotation.

This component uses angular velocity in the editor and explicit rotation values in the runtime. In Unity, the rotation over lifetime indicates an angular velocity in degrees per second whereas in Tiny, the LifetimeRotation indicates the actual rotation value used at time x.

Property Description
curve A curve which defines the particle's angular velocity in degrees around the z-axis over its lifetime. In this case, the curve is a line graph that sets the angular velocity over time.

LifetimeScale

Specifies how a particle's scale changes over its lifetime. It modifies the Transform's scale with a uniform scale (on x, y, z axis).

Property Description
curve A curve which defines how the particle's scale changes over its lifetime. In this case, the curve is a line graph that sets the scale over time.

LifetimeVelocity

Specifies how a particle's velocity (direction and speed) changes over its lifetime.

Property Description
curve A curve which defines how the particle's velocity changes over its lifetime. The net velocity used for modyfying the particle's position is calculated by adding the initial velocity and the velocity over time.

BurstEmission

An emitter with this component emits particles in bursts. A burst is a particle event where a number of particles are all emitted at the same time. A cycle is a single occurrence of a burst.

Property Description
count How many particles in every cycle.
interval The interval between cycles, in seconds.
cycles How many times to play the burst

ParticleEmitter

This is the core particle emitter component. When added to an entity, it becomes an emitter with given characteristics. The system continuously emits particles (loop). It is linked to the source data, the initial values and the lifetime values for particles. It contains global properties that affect the whole system (e.g. lifetime property). Various particle modifiers after initial emit can be added as component (e.g. EmitterInitialScale).

The Unity Prewarm's property is enabled if the prewarmPercent is equal or more than 0.5.

Property Description
particle The UTiny entity attached to the particle system and rendered in run-time. This proto-particle is used as a template.
maxParticles The maximum number of particles in the system at once. If the limit is reached, some particles are removed. Defaults to 1000.
emitRate The number of particles emitted per second. Defaults to 10.
lifetime The lifetime of each particle in seconds. Defaults start (min) and end (max) to 5.
attachToEmitter If true, then newly spawned particles will be children of the emitter.

Systems

ParticleSystem

  • Updates Before: Shared.InputFence, Shared.RenderingFence

The main entry system for particles. Spawns particles with given initial characteristics and updates particles' properties (scale, color, alpha, rotation) over time.

See this module's API documentation for more information