Table of Contents

Class GPUParticles2D

A 2D particle emitter.

Inheritance
GPUParticles2D

Remarks

2D particle node used to create a variety of particle systems and effects. GPUParticles2D features an emitter that generates some number of particles at a given rate.

Use the process_material property to add a ParticleProcessMaterial to configure particle appearance and behavior. Alternatively, you can add a ShaderMaterial which will be applied to all particles.

2D particles can optionally collide with LightOccluder2D, but they don't collide with PhysicsBody2D nodes.

See Also

Particle systems (2D)
2D Particles Demo
2D Dodge The Creeps Demo (uses GPUParticles2D for the trail behind the player)

Properties

amount

The number of particles to emit in one emission cycle. The effective emission rate is (amount * amount_ratio) / lifetime particles per second. Higher values will increase GPU requirements, even if not all particles are visible at a given time or if amount_ratio is decreased.

Note: Changing this value will cause the particle system to restart. To avoid this, change amount_ratio instead.

var amount : int = 8

Property Value

int

Remarks

  • void set_amount(int value)
  • int get_amount

amount_ratio

The ratio of particles that should actually be emitted. If set to a value lower than 1.0, this will set the amount of emitted particles throughout the lifetime to amount * amount_ratio. Unlike changing amount, changing amount_ratio while emitting does not affect already-emitted particles and doesn't cause the particle system to restart. amount_ratio can be used to create effects that make the number of emitted particles vary over time.

Note: Reducing the amount_ratio has no performance benefit, since resources need to be allocated and processed for the total amount of particles regardless of the amount_ratio. If you don't intend to change the number of particles emitted while the particles are emitting, make sure amount_ratio is set to 1 and change amount to your liking instead.

var amount_ratio : float = 1.0

Property Value

float

Remarks

  • void set_amount_ratio(float value)
  • float get_amount_ratio

collision_base_size

Multiplier for particle's collision radius. 1.0 corresponds to the size of the sprite. If particles appear to sink into the ground when colliding, increase this value. If particles appear to float when colliding, decrease this value. Only effective if collision_mode is ParticleProcessMaterial.COLLISION_RIGID or ParticleProcessMaterial.COLLISION_HIDE_ON_CONTACT.

Note: Particles always have a spherical collision shape.

var collision_base_size : float = 1.0

Property Value

float

Remarks

  • void set_collision_base_size(float value)
  • float get_collision_base_size

draw_order

Particle draw order. Uses DrawOrder values.

var draw_order : int = 1

Property Value

int

Remarks

  • void set_draw_order(int value)
  • int get_draw_order

emitting

If true, particles are being emitted. emitting can be used to start and stop particles from emitting. However, if one_shot is true setting emitting to true will not restart the emission cycle unless all active particles have finished processing. Use the finished signal to be notified once all active particles finish processing.

Note: For one_shot emitters, due to the particles being computed on the GPU, there may be a short period after receiving the finished signal during which setting this to true will not restart the emission cycle.

Tip: If your one_shot emitter needs to immediately restart emitting particles once finished signal is received, consider calling GPUParticles2D.restart instead of setting emitting.

var emitting : bool = true

Property Value

bool

Remarks

  • void set_emitting(bool value)
  • bool is_emitting

explosiveness

How rapidly particles in an emission cycle are emitted. If greater than 0, there will be a gap in emissions before the next cycle begins.

var explosiveness : float = 0.0

Property Value

float

Remarks

  • void set_explosiveness_ratio(float value)
  • float get_explosiveness_ratio

fixed_fps

The particle system's frame rate is fixed to a value. For example, changing the value to 2 will make the particles render at 2 frames per second. Note this does not slow down the simulation of the particle system itself.

var fixed_fps : int = 30

Property Value

int

Remarks

  • void set_fixed_fps(int value)
  • int get_fixed_fps

fract_delta

If true, results in fractional delta calculation which has a smoother particles display effect.

var fract_delta : bool = true

Property Value

bool

Remarks

  • void set_fractional_delta(bool value)
  • bool get_fractional_delta

interp_to_end

Causes all the particles in this node to interpolate towards the end of their lifetime.

Note: This only works when used with a ParticleProcessMaterial. It needs to be manually implemented for custom process shaders.

var interp_to_end : float = 0.0

Property Value

float

Remarks

  • void set_interp_to_end(float value)
  • float get_interp_to_end

interpolate

Enables particle interpolation, which makes the particle movement smoother when their fixed_fps is lower than the screen refresh rate.

var interpolate : bool = true

Property Value

bool

Remarks

  • void set_interpolate(bool value)
  • bool get_interpolate

lifetime

The amount of time each particle will exist (in seconds). The effective emission rate is (amount * amount_ratio) / lifetime particles per second.

var lifetime : float = 1.0

Property Value

float

Remarks

  • void set_lifetime(float value)
  • float get_lifetime

local_coords

If true, particles use the parent node's coordinate space (known as local coordinates). This will cause particles to move and rotate along the GPUParticles2D node (and its parents) when it is moved or rotated. If false, particles use global coordinates; they will not move or rotate along the GPUParticles2D node (and its parents) when it is moved or rotated.

var local_coords : bool = false

Property Value

bool

Remarks

  • void set_use_local_coordinates(bool value)
  • bool get_use_local_coordinates

one_shot

If true, only one emission cycle occurs. If set true during a cycle, emission will stop at the cycle's end.

var one_shot : bool = false

Property Value

bool

Remarks

  • void set_one_shot(bool value)
  • bool get_one_shot

preprocess

Particle system starts as if it had already run for this many seconds.

Note: This can be very expensive if set to a high number as it requires running the particle shader a number of times equal to the fixed_fps (or 30, if fixed_fps is 0) for every second. In extreme cases it can even lead to a GPU crash due to the volume of work done in a single frame.

var preprocess : float = 0.0

Property Value

float

Remarks

  • void set_pre_process_time(float value)
  • float get_pre_process_time

process_material

Material for processing particles. Can be a ParticleProcessMaterial or a ShaderMaterial.

var process_material : Material

Property Value

Material

Remarks

randomness

Emission lifetime randomness ratio.

var randomness : float = 0.0

Property Value

float

Remarks

  • void set_randomness_ratio(float value)
  • float get_randomness_ratio

seed

Sets the random seed used by the particle system. Only effective if use_fixed_seed is true.

var seed : int = 0

Property Value

int

Remarks

  • void set_seed(int value)
  • int get_seed

speed_scale

Particle system's running speed scaling ratio. A value of 0 can be used to pause the particles.

var speed_scale : float = 1.0

Property Value

float

Remarks

  • void set_speed_scale(float value)
  • float get_speed_scale

sub_emitter

Path to another GPUParticles2D node that will be used as a subemitter (see sub_emitter_mode). Subemitters can be used to achieve effects such as fireworks, sparks on collision, bubbles popping into water drops, and more.

Note: When sub_emitter is set, the target GPUParticles2D node will no longer emit particles on its own.

var sub_emitter : NodePath = NodePath("")

Property Value

NodePath

Remarks

texture

Particle texture. If null, particles will be squares with a size of 1×1 pixels.

Note: To use a flipbook texture, assign a new CanvasItemMaterial to the GPUParticles2D's material property, then enable particles_animation and set particles_anim_h_frames, particles_anim_v_frames, and particles_anim_loop to match the flipbook texture.

var texture : Texture2D

Property Value

Texture2D

Remarks

trail_enabled

If true, enables particle trails using a mesh skinning system.

Note: Unlike GPUParticles3D, the number of trail sections and subdivisions is set with the trail_sections and trail_section_subdivisions properties.

var trail_enabled : bool = false

Property Value

bool

Remarks

  • void set_trail_enabled(bool value)
  • bool is_trail_enabled

trail_lifetime

The amount of time the particle's trail should represent (in seconds). Only effective if trail_enabled is true.

var trail_lifetime : float = 0.3

Property Value

float

Remarks

  • void set_trail_lifetime(float value)
  • float get_trail_lifetime

trail_section_subdivisions

The number of subdivisions to use for the particle trail rendering. Higher values can result in smoother trail curves, at the cost of performance due to increased mesh complexity. See also trail_sections. Only effective if trail_enabled is true.

var trail_section_subdivisions : int = 4

Property Value

int

Remarks

  • void set_trail_section_subdivisions(int value)
  • int get_trail_section_subdivisions

trail_sections

The number of sections to use for the particle trail rendering. Higher values can result in smoother trail curves, at the cost of performance due to increased mesh complexity. See also trail_section_subdivisions. Only effective if trail_enabled is true.

var trail_sections : int = 8

Property Value

int

Remarks

  • void set_trail_sections(int value)
  • int get_trail_sections

use_fixed_seed

If true, particles will use the same seed for every simulation using the seed defined in seed. This is useful for situations where the visual outcome should be consistent across replays, for example when using Movie Maker mode.

var use_fixed_seed : bool = false

Property Value

bool

Remarks

  • void set_use_fixed_seed(bool value)
  • bool get_use_fixed_seed

visibility_rect

The Rect2 that determines the node's region which needs to be visible on screen for the particle system to be active.

Grow the rect if particles suddenly appear/disappear when the node enters/exits the screen. The Rect2 can be grown via code or with the Particles → Generate Visibility Rect editor tool.

var visibility_rect : Rect2 = Rect2(-100, -100, 200, 200)

Property Value

Rect2

Remarks

  • void set_visibility_rect(Rect2 value)
  • Rect2 get_visibility_rect

Methods

capture_rect

Qualifiers: const

Returns a rectangle containing the positions of all existing particles.

Note: When using threaded rendering this method synchronizes the rendering thread. Calling it often may have a negative impact on performance.

Rect2 capture_rect

convert_from_particles(Node)

Sets this node's properties to match a given CPUParticles2D node.

void convert_from_particles(Node particles)

Parameters

particles Node

emit_particle(Transform2D, Vector2, Color, Color, int)

Emits a single particle. Whether xform, velocity, color and custom are applied depends on the value of flags. See EmitFlags.

The default ParticleProcessMaterial will overwrite color and use the contents of custom as (rotation, age, animation, lifetime).

Note: GPUParticles2D.emit_particle is only supported on the Forward+ and Mobile rendering methods, not Compatibility.

void emit_particle(Transform2D xform, Vector2 velocity, Color color, Color custom, int flags)

Parameters

xform Transform2D
velocity Vector2
color Color
custom Color
flags int

request_particles_process(float)

Requests the particles to process for extra process time during a single frame.

Useful for particle playback, if used in combination with use_fixed_seed or by calling GPUParticles2D.restart with parameter keep_seed set to true.

void request_particles_process(float process_time)

Parameters

process_time float

restart(bool)

Restarts the particle emission cycle, clearing existing particles. To avoid particles vanishing from the viewport, wait for the finished signal before calling.

Note: The finished signal is only emitted by one_shot emitters.

If keep_seed is true, the current random seed will be preserved. Useful for seeking and playback.

void restart(bool keep_seed)

Parameters

keep_seed bool

Events

finished

Emitted when all active particles have finished processing. To immediately restart the emission cycle, call GPUParticles2D.restart.

This signal is never emitted when one_shot is disabled, as particles will be emitted and processed continuously.

Note: For one_shot emitters, due to the particles being computed on the GPU, there may be a short period after receiving the signal during which setting emitting to true will not restart the emission cycle. This delay is avoided by instead calling GPUParticles2D.restart.

signal finished