Struct CAEmitterCellBuilder 

pub struct CAEmitterCellBuilder { /* private fields */ }

Builder for a particle type.

Used via CAEmitterLayerBuilder::particle(|p| p.birth_rate(...)).

Implementations

impl CAEmitterCellBuilder

pub fn new() -> Self

Create a new cell builder with default values.

pub fn birth_rate(self, rate: f32) -> Self

Set the number of particles spawned per second.

pub fn lifetime(self, seconds: f32) -> Self

Set how long each particle lives (in seconds).

pub fn lifetime_range(self, range: f32) -> Self

Set random variation in lifetime (+/- seconds).

pub fn velocity(self, v: f64) -> Self

Set initial velocity (points per second).

pub fn velocity_range(self, range: f64) -> Self

Set random variation in velocity.

pub fn emission_longitude(self, radians: f64) -> Self

Set the direction of emission (radians, 0 = right, PI/2 = up).

pub fn emission_toward(self, from: (f64, f64), target: (f64, f64)) -> Self

Set emission direction to point toward a target position.

The from parameter is the emitter position.

pub fn emission_range(self, radians: f64) -> Self

Set the spread of emission (radians).

Use PI * 2.0 for emission in all directions (360°). Use PI / 6.0 for a 30° spread.

pub fn scale(self, s: f64) -> Self

Set the scale of particles (1.0 = original size).

pub fn scale_range(self, range: f64) -> Self

Set random variation in scale.

pub fn scale_speed(self, speed: f64) -> Self

Set rate of scale change per second.

pub fn alpha_speed(self, speed: f32) -> Self

Set rate of alpha change per second (negative = fade out).

pub fn spin(self, radians_per_sec: f64) -> Self

Set rotation speed (radians per second).

pub fn spin_range(self, range: f64) -> Self

Set random variation in spin.

pub fn acceleration(self, x: f64, y: f64) -> Self

Set acceleration (points per second squared).

Use negative y for gravity effect.

pub fn color(self, color: impl Into<Color>) -> Self

Set particle color using a Color value.

Example

.color(Color::RED)
.color(Color::rgb(0.3, 0.8, 1.0))
.color(Color::WHITE.with_alpha(0.5))

pub fn color_rgb(self, r: f64, g: f64, b: f64) -> Self

Set particle color (RGB, 0.0-1.0).

pub fn color_rgba(self, r: f64, g: f64, b: f64, a: f64) -> Self

Set particle color (RGBA, 0.0-1.0).

pub fn image(self, img: ParticleImage) -> Self

Set the particle image.

pub fn build(self) -> Retained<CAEmitterCell>

Build the CAEmitterCell.

Trait Implementations

impl Default for CAEmitterCellBuilder

fn default() -> Self

Returns the “default value” for a type.