Enum VertexEffect 

pub enum VertexEffect {
    Rotate {
        speed: f32,
    },
    Wobble {
        frequency: f32,
        amplitude: f32,
    },
    Pulse {
        frequency: f32,
        amplitude: f32,
    },
    Wave {
        direction: Vec3,
        frequency: f32,
        speed: f32,
        amplitude: f32,
    },
    Jitter {
        amplitude: f32,
    },
    StretchToVelocity {
        max_stretch: f32,
    },
    ScaleByDistance {
        center: Vec3,
        min_scale: f32,
        max_scale: f32,
        max_distance: f32,
    },
    FadeByDistance {
        near: f32,
        far: f32,
    },
    BillboardCylindrical {
        axis: Vec3,
    },
    BillboardFixed {
        forward: Vec3,
        up: Vec3,
    },
    FacePoint {
        target: Vec3,
    },
    Orbit {
        center: Vec3,
        speed: f32,
        radius: f32,
        axis: Vec3,
    },
    Spiral {
        center: Vec3,
        speed: f32,
        expansion: f32,
        vertical_speed: f32,
    },
    Sway {
        frequency: f32,
        amplitude: f32,
        axis: Vec3,
    },
    ScaleBySpeed {
        min_scale: f32,
        max_scale: f32,
        max_speed: f32,
    },
    Squash {
        axis: Vec3,
        amount: f32,
    },
    Tumble {
        speed: f32,
    },
    Attract {
        target: Vec3,
        strength: f32,
        max_displacement: f32,
    },
    Repel {
        source: Vec3,
        strength: f32,
        radius: f32,
    },
    Turbulence {
        frequency: f32,
        amplitude: f32,
        speed: f32,
    },
    ScaleByAge {
        start_scale: f32,
        end_scale: f32,
        lifetime: f32,
    },
    FadeByAge {
        start_alpha: f32,
        end_alpha: f32,
        lifetime: f32,
    },
    Vortex {
        center: Vec3,
        speed: f32,
        pull: f32,
        radius: f32,
    },
    Bounce {
        height: f32,
        frequency: f32,
        damping: f32,
    },
    Figure8 {
        width: f32,
        height: f32,
        speed: f32,
        ratio: f32,
    },
    Helix {
        axis: Vec3,
        radius: f32,
        speed: f32,
        progression: f32,
    },
    Flutter {
        intensity: f32,
        speed: f32,
    },
    Brownian {
        intensity: f32,
        speed: f32,
    },
}

Vertex shader effects for particle rendering.

Pre-built, composable effects that modify particle vertex transformations. Effects stack together and generate optimized WGSL code. Use these instead of raw crate::Simulation::with_vertex_shader for common effects.

Example

Simulation::<Ball>::new()
    .with_vertex_effect(VertexEffect::Rotate { speed: 2.0 })
    .with_vertex_effect(VertexEffect::Wobble {
        frequency: 3.0,
        amplitude: 0.05,
    })
    .with_vertex_effect(VertexEffect::Pulse {
        frequency: 4.0,
        amplitude: 0.3,
    })
    .run();

Effects are applied in order and compose naturally.

Variants

Rotate

Rotate particles around their facing axis.

Each particle spins at the specified speed, with a per-particle phase offset based on instance index for variety.

Fields

speed: f32

Rotation speed in radians per second.

Wobble

Wobble particles with sinusoidal position offset.

Creates a gentle floating/swaying motion.

Fields

frequency: f32

Oscillation frequency (higher = faster wobble).

amplitude: f32

Maximum offset distance.

Pulse

Pulse particle size over time.

Particles grow and shrink rhythmically.

Fields

frequency: f32

Pulse frequency (higher = faster pulsing).

amplitude: f32

Pulse amplitude (0.3 = +/- 30% size variation).

Wave

Wave effect coordinated across particles.

Creates a wave pattern that travels through the particle field.

Fields

direction: Vec3

Wave direction (normalized).

frequency: f32

Wave frequency (spatial).

speed: f32

Wave speed (temporal).

amplitude: f32

Wave amplitude (offset distance).

Jitter

Random per-frame jitter/shake.

Adds noise-like motion to particles.

Fields

amplitude: f32

Maximum jitter offset.

StretchToVelocity

Stretch particles in their velocity direction.

Requires velocity data passed to vertex shader. Note: This is a visual hint only - actual velocity stretching requires velocity in the vertex attributes.

Fields

max_stretch: f32

Maximum stretch multiplier.

ScaleByDistance

Scale particles based on distance from a point.

Particles closer to the point are larger.

Fields

center: Vec3

Center point.

min_scale: f32

Scale at center (closest).

max_scale: f32

Scale at max_distance (farthest).

max_distance: f32

Distance at which max_scale is reached.

FadeByDistance

Fade particles based on distance from camera/origin.

Modifies alpha based on distance for depth-based fading.

Fields

near: f32

Distance at which particles are fully visible.

far: f32

Distance at which particles are fully transparent.

BillboardCylindrical

Cylindrical billboarding - rotate only around one axis.

Useful for grass, trees, flames - things that should stay upright but still face the camera horizontally.

Fields

axis: Vec3

The axis to stay fixed (typically Y for upright sprites).

BillboardFixed

Fixed orientation - disable billboarding entirely.

Particles maintain a fixed orientation in world space. Useful for debris, leaves, or when combined with Rotate for tumbling.

Fields

forward: Vec3

Forward direction of the quad in world space.

up: Vec3

Up direction of the quad in world space.

FacePoint

Orient particles to face a specific point.

All particles rotate to look at the target point.

Fields

target: Vec3

The point all particles should face toward.

Orbit

Orbit particles around a center point.

Creates circular motion around a specified axis.

Fields

center: Vec3

Center point of the orbit.

speed: f32

Orbit speed in radians per second.

radius: f32

Orbit radius.

axis: Vec3

Axis of rotation (normalized).

Spiral

Spiral particles outward or inward.

Creates expanding or contracting spiral motion.

Fields

center: Vec3

Center point of the spiral.

speed: f32

Rotation speed in radians per second.

expansion: f32

Expansion rate (positive = outward, negative = inward).

vertical_speed: f32

Vertical speed (for 3D spirals).

Sway

Sway particles like grass or trees.

Creates a natural swaying motion anchored at the base.

Fields

frequency: f32

Sway frequency.

amplitude: f32

Maximum sway amplitude.

axis: Vec3

Sway axis (typically horizontal).

ScaleBySpeed

Scale particles based on their speed.

Faster particles appear larger or smaller.

Fields

min_scale: f32

Scale at zero speed.

max_scale: f32

Scale at max speed.

max_speed: f32

Speed at which max_scale is reached.

Squash

Squash/flatten particles along an axis.

Creates a flattened appearance, good for impact effects.

Fields

axis: Vec3

Axis to squash along.

amount: f32

Squash amount (0 = flat, 1 = normal).

Tumble

Tumble particles with random 3D rotation.

Creates chaotic spinning in all directions.

Fields

speed: f32

Rotation speed multiplier.

Attract

Attract particles toward a point.

Pulls particles closer to the target.

Fields

target: Vec3

Attraction target point.

strength: f32

Attraction strength.

max_displacement: f32

Maximum displacement.

Repel

Repel particles away from a point.

Pushes particles away from the source.

Fields

source: Vec3

Repulsion source point.

strength: f32

Repulsion strength.

radius: f32

Effect radius (no effect beyond this).

Turbulence

Turbulence/noise-based displacement.

Creates organic, chaotic motion using noise.

Fields

frequency: f32

Noise frequency (higher = more detail).

amplitude: f32

Displacement amplitude.

speed: f32

Animation speed.

ScaleByAge

Scale particles over their lifetime.

Particles grow or shrink as they age (approximated).

Fields

start_scale: f32

Scale at birth.

end_scale: f32

Scale at end of life.

lifetime: f32

Lifetime duration in seconds.

FadeByAge

Fade particles over their lifetime.

Particles become transparent as they age.

Fields

start_alpha: f32

Alpha at birth.

end_alpha: f32

Alpha at end of life.

lifetime: f32

Lifetime duration in seconds.

Vortex

Vortex/tornado effect - orbit with vertical pull.

Creates a whirlpool or tornado-like motion.

Fields

center: Vec3

Center point of the vortex.

speed: f32

Rotation speed in radians per second.

pull: f32

Vertical pull strength (positive = up, negative = down).

radius: f32

Vortex radius influence.

Bounce

Bounce particles with gravity-like motion.

Creates a bouncing ball effect.

Fields

height: f32

Bounce height.

frequency: f32

Bounce frequency (bounces per second).

damping: f32

Energy loss per bounce (0 = no loss, 1 = full loss).

Figure8

Figure-8 / Lissajous curve motion.

Creates infinity loops and complex orbital patterns.

Fields

width: f32

Horizontal amplitude.

height: f32

Vertical amplitude.

speed: f32

Animation speed.

ratio: f32

Frequency ratio (2 = figure-8, other values = Lissajous).

Helix

Helix/corkscrew motion along an axis.

Creates DNA-like spiraling motion.

Fields

axis: Vec3

Axis of helix progression.

radius: f32

Helix radius.

speed: f32

Rotation speed.

progression: f32

Forward movement speed along axis.

Flutter

Flutter - rapid small oscillations.

Creates leaf or butterfly-like trembling motion.

Fields

intensity: f32

Flutter intensity.

speed: f32

Flutter speed (higher = more rapid).

Brownian

Brownian motion - random walk.

Creates organic wandering motion that evolves over time.

Fields

intensity: f32

Movement intensity.

speed: f32

How fast the random direction changes.

Implementations

impl VertexEffect

pub fn to_wgsl(&self) -> String

Generate WGSL code that modifies transformation variables.

Available variables to read/modify:

• pos_offset: vec3<f32> - position offset (starts at 0)
• rotated_quad: vec2<f32> - quad coordinates (starts at quad_pos)
• size_mult: f32 - size multiplier (starts at 1.0)
• color_mod: vec3<f32> - color modifier (starts at particle_color)

Also available (read-only):

• particle_pos, particle_size, scale
• uniforms.time, instance_index, vertex_index

Trait Implementations

impl Clone for VertexEffect

fn clone(&self) -> VertexEffect

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VertexEffect

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.