Struct SpringChain 

pub struct SpringChain {
    pub positions: Vec<Vec3>,
    pub velocities: Vec<Vec3>,
    pub rest_lengths: Vec<f32>,
    pub stiffness: f32,
    pub damping: f32,
    pub masses: Vec<f32>,
    pub pin_head: bool,
    pub gravity: Vec3,
    pub iterations: usize,
}

A chain of N particles connected by spring-based distance constraints.

Useful for tails, tendrils, cloth edges, banner text, and rope physics. The first particle is optionally pinned to an anchor.

Fields

positions: Vec<Vec3>

Particle positions.

velocities: Vec<Vec3>

Particle velocities.

rest_lengths: Vec<f32>

Per-segment rest lengths (length = positions.len() - 1).

stiffness: f32

Constraint stiffness (0 = free-fall, 1 = rigid).

damping: f32

Velocity damping per step.

masses: Vec<f32>

Per-particle mass (1.0 default, first particle can be infinity).

pin_head: bool

If true, first particle is pinned to its initial position.

gravity: Vec3

Gravity applied per step.

iterations: usize

Number of constraint iterations per tick (higher = stiffer).

Implementations

impl SpringChain

pub fn new(anchor: Vec3, count: usize, segment_length: f32) -> Self

Create a chain hanging vertically from anchor.

count — number of particles (including anchor). segment_length — rest length per segment.

pub fn horizontal(anchor: Vec3, count: usize, segment_length: f32) -> Self

Create a chain for a banner or horizontal tendril.

pub fn set_anchor(&mut self, pos: Vec3)

Set the anchor (first particle) position.

pub fn tick(&mut self, dt: f32)

Simulate one physics step.

Applies gravity, integrates velocities, then resolves constraints.

pub fn apply_impulse(&mut self, index: usize, impulse: Vec3)

Apply an impulse to a specific particle.

pub fn apply_wind(&mut self, wind: Vec3, dt: f32)

Apply a wind force to all non-infinite-mass particles.

pub fn tip(&self) -> Vec3

Get tip (last particle) position.

pub fn total_length(&self) -> f32

Total chain length.

pub fn extension_ratio(&self) -> f32

Current extension ratio (actual_length / rest_length).

Trait Implementations

impl Clone for SpringChain

fn clone(&self) -> SpringChain

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SpringChain

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

Formats the value using the given formatter.