Struct avian3d::dynamics::solver::SolverPlugin

pub struct SolverPlugin { /* private fields */ }

Manages and solves contacts, joints, and other constraints.

Note that the ContactConstraints are currently generated by tbe NarrowPhasePlugin.

Implementation

The solver primarily uses TGS Soft, an impulse-based solver with substepping and soft constraints. Warm starting is used to improve convergence, along with a relaxation pass to reduce overshooting.

Speculative collision is used by default to prevent tunneling. Optional sweep-based Continuous Collision Detection (CCD) is handled by the CcdPlugin.

Joints and user constraints are currently solved using Extended Position-Based Dynamics (XPBD). In the future, they may transition to an impulse-based approach as well.

Steps

Below are the main steps of the SolverPlugin.

1. Generate and prepare constraints
2. Substepping loop (runs the SubstepSchedule SubstepCount times)
   1. Integrate velocities
   2. Warm start
   3. Solve constraints with bias
   4. Integrate positions
   5. Solve constraints without bias to relax velocities
   6. Solve XPBD constraints (joints)
   7. Solve user-defined constraints
   8. Update velocities after XPBD constraint solving.
3. Apply restitution
4. Finalize positions by applying AccumulatedTranslation
5. Store contact impulses for next frame’s warm starting

Implementations

impl SolverPlugin

pub fn new_with_length_unit(unit: Scalar) -> Self

Creates a SolverPlugin with the given approximate dimensions of most objects.

The length unit will be used for initializing the PhysicsLengthUnit resource unless it already exists.

Trait Implementations

impl Default for SolverPlugin

fn default() -> Self

Returns the “default value” for a type.

impl Plugin for SolverPlugin

fn build(&self, app: &mut App)

Configures the App to which this plugin is added.

fn ready(&self, _app: &App) -> bool

Has the plugin finished its setup? This can be useful for plugins that need something asynchronous to happen before they can finish their setup, like the initialization of a renderer. Once the plugin is ready, finish should be called.

fn finish(&self, _app: &mut App)

Finish adding this plugin to the App, once all plugins registered are ready. This can be useful for plugins that depends on another plugin asynchronous setup, like the renderer.

fn cleanup(&self, _app: &mut App)

Runs after all plugins are built and finished, but before the app schedule is executed. This can be useful if you have some resource that other plugins need during their build step, but after build you want to remove it and send it to another thread.

fn name(&self) -> &str

Configures a name for the Plugin which is primarily used for checking plugin uniqueness and debugging.

fn is_unique(&self) -> bool

If the plugin can be meaningfully instantiated several times in an App, override this method to return false.