Struct jumpy::core::physics::rapier::IntegrationParameters

pub struct IntegrationParameters {

    pub dt: f32,
    pub min_ccd_dt: f32,
    pub erp: f32,
    pub damping_ratio: f32,
    pub joint_erp: f32,
    pub joint_damping_ratio: f32,
    pub allowed_linear_error: f32,
    pub max_penetration_correction: f32,
    pub prediction_distance: f32,
    pub num_solver_iterations: NonZero<usize>,
    pub num_additional_friction_iterations: usize,
    pub num_internal_pgs_iterations: usize,
    pub min_island_size: usize,
    pub max_ccd_substeps: usize,
}

Parameters for a time-step of the physics engine.

Fields

dt: f32

The timestep length (default: 1.0 / 60.0)

min_ccd_dt: f32

Minimum timestep size when using CCD with multiple substeps (default 1.0 / 60.0 / 100.0)

When CCD with multiple substeps is enabled, the timestep is subdivided into smaller pieces. This timestep subdivision won’t generate timestep lengths smaller than min_ccd_dt.

Setting this to a large value will reduce the opportunity to performing CCD substepping, resulting in potentially more time dropped by the motion-clamping mechanism. Setting this to an very small value may lead to numerical instabilities.

erp: f32

0-1: multiplier for how much of the constraint violation (e.g. contact penetration) will be compensated for during the velocity solve. (default 0.8).

damping_ratio: f32

0-1: the damping ratio used by the springs for Baumgarte constraints stabilization. Lower values make the constraints more compliant (more “springy”, allowing more visible penetrations before stabilization). (default 0.25).

joint_erp: f32

0-1: multiplier for how much of the joint violation will be compensated for during the velocity solve. (default 1.0).

joint_damping_ratio: f32

The fraction of critical damping applied to the joint for constraints regularization. (default 0.25).

allowed_linear_error: f32

Amount of penetration the engine wont attempt to correct (default: 0.001m).

max_penetration_correction: f32

Maximum amount of penetration the solver will attempt to resolve in one timestep.

prediction_distance: f32

The maximal distance separating two objects that will generate predictive contacts (default: 0.002).

num_solver_iterations: NonZero<usize>

The number of solver iterations run by the constraints solver for calculating forces (default: 4).

num_additional_friction_iterations: usize

Number of addition friction resolution iteration run during the last solver sub-step (default: 4).

num_internal_pgs_iterations: usize

Number of internal Project Gauss Seidel (PGS) iterations run at each solver iteration (default: 1).

min_island_size: usize

Minimum number of dynamic bodies in each active island (default: 128).

max_ccd_substeps: usize

Maximum number of substeps performed by the solver (default: 1).

Implementations

impl IntegrationParameters

pub fn switch_to_standard_pgs_solver(&mut self)

Configures the integration parameters to match the old PGS solver from Rapier version <= 0.17.

This solver was slightly faster than the new one but resulted in less stable joints and worse convergence rates.

This should only be used for comparison purpose or if you are experiencing problems with the new solver.

NOTE: this does not affect any [RigidBody::additional_solver_iterations] that will still create solver iterations based on the new “small-steps” PGS solver. NOTE: this resets Self::erp, Self::damping_ratio, Self::joint_erp, Self::joint_damping_ratio to their former default values.

pub fn switch_to_small_steps_pgs_solver(&mut self)

Configures the integration parameters to match the new “small-steps” PGS solver from Rapier version >= 0.18.

The “small-steps” PGS solver is the default one given by Self::default() so calling this function is generally not needed unless Self::switch_to_standard_pgs_solver() was called.

This solver results in more stable joints and significantly better convergence rates but is slightly slower in its default settings.

NOTE: this resets Self::erp, Self::damping_ratio, Self::joint_erp, Self::joint_damping_ratio to their default values.

pub fn inv_dt(&self) -> f32

The inverse of the time-stepping length, i.e. the steps per seconds (Hz).

This is zero if self.dt is zero.

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

👎Deprecated: You can just set the IntegrationParams::dt value directly

Sets the time-stepping length.

pub fn set_inv_dt(&mut self, inv_dt: f32)

Sets the inverse time-stepping length (i.e. the frequency).

This automatically recompute self.dt.

pub fn erp_inv_dt(&self) -> f32

The ERP coefficient, multiplied by the inverse timestep length.

pub fn joint_erp_inv_dt(&self) -> f32

The joint ERP coefficient, multiplied by the inverse timestep length.

pub fn cfm_factor(&self) -> f32

The CFM factor to be used in the constraints resolution.

pub fn joint_cfm_coeff(&self) -> f32

The CFM (constraints force mixing) coefficient applied to all joints for constraints regularization

Trait Implementations

impl Clone for IntegrationParameters

fn clone(&self) -> IntegrationParameters

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for IntegrationParameters

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

Formats the value using the given formatter.

impl Default for IntegrationParameters

fn default() -> IntegrationParameters

Returns the “default value” for a type.

impl Copy for IntegrationParameters