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feat: rename cfm_factor, damping_ratio to contact_cfm_factor and contact_damping_ratio

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This commit is contained in:
Sébastien Crozet
2024-05-25 11:30:41 +02:00
committed by Sébastien Crozet
parent 4737a96169
commit cdec395d09
6 changed files with 35 additions and 29 deletions
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40
src/dynamics/integration_parameters.rs
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@@ -25,25 +25,31 @@ pub struct IntegrationParameters {
pub min_ccd_dt: Real,
/// > 0: the damping ratio used by the springs for contact constraint stabilization.
/// Lower values make the constraints more compliant (more "springy", allowing more visible
///
/// Larger values make the constraints more compliant (allowing more visible
/// penetrations before stabilization).
/// (default `5.0`).
pub contact_damping_ratio: Real,
/// > 0: the natural frequency used by the springs for contact constraint regularization.
///
/// Increasing this value will make it so that penetrations get fixed more quickly at the
/// expense of potential jitter effects due to overshooting. In order to make the simulation
/// look stiffer, it is recommended to increase the [`Self::damping_ratio`] instead of this
/// look stiffer, it is recommended to increase the [`Self::contact_damping_ratio`] instead of this
/// value.
/// (default: `30.0`).
pub contact_natural_frequency: Real,
/// > 0: the natural frequency used by the springs for joint constraint regularization.
///
/// Increasing this value will make it so that penetrations get fixed more quickly.
/// (default: `1.0e6`).
pub joint_natural_frequency: Real,
/// The fraction of critical damping applied to the joint for constraints regularization.
///
/// Larger values make the constraints more compliant (allowing more joint
/// drift before stabilization).
/// (default `1.0`).
pub joint_damping_ratio: Real,
@@ -65,7 +71,7 @@ pub struct IntegrationParameters {
///
/// This value can be understood as the number of units-per-meter in your physical world compared
/// to a human-sized world in meter. For example, in a 2d game, if your typical object size is 100
/// pixels, set the `[`Self::length_unit`]` parameter to 100.0. The physics engine will interpret
/// pixels, set the [`Self::length_unit`] parameter to 100.0. The physics engine will interpret
/// it as if 100 pixels is equivalent to 1 meter in its various internal threshold.
/// (default `1.0`).
pub length_unit: Real,
@@ -74,7 +80,7 @@ pub struct IntegrationParameters {
///
/// This value is implicitly scaled by [`IntegrationParameters::length_unit`].
pub normalized_allowed_linear_error: Real,
/// Maximum amount of penetration the solver will attempt to resolve in one timestep.
/// Maximum amount of penetration the solver will attempt to resolve in one timestep (default: `10.0`).
///
/// This value is implicitly scaled by [`IntegrationParameters::length_unit`].
pub normalized_max_corrective_velocity: Real,
@@ -84,7 +90,7 @@ pub struct IntegrationParameters {
pub normalized_prediction_distance: Real,
/// The number of solver iterations run by the constraints solver for calculating forces (default: `4`).
pub num_solver_iterations: NonZeroUsize,
/// Number of addition friction resolution iteration run during the last solver sub-step (default: `4`).
/// Number of addition friction resolution iteration run during the last solver sub-step (default: `0`).
pub num_additional_friction_iterations: usize,
/// Number of internal Project Gauss Seidel (PGS) iterations run at each solver iteration (default: `1`).
pub num_internal_pgs_iterations: usize,
@@ -130,23 +136,23 @@ impl IntegrationParameters {
}
/// The contact’s spring angular frequency for constraints regularization.
pub fn angular_frequency(&self) -> Real {
pub fn contact_angular_frequency(&self) -> Real {
self.contact_natural_frequency * Real::two_pi()
}
/// The [`Self::erp`] coefficient, multiplied by the inverse timestep length.
pub fn erp_inv_dt(&self) -> Real {
let ang_freq = self.angular_frequency();
/// The [`Self::contact_erp`] coefficient, multiplied by the inverse timestep length.
pub fn contact_erp_inv_dt(&self) -> Real {
let ang_freq = self.contact_angular_frequency();
ang_freq / (self.dt * ang_freq + 2.0 * self.contact_damping_ratio)
}
/// The effective Error Reduction Parameter applied for calculating regularization forces
/// on contacts.
///
/// This parameter is computed automatically from [`Self::natural_frequency`],
/// [`Self::damping_ratio`] and the substep length.
pub fn erp(&self) -> Real {
self.dt * self.erp_inv_dt()
/// This parameter is computed automatically from [`Self::contact_natural_frequency`],
/// [`Self::contact_damping_ratio`] and the substep length.
pub fn contact_erp(&self) -> Real {
self.dt * self.contact_erp_inv_dt()
}
/// The joint’s spring angular frequency for constraint regularization.
@@ -171,11 +177,11 @@ impl IntegrationParameters {
/// The CFM factor to be used in the constraint resolution.
///
/// This parameter is computed automatically from [`Self::natural_frequency`],
/// [`Self::damping_ratio`] and the substep length.
pub fn cfm_factor(&self) -> Real {
/// This parameter is computed automatically from [`Self::contact_natural_frequency`],
/// [`Self::contact_damping_ratio`] and the substep length.
pub fn contact_cfm_factor(&self) -> Real {
// Compute CFM assuming a critically damped spring multiplied by the damping ratio.
let inv_erp_minus_one = 1.0 / self.erp() - 1.0;
let inv_erp_minus_one = 1.0 / self.contact_erp() - 1.0;
// let stiffness = 4.0 * damping_ratio * damping_ratio * projected_mass
// / (dt * dt * inv_erp_minus_one * inv_erp_minus_one);

4
src/dynamics/solver/contact_constraint/one_body_constraint.rs
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@@ -272,9 +272,9 @@ impl OneBodyConstraintBuilder {
rb2_pos: &Isometry<Real>,
constraint: &mut OneBodyConstraint,
) {
let cfm_factor = params.cfm_factor();
let cfm_factor = params.contact_cfm_factor();
let inv_dt = params.inv_dt();
let erp_inv_dt = params.erp_inv_dt();
let erp_inv_dt = params.contact_erp_inv_dt();
let all_infos = &self.infos[..constraint.num_contacts as usize];
let all_elements = &mut constraint.elements[..constraint.num_contacts as usize];

4
src/dynamics/solver/contact_constraint/one_body_constraint_simd.rs
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@@ -261,10 +261,10 @@ impl SimdOneBodyConstraintBuilder {
_multibodies: &MultibodyJointSet,
constraint: &mut OneBodyConstraintSimd,
) {
let cfm_factor = SimdReal::splat(params.cfm_factor());
let cfm_factor = SimdReal::splat(params.contact_cfm_factor());
let inv_dt = SimdReal::splat(params.inv_dt());
let allowed_lin_err = SimdReal::splat(params.allowed_linear_error());
let erp_inv_dt = SimdReal::splat(params.erp_inv_dt());
let erp_inv_dt = SimdReal::splat(params.contact_erp_inv_dt());
let max_corrective_velocity = SimdReal::splat(params.max_corrective_velocity());
let warmstart_coeff = SimdReal::splat(params.warmstart_coefficient);

4
src/dynamics/solver/contact_constraint/two_body_constraint.rs
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@@ -373,9 +373,9 @@ impl TwoBodyConstraintBuilder {
rb2_pos: &Isometry<Real>,
constraint: &mut TwoBodyConstraint,
) {
let cfm_factor = params.cfm_factor();
let cfm_factor = params.contact_cfm_factor();
let inv_dt = params.inv_dt();
let erp_inv_dt = params.erp_inv_dt();
let erp_inv_dt = params.contact_erp_inv_dt();
let all_infos = &self.infos[..constraint.num_contacts as usize];
let all_elements = &mut constraint.elements[..constraint.num_contacts as usize];

4
src/dynamics/solver/contact_constraint/two_body_constraint_simd.rs
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@@ -250,10 +250,10 @@ impl TwoBodyConstraintBuilderSimd {
_multibodies: &MultibodyJointSet,
constraint: &mut TwoBodyConstraintSimd,
) {
let cfm_factor = SimdReal::splat(params.cfm_factor());
let cfm_factor = SimdReal::splat(params.contact_cfm_factor());
let inv_dt = SimdReal::splat(params.inv_dt());
let allowed_lin_err = SimdReal::splat(params.allowed_linear_error());
let erp_inv_dt = SimdReal::splat(params.erp_inv_dt());
let erp_inv_dt = SimdReal::splat(params.contact_erp_inv_dt());
let max_corrective_velocity = SimdReal::splat(params.max_corrective_velocity());
let warmstart_coeff = SimdReal::splat(params.warmstart_coefficient);