Files
rapier/src/dynamics/rigid_body.rs
2021-04-01 09:46:13 +02:00

1120 lines
41 KiB
Rust

use crate::dynamics::MassProperties;
use crate::geometry::{
Collider, ColliderHandle, ColliderSet, InteractionGraph, RigidBodyGraphIndex,
};
use crate::math::{
AngVector, AngularInertia, Isometry, Point, Real, Rotation, Translation, Vector,
};
use crate::utils::{self, WAngularInertia, WCross, WDot};
use na::ComplexField;
use num::Zero;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// The status of a body, governing the way it is affected by external forces.
pub enum BodyStatus {
/// A `BodyStatus::Dynamic` body can be affected by all external forces.
Dynamic,
/// A `BodyStatus::Static` body cannot be affected by external forces.
Static,
/// A `BodyStatus::Kinematic` body cannot be affected by any external forces but can be controlled
/// by the user at the position level while keeping realistic one-way interaction with dynamic bodies.
///
/// One-way interaction means that a kinematic body can push a dynamic body, but a kinematic body
/// cannot be pushed by anything. In other words, the trajectory of a kinematic body can only be
/// modified by the user and is independent from any contact or joint it is involved in.
Kinematic,
// Semikinematic, // A kinematic that performs automatic CCD with the static environment to avoid traversing it?
// Disabled,
}
bitflags::bitflags! {
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// Flags affecting the behavior of the constraints solver for a given contact manifold.
pub(crate) struct RigidBodyFlags: u8 {
const TRANSLATION_LOCKED = 1 << 0;
const ROTATION_LOCKED_X = 1 << 1;
const ROTATION_LOCKED_Y = 1 << 2;
const ROTATION_LOCKED_Z = 1 << 3;
const CCD_ENABLED = 1 << 4;
const CCD_ACTIVE = 1 << 5;
}
}
bitflags::bitflags! {
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// Flags describing how the rigid-body has been modified by the user.
pub(crate) struct RigidBodyChanges: u32 {
const MODIFIED = 1 << 0;
const POSITION = 1 << 1;
const SLEEP = 1 << 2;
const COLLIDERS = 1 << 3;
const BODY_STATUS = 1 << 4;
}
}
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// A rigid body.
///
/// To create a new rigid-body, use the `RigidBodyBuilder` structure.
#[derive(Debug, Clone)]
pub struct RigidBody {
/// The world-space position of the rigid-body.
pub(crate) position: Isometry<Real>,
/// The next position of the rigid-body.
///
/// At the beginning of the timestep, and when the
/// timestep is complete we must have position == next_position
/// except for kinematic bodies.
///
/// The next_position is updated after the velocity and position
/// resolution. Then it is either validated (ie. we set position := set_position)
/// or clamped by CCD.
pub(crate) next_position: Isometry<Real>,
/// The local mass properties of the rigid-body.
pub(crate) mass_properties: MassProperties,
/// The world-space center of mass of the rigid-body.
pub world_com: Point<Real>,
/// The inverse mass taking into account translation locking.
pub effective_inv_mass: Real,
/// The square-root of the world-space inverse angular inertia tensor of the rigid-body,
/// taking into account rotation locking.
pub effective_world_inv_inertia_sqrt: AngularInertia<Real>,
/// The linear velocity of the rigid-body.
pub(crate) linvel: Vector<Real>,
/// The angular velocity of the rigid-body.
pub(crate) angvel: AngVector<Real>,
/// Damping factor for gradually slowing down the translational motion of the rigid-body.
pub linear_damping: Real,
/// Damping factor for gradually slowing down the angular motion of the rigid-body.
pub angular_damping: Real,
/// Accumulation of external forces (only for dynamic bodies).
pub(crate) force: Vector<Real>,
/// Accumulation of external torques (only for dynamic bodies).
pub(crate) torque: AngVector<Real>,
pub(crate) colliders: Vec<ColliderHandle>,
pub(crate) gravity_scale: Real,
/// Whether or not this rigid-body is sleeping.
pub activation: ActivationStatus,
pub(crate) joint_graph_index: RigidBodyGraphIndex,
pub(crate) active_island_id: usize,
pub(crate) active_set_id: usize,
pub(crate) active_set_offset: usize,
pub(crate) active_set_timestamp: u32,
flags: RigidBodyFlags,
pub(crate) changes: RigidBodyChanges,
/// The status of the body, governing how it is affected by external forces.
body_status: BodyStatus,
/// The dominance group this rigid-body is part of.
dominance_group: i8,
/// User-defined data associated to this rigid-body.
pub user_data: u128,
pub(crate) ccd_thickness: Real,
pub(crate) ccd_max_dist: Real,
}
impl RigidBody {
fn new() -> Self {
Self {
position: Isometry::identity(),
next_position: Isometry::identity(),
mass_properties: MassProperties::zero(),
world_com: Point::origin(),
effective_inv_mass: 0.0,
effective_world_inv_inertia_sqrt: AngularInertia::zero(),
linvel: Vector::zeros(),
angvel: na::zero(),
force: Vector::zeros(),
torque: na::zero(),
gravity_scale: 1.0,
linear_damping: 0.0,
angular_damping: 0.0,
colliders: Vec::new(),
activation: ActivationStatus::new_active(),
joint_graph_index: InteractionGraph::<(), ()>::invalid_graph_index(),
active_island_id: 0,
active_set_id: 0,
active_set_offset: 0,
active_set_timestamp: 0,
flags: RigidBodyFlags::empty(),
changes: RigidBodyChanges::all(),
body_status: BodyStatus::Dynamic,
dominance_group: 0,
user_data: 0,
ccd_thickness: Real::MAX,
ccd_max_dist: 0.0,
}
}
pub(crate) fn reset_internal_references(&mut self) {
self.colliders = Vec::new();
self.joint_graph_index = InteractionGraph::<(), ()>::invalid_graph_index();
self.active_island_id = 0;
self.active_set_id = 0;
self.active_set_offset = 0;
self.active_set_timestamp = 0;
}
pub(crate) fn add_gravity(&mut self, gravity: Vector<Real>) {
if self.effective_inv_mass != 0.0 {
self.force += gravity * self.gravity_scale * self.mass();
}
}
#[cfg(not(feature = "parallel"))] // in parallel solver this is not needed
pub(crate) fn integrate_accelerations(&mut self, dt: Real) {
let linear_acc = self.force * self.effective_inv_mass;
let angular_acc = self.effective_world_inv_inertia_sqrt
* (self.effective_world_inv_inertia_sqrt * self.torque);
self.linvel += linear_acc * dt;
self.angvel += angular_acc * dt;
}
/// The status of this rigid-body.
pub fn body_status(&self) -> BodyStatus {
self.body_status
}
/// Sets the status of this rigid-body.
pub fn set_body_status(&mut self, status: BodyStatus) {
if status != self.body_status {
self.changes.insert(RigidBodyChanges::BODY_STATUS);
self.body_status = status;
}
}
/// The mass properties of this rigid-body.
#[inline]
pub fn mass_properties(&self) -> &MassProperties {
&self.mass_properties
}
/// The dominance group of this rigid-body.
///
/// This method always returns `i8::MAX + 1` for non-dynamic
/// rigid-bodies.
#[inline]
pub fn effective_dominance_group(&self) -> i16 {
if self.is_dynamic() {
self.dominance_group as i16
} else {
i8::MAX as i16 + 1
}
}
/// Enables of disable CCD (continuous collision-detection) for this rigid-body.
pub fn enable_ccd(&mut self, enabled: bool) {
self.flags.set(RigidBodyFlags::CCD_ENABLED, enabled)
}
/// Is CCD (continous collision-detection) enabled for this rigid-body?
pub fn is_ccd_enabled(&self) -> bool {
self.flags.contains(RigidBodyFlags::CCD_ENABLED)
}
// This is different from `is_ccd_enabled`. This checks that CCD
// is active for this rigid-body, i.e., if it was seen to move fast
// enough to justify a CCD run.
/// Is CCD active for this rigid-body?
///
/// The CCD is considered active if the rigid-body is moving at
/// a velocity greater than an automatically-computed threshold.
///
/// This is not the same as `self.is_ccd_enabled` which only
/// checks if CCD is allowed to run for this rigid-body or if
/// it is completely disabled (independently from its velocity).
pub fn is_ccd_active(&self) -> bool {
self.flags.contains(RigidBodyFlags::CCD_ACTIVE)
}
pub(crate) fn update_ccd_active_flag(&mut self, dt: Real, include_forces: bool) {
let ccd_active = self.is_ccd_enabled() && self.is_moving_fast(dt, include_forces);
self.flags.set(RigidBodyFlags::CCD_ACTIVE, ccd_active);
}
pub(crate) fn is_moving_fast(&self, dt: Real, include_forces: bool) -> bool {
if self.is_dynamic() {
// NOTE: for the threshold we don't use the exact CCD thickness. Theoretically, we
// should use `self.ccd_thickness - smallest_contact_dist` where `smallest_contact_dist`
// is the deepest contact (the contact with the largest penetration depth, i.e., the
// negative `dist` with the largest absolute value.
// However, getting this penetration depth assumes querying the contact graph from
// the narrow-phase, which can be pretty expensive. So we use the CCD thickness
// divided by 10 right now. We will see in practice if this value is OK or if we
// should use a smaller (to be less conservative) or larger divisor (to be more conservative).
let threshold = self.ccd_thickness / 10.0;
if include_forces {
let linear_part = (self.linvel + self.force * dt).norm();
#[cfg(feature = "dim2")]
let angular_part = (self.angvel + self.torque * dt).abs() * self.ccd_max_dist;
#[cfg(feature = "dim3")]
let angular_part = (self.angvel + self.torque * dt).norm() * self.ccd_max_dist;
let vel_with_forces = linear_part + angular_part;
vel_with_forces > threshold
} else {
self.max_point_velocity() * dt > threshold
}
} else {
false
}
}
pub(crate) fn max_point_velocity(&self) -> Real {
#[cfg(feature = "dim2")]
return self.linvel.norm() + self.angvel.abs() * self.ccd_max_dist;
#[cfg(feature = "dim3")]
return self.linvel.norm() + self.angvel.norm() * self.ccd_max_dist;
}
/// Sets the rigid-body's initial mass properties.
///
/// If `wake_up` is `true` then the rigid-body will be woken up if it was
/// put to sleep because it did not move for a while.
#[inline]
pub fn set_mass_properties(&mut self, props: MassProperties, wake_up: bool) {
if self.is_dynamic() && wake_up {
self.wake_up(true);
}
self.mass_properties = props;
self.update_world_mass_properties();
}
/// The handles of colliders attached to this rigid body.
pub fn colliders(&self) -> &[ColliderHandle] {
&self.colliders[..]
}
/// Is this rigid body dynamic?
///
/// A dynamic body can move freely and is affected by forces.
pub fn is_dynamic(&self) -> bool {
self.body_status == BodyStatus::Dynamic
}
/// Is this rigid body kinematic?
///
/// A kinematic body can move freely but is not affected by forces.
pub fn is_kinematic(&self) -> bool {
self.body_status == BodyStatus::Kinematic
}
/// Is this rigid body static?
///
/// A static body cannot move and is not affected by forces.
pub fn is_static(&self) -> bool {
self.body_status == BodyStatus::Static
}
/// The mass of this rigid body.
///
/// Returns zero if this rigid body has an infinite mass.
pub fn mass(&self) -> Real {
utils::inv(self.mass_properties.inv_mass)
}
/// The predicted position of this rigid-body.
///
/// If this rigid-body is kinematic this value is set by the `set_next_kinematic_position`
/// method and is used for estimating the kinematic body velocity at the next timestep.
/// For non-kinematic bodies, this value is currently unspecified.
pub fn next_position(&self) -> &Isometry<Real> {
&self.next_position
}
/// The scale factor applied to the gravity affecting this rigid-body.
pub fn gravity_scale(&self) -> Real {
self.gravity_scale
}
/// Sets the gravity scale facter for this rigid-body.
pub fn set_gravity_scale(&mut self, scale: Real, wake_up: bool) {
if wake_up && self.activation.sleeping {
self.changes.insert(RigidBodyChanges::SLEEP);
self.activation.sleeping = false;
}
self.gravity_scale = scale;
}
/// Adds a collider to this rigid-body.
pub(crate) fn add_collider(&mut self, handle: ColliderHandle, coll: &Collider) {
self.changes.set(
RigidBodyChanges::MODIFIED | RigidBodyChanges::COLLIDERS,
true,
);
self.ccd_thickness = self.ccd_thickness.min(coll.shape().ccd_thickness());
let shape_bsphere = coll
.shape()
.compute_bounding_sphere(coll.position_wrt_parent());
self.ccd_max_dist = self
.ccd_max_dist
.max(shape_bsphere.center.coords.norm() + shape_bsphere.radius);
let mass_properties = coll
.mass_properties()
.transform_by(coll.position_wrt_parent());
self.colliders.push(handle);
self.mass_properties += mass_properties;
self.update_world_mass_properties();
}
pub(crate) fn update_colliders_positions(&mut self, colliders: &mut ColliderSet) {
for handle in &self.colliders {
// NOTE: we use `get_mut_internal_with_modification_tracking` here because we want to
// benefit from the modification tracking to know the colliders
// we need to update the broad-phase and narrow-phase for.
let collider = colliders
.get_mut_internal_with_modification_tracking(*handle)
.unwrap();
collider.set_position(self.position * collider.delta);
}
}
/// Removes a collider from this rigid-body.
pub(crate) fn remove_collider_internal(&mut self, handle: ColliderHandle, coll: &Collider) {
if let Some(i) = self.colliders.iter().position(|e| *e == handle) {
self.changes.set(RigidBodyChanges::COLLIDERS, true);
self.colliders.swap_remove(i);
let mass_properties = coll
.mass_properties()
.transform_by(coll.position_wrt_parent());
self.mass_properties -= mass_properties;
self.update_world_mass_properties();
}
}
/// Put this rigid body to sleep.
///
/// A sleeping body no longer moves and is no longer simulated by the physics engine unless
/// it is waken up. It can be woken manually with `self.wake_up` or automatically due to
/// external forces like contacts.
pub fn sleep(&mut self) {
self.activation.energy = 0.0;
self.activation.sleeping = true;
self.linvel = na::zero();
self.angvel = na::zero();
}
/// Wakes up this rigid body if it is sleeping.
///
/// If `strong` is `true` then it is assured that the rigid-body will
/// remain awake during multiple subsequent timesteps.
pub fn wake_up(&mut self, strong: bool) {
if self.activation.sleeping {
self.changes.insert(RigidBodyChanges::SLEEP);
self.activation.sleeping = false;
}
if (strong || self.activation.energy == 0.0) && self.is_dynamic() {
self.activation.energy = self.activation.threshold.abs() * 2.0;
}
}
pub(crate) fn update_energy(&mut self) {
let mix_factor = 0.01;
let new_energy = (1.0 - mix_factor) * self.activation.energy
+ mix_factor * (self.linvel.norm_squared() + self.angvel.gdot(self.angvel));
self.activation.energy = new_energy.min(self.activation.threshold.abs() * 4.0);
}
/// Is this rigid body sleeping?
pub fn is_sleeping(&self) -> bool {
// TODO: should we:
// - return false for static bodies.
// - return true for non-sleeping dynamic bodies.
// - return true only for kinematic bodies with non-zero velocity?
self.activation.sleeping
}
/// Is the velocity of this body not zero?
pub fn is_moving(&self) -> bool {
!self.linvel.is_zero() || !self.angvel.is_zero()
}
/// Computes the predict position of this rigid-body after `dt` seconds, taking
/// into account its velocities and external forces applied to it.
pub fn predict_position_using_velocity_and_forces(&self, dt: Real) -> Isometry<Real> {
let dlinvel = self.force * (self.effective_inv_mass * dt);
let dangvel = self
.effective_world_inv_inertia_sqrt
.transform_vector(self.torque * dt);
let linvel = self.linvel + dlinvel;
let angvel = self.angvel + dangvel;
let com = self.position * self.mass_properties.local_com;
let shift = Translation::from(com.coords);
shift * Isometry::new(linvel * dt, angvel * dt) * shift.inverse() * self.position
}
pub(crate) fn integrate_velocity(&self, dt: Real) -> Isometry<Real> {
let com = self.position * self.mass_properties.local_com;
let shift = Translation::from(com.coords);
shift * Isometry::new(self.linvel * dt, self.angvel * dt) * shift.inverse()
}
pub(crate) fn integrate_next_position(&mut self, dt: Real, apply_damping: bool) {
// TODO: do we want to apply damping before or after the velocity integration?
if apply_damping {
self.linvel *= 1.0 / (1.0 + dt * self.linear_damping);
self.angvel *= 1.0 / (1.0 + dt * self.angular_damping);
}
self.next_position = self.integrate_velocity(dt) * self.position;
let _ = self.next_position.rotation.renormalize();
}
/// The linear velocity of this rigid-body.
pub fn linvel(&self) -> &Vector<Real> {
&self.linvel
}
/// The angular velocity of this rigid-body.
#[cfg(feature = "dim2")]
pub fn angvel(&self) -> Real {
self.angvel
}
/// The angular velocity of this rigid-body.
#[cfg(feature = "dim3")]
pub fn angvel(&self) -> &Vector<Real> {
&self.angvel
}
/// The linear velocity of this rigid-body.
///
/// If `wake_up` is `true` then the rigid-body will be woken up if it was
/// put to sleep because it did not move for a while.
pub fn set_linvel(&mut self, linvel: Vector<Real>, wake_up: bool) {
self.linvel = linvel;
if self.is_dynamic() && wake_up {
self.wake_up(true)
}
}
/// The angular velocity of this rigid-body.
///
/// If `wake_up` is `true` then the rigid-body will be woken up if it was
/// put to sleep because it did not move for a while.
#[cfg(feature = "dim2")]
pub fn set_angvel(&mut self, angvel: Real, wake_up: bool) {
self.angvel = angvel;
if self.is_dynamic() && wake_up {
self.wake_up(true)
}
}
/// The angular velocity of this rigid-body.
///
/// If `wake_up` is `true` then the rigid-body will be woken up if it was
/// put to sleep because it did not move for a while.
#[cfg(feature = "dim3")]
pub fn set_angvel(&mut self, angvel: Vector<Real>, wake_up: bool) {
self.angvel = angvel;
if self.is_dynamic() && wake_up {
self.wake_up(true)
}
}
/// The world-space position of this rigid-body.
pub fn position(&self) -> &Isometry<Real> {
&self.position
}
/// Sets the position and `next_kinematic_position` of this rigid body.
///
/// This will teleport the rigid-body to the specified position/orientation,
/// completely ignoring any physics rule. If this body is kinematic, this will
/// also set the next kinematic position to the same value, effectively
/// resetting to zero the next interpolated velocity of the kinematic body.
///
/// If `wake_up` is `true` then the rigid-body will be woken up if it was
/// put to sleep because it did not move for a while.
pub fn set_position(&mut self, pos: Isometry<Real>, wake_up: bool) {
self.changes.insert(RigidBodyChanges::POSITION);
self.position = pos;
self.next_position = pos;
// TODO: Do we really need to check that the body isn't dynamic?
if wake_up && self.is_dynamic() {
self.wake_up(true)
}
}
pub(crate) fn set_next_position(&mut self, pos: Isometry<Real>) {
self.next_position = pos;
}
/// If this rigid body is kinematic, sets its future position after the next timestep integration.
pub fn set_next_kinematic_position(&mut self, pos: Isometry<Real>) {
if self.is_kinematic() {
self.next_position = pos;
}
}
pub(crate) fn compute_velocity_from_next_position(&mut self, inv_dt: Real) {
let dpos = self.next_position * self.position.inverse();
#[cfg(feature = "dim2")]
{
self.angvel = dpos.rotation.angle() * inv_dt;
}
#[cfg(feature = "dim3")]
{
self.angvel = dpos.rotation.scaled_axis() * inv_dt;
}
self.linvel = dpos.translation.vector * inv_dt;
}
pub(crate) fn update_world_mass_properties(&mut self) {
self.world_com = self.mass_properties.world_com(&self.position);
self.effective_inv_mass = self.mass_properties.inv_mass;
self.effective_world_inv_inertia_sqrt = self
.mass_properties
.world_inv_inertia_sqrt(&self.position.rotation);
// Take into account translation/rotation locking.
if self.flags.contains(RigidBodyFlags::TRANSLATION_LOCKED) {
self.effective_inv_mass = 0.0;
}
#[cfg(feature = "dim2")]
{
if self.flags.contains(RigidBodyFlags::ROTATION_LOCKED_Z) {
self.effective_world_inv_inertia_sqrt = 0.0;
}
}
#[cfg(feature = "dim3")]
{
if self.flags.contains(RigidBodyFlags::ROTATION_LOCKED_X) {
self.effective_world_inv_inertia_sqrt.m11 = 0.0;
self.effective_world_inv_inertia_sqrt.m12 = 0.0;
self.effective_world_inv_inertia_sqrt.m13 = 0.0;
}
if self.flags.contains(RigidBodyFlags::ROTATION_LOCKED_Y) {
self.effective_world_inv_inertia_sqrt.m22 = 0.0;
self.effective_world_inv_inertia_sqrt.m12 = 0.0;
self.effective_world_inv_inertia_sqrt.m23 = 0.0;
}
if self.flags.contains(RigidBodyFlags::ROTATION_LOCKED_Z) {
self.effective_world_inv_inertia_sqrt.m33 = 0.0;
self.effective_world_inv_inertia_sqrt.m13 = 0.0;
self.effective_world_inv_inertia_sqrt.m23 = 0.0;
}
}
}
}
/// ## Applying forces and torques
impl RigidBody {
/// Applies a force at the center-of-mass of this rigid-body.
/// The force will be applied in the next simulation step.
/// This does nothing on non-dynamic bodies.
pub fn apply_force(&mut self, force: Vector<Real>, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.force += force;
if wake_up {
self.wake_up(true);
}
}
}
/// Applies a torque at the center-of-mass of this rigid-body.
/// The torque will be applied in the next simulation step.
/// This does nothing on non-dynamic bodies.
#[cfg(feature = "dim2")]
pub fn apply_torque(&mut self, torque: Real, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.torque += torque;
if wake_up {
self.wake_up(true);
}
}
}
/// Applies a torque at the center-of-mass of this rigid-body.
/// The torque will be applied in the next simulation step.
/// This does nothing on non-dynamic bodies.
#[cfg(feature = "dim3")]
pub fn apply_torque(&mut self, torque: Vector<Real>, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.torque += torque;
if wake_up {
self.wake_up(true);
}
}
}
/// Applies a force at the given world-space point of this rigid-body.
/// The force will be applied in the next simulation step.
/// This does nothing on non-dynamic bodies.
pub fn apply_force_at_point(&mut self, force: Vector<Real>, point: Point<Real>, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.force += force;
self.torque += (point - self.world_com).gcross(force);
if wake_up {
self.wake_up(true);
}
}
}
}
/// ## Applying impulses and angular impulses
impl RigidBody {
/// Applies an impulse at the center-of-mass of this rigid-body.
/// The impulse is applied right away, changing the linear velocity.
/// This does nothing on non-dynamic bodies.
pub fn apply_impulse(&mut self, impulse: Vector<Real>, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.linvel += impulse * self.effective_inv_mass;
if wake_up {
self.wake_up(true);
}
}
}
/// Applies an angular impulse at the center-of-mass of this rigid-body.
/// The impulse is applied right away, changing the angular velocity.
/// This does nothing on non-dynamic bodies.
#[cfg(feature = "dim2")]
pub fn apply_torque_impulse(&mut self, torque_impulse: Real, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.angvel += self.effective_world_inv_inertia_sqrt
* (self.effective_world_inv_inertia_sqrt * torque_impulse);
if wake_up {
self.wake_up(true);
}
}
}
/// Applies an angular impulse at the center-of-mass of this rigid-body.
/// The impulse is applied right away, changing the angular velocity.
/// This does nothing on non-dynamic bodies.
#[cfg(feature = "dim3")]
pub fn apply_torque_impulse(&mut self, torque_impulse: Vector<Real>, wake_up: bool) {
if self.body_status == BodyStatus::Dynamic {
self.angvel += self.effective_world_inv_inertia_sqrt
* (self.effective_world_inv_inertia_sqrt * torque_impulse);
if wake_up {
self.wake_up(true);
}
}
}
/// Applies an impulse at the given world-space point of this rigid-body.
/// The impulse is applied right away, changing the linear and/or angular velocities.
/// This does nothing on non-dynamic bodies.
pub fn apply_impulse_at_point(
&mut self,
impulse: Vector<Real>,
point: Point<Real>,
wake_up: bool,
) {
let torque_impulse = (point - self.world_com).gcross(impulse);
self.apply_impulse(impulse, wake_up);
self.apply_torque_impulse(torque_impulse, wake_up);
}
}
impl RigidBody {
/// The velocity of the given world-space point on this rigid-body.
pub fn velocity_at_point(&self, point: &Point<Real>) -> Vector<Real> {
let dpt = point - self.world_com;
self.linvel + self.angvel.gcross(dpt)
}
/// The kinetic energy of this body.
pub fn kinetic_energy(&self) -> Real {
let mut energy = (self.mass() * self.linvel().norm_squared()) / 2.0;
#[cfg(feature = "dim2")]
if !self.effective_world_inv_inertia_sqrt.is_zero() {
let inertia_sqrt = 1.0 / self.effective_world_inv_inertia_sqrt;
energy += (inertia_sqrt * self.angvel).powi(2) / 2.0;
}
#[cfg(feature = "dim3")]
if !self.effective_world_inv_inertia_sqrt.is_zero() {
let inertia_sqrt = self.effective_world_inv_inertia_sqrt.inverse_unchecked();
energy += (inertia_sqrt * self.angvel).norm_squared() / 2.0;
}
energy
}
/// The potential energy of this body in a gravity field.
pub fn gravitational_potential_energy(&self, dt: Real, gravity: Vector<Real>) -> Real {
let world_com = self.mass_properties().world_com(&self.position).coords;
// Project position back along velocity vector one half-step (leap-frog)
// to sync up the potential energy with the kinetic energy:
let world_com = world_com - self.linvel() * (dt / 2.0);
-self.mass() * self.gravity_scale() * gravity.dot(&world_com)
}
}
/// A builder for rigid-bodies.
pub struct RigidBodyBuilder {
position: Isometry<Real>,
linvel: Vector<Real>,
angvel: AngVector<Real>,
gravity_scale: Real,
linear_damping: Real,
angular_damping: Real,
body_status: BodyStatus,
flags: RigidBodyFlags,
mass_properties: MassProperties,
can_sleep: bool,
sleeping: bool,
ccd_enabled: bool,
dominance_group: i8,
user_data: u128,
}
impl RigidBodyBuilder {
/// Initialize a new builder for a rigid body which is either static, dynamic, or kinematic.
pub fn new(body_status: BodyStatus) -> Self {
Self {
position: Isometry::identity(),
linvel: Vector::zeros(),
angvel: na::zero(),
gravity_scale: 1.0,
linear_damping: 0.0,
angular_damping: 0.0,
body_status,
flags: RigidBodyFlags::empty(),
mass_properties: MassProperties::zero(),
can_sleep: true,
sleeping: false,
ccd_enabled: false,
dominance_group: 0,
user_data: 0,
}
}
/// Initializes the builder of a new static rigid body.
pub fn new_static() -> Self {
Self::new(BodyStatus::Static)
}
/// Initializes the builder of a new kinematic rigid body.
pub fn new_kinematic() -> Self {
Self::new(BodyStatus::Kinematic)
}
/// Initializes the builder of a new dynamic rigid body.
pub fn new_dynamic() -> Self {
Self::new(BodyStatus::Dynamic)
}
/// Sets the scale applied to the gravity force affecting the rigid-body to be created.
pub fn gravity_scale(mut self, x: Real) -> Self {
self.gravity_scale = x;
self
}
/// Sets the dominance group of this rigid-body.
pub fn dominance_group(mut self, group: i8) -> Self {
self.dominance_group = group;
self
}
/// Sets the initial translation of the rigid-body to be created.
#[cfg(feature = "dim2")]
pub fn translation(mut self, x: Real, y: Real) -> Self {
self.position.translation.x = x;
self.position.translation.y = y;
self
}
/// Sets the initial translation of the rigid-body to be created.
#[cfg(feature = "dim3")]
pub fn translation(mut self, x: Real, y: Real, z: Real) -> Self {
self.position.translation.x = x;
self.position.translation.y = y;
self.position.translation.z = z;
self
}
/// Sets the initial orientation of the rigid-body to be created.
pub fn rotation(mut self, angle: AngVector<Real>) -> Self {
self.position.rotation = Rotation::new(angle);
self
}
/// Sets the initial position (translation and orientation) of the rigid-body to be created.
pub fn position(mut self, pos: Isometry<Real>) -> Self {
self.position = pos;
self
}
/// An arbitrary user-defined 128-bit integer associated to the rigid-bodies built by this builder.
pub fn user_data(mut self, data: u128) -> Self {
self.user_data = data;
self
}
/// Sets the additional mass properties of the rigid-body being built.
///
/// Note that "additional" means that the final mass properties of the rigid-bodies depends
/// on the initial mass-properties of the rigid-body (set by this method)
/// to which is added the contributions of all the colliders with non-zero density
/// attached to this rigid-body.
///
/// Therefore, if you want your provided mass properties to be the final
/// mass properties of your rigid-body, don't attach colliders to it, or
/// only attach colliders with densities equal to zero.
pub fn additional_mass_properties(mut self, props: MassProperties) -> Self {
self.mass_properties = props;
self
}
/// Prevents this rigid-body from translating because of forces.
pub fn lock_translations(mut self) -> Self {
self.flags.set(RigidBodyFlags::TRANSLATION_LOCKED, true);
self
}
/// Prevents this rigid-body from rotating because of forces.
pub fn lock_rotations(mut self) -> Self {
self.flags.set(RigidBodyFlags::ROTATION_LOCKED_X, true);
self.flags.set(RigidBodyFlags::ROTATION_LOCKED_Y, true);
self.flags.set(RigidBodyFlags::ROTATION_LOCKED_Z, true);
self
}
/// Only allow rotations of this rigid-body around specific coordinate axes.
#[cfg(feature = "dim3")]
pub fn restrict_rotations(
mut self,
allow_rotations_x: bool,
allow_rotations_y: bool,
allow_rotations_z: bool,
) -> Self {
self.flags
.set(RigidBodyFlags::ROTATION_LOCKED_X, !allow_rotations_x);
self.flags
.set(RigidBodyFlags::ROTATION_LOCKED_Y, !allow_rotations_y);
self.flags
.set(RigidBodyFlags::ROTATION_LOCKED_Z, !allow_rotations_z);
self
}
/// Sets the additional mass of the rigid-body being built.
///
/// This is only the "additional" mass because the total mass of the rigid-body is
/// equal to the sum of this additional mass and the mass computed from the colliders
/// (with non-zero densities) attached to this rigid-body.
pub fn additional_mass(mut self, mass: Real) -> Self {
self.mass_properties.set_mass(mass, false);
self
}
/// Sets the additional mass of the rigid-body being built.
///
/// This is only the "additional" mass because the total mass of the rigid-body is
/// equal to the sum of this additional mass and the mass computed from the colliders
/// (with non-zero densities) attached to this rigid-body.
#[deprecated(note = "renamed to `additional_mass`.")]
pub fn mass(self, mass: Real) -> Self {
self.additional_mass(mass)
}
/// Sets the additional angular inertia of this rigid-body.
///
/// This is only the "additional" angular inertia because the total angular inertia of
/// the rigid-body is equal to the sum of this additional value and the angular inertia
/// computed from the colliders (with non-zero densities) attached to this rigid-body.
#[cfg(feature = "dim2")]
pub fn additional_principal_angular_inertia(mut self, inertia: Real) -> Self {
self.mass_properties.inv_principal_inertia_sqrt =
utils::inv(ComplexField::sqrt(inertia.max(0.0)));
self
}
/// Sets the angular inertia of this rigid-body.
#[cfg(feature = "dim2")]
#[deprecated(note = "renamed to `additional_principal_angular_inertia`.")]
pub fn principal_angular_inertia(self, inertia: Real) -> Self {
self.additional_principal_angular_inertia(inertia)
}
/// Use `self.principal_angular_inertia` instead.
#[cfg(feature = "dim2")]
#[deprecated(note = "renamed to `additional_principal_angular_inertia`.")]
pub fn principal_inertia(self, inertia: Real) -> Self {
self.additional_principal_angular_inertia(inertia)
}
/// Sets the additional principal angular inertia of this rigid-body.
///
/// This is only the "additional" angular inertia because the total angular inertia of
/// the rigid-body is equal to the sum of this additional value and the angular inertia
/// computed from the colliders (with non-zero densities) attached to this rigid-body.
#[cfg(feature = "dim3")]
pub fn additional_principal_angular_inertia(mut self, inertia: AngVector<Real>) -> Self {
self.mass_properties.inv_principal_inertia_sqrt =
inertia.map(|e| utils::inv(ComplexField::sqrt(e.max(0.0))));
self
}
/// Sets the principal angular inertia of this rigid-body.
#[cfg(feature = "dim3")]
#[deprecated(note = "renamed to `additional_principal_angular_inertia`.")]
pub fn principal_angular_inertia(self, inertia: AngVector<Real>) -> Self {
self.additional_principal_angular_inertia(inertia)
}
/// Use `self.principal_angular_inertia` instead.
#[cfg(feature = "dim3")]
#[deprecated(note = "renamed to `additional_principal_angular_inertia`.")]
pub fn principal_inertia(self, inertia: AngVector<Real>) -> Self {
self.additional_principal_angular_inertia(inertia)
}
/// Sets the damping factor for the linear part of the rigid-body motion.
///
/// The higher the linear damping factor is, the more quickly the rigid-body
/// will slow-down its translational movement.
pub fn linear_damping(mut self, factor: Real) -> Self {
self.linear_damping = factor;
self
}
/// Sets the damping factor for the angular part of the rigid-body motion.
///
/// The higher the angular damping factor is, the more quickly the rigid-body
/// will slow-down its rotational movement.
pub fn angular_damping(mut self, factor: Real) -> Self {
self.angular_damping = factor;
self
}
/// Sets the initial linear velocity of the rigid-body to be created.
#[cfg(feature = "dim2")]
pub fn linvel(mut self, x: Real, y: Real) -> Self {
self.linvel = Vector::new(x, y);
self
}
/// Sets the initial linear velocity of the rigid-body to be created.
#[cfg(feature = "dim3")]
pub fn linvel(mut self, x: Real, y: Real, z: Real) -> Self {
self.linvel = Vector::new(x, y, z);
self
}
/// Sets the initial angular velocity of the rigid-body to be created.
pub fn angvel(mut self, angvel: AngVector<Real>) -> Self {
self.angvel = angvel;
self
}
/// Sets whether or not the rigid-body to be created can sleep if it reaches a dynamic equilibrium.
pub fn can_sleep(mut self, can_sleep: bool) -> Self {
self.can_sleep = can_sleep;
self
}
/// Enabled continuous collision-detection for this rigid-body.
pub fn ccd_enabled(mut self, enabled: bool) -> Self {
self.ccd_enabled = enabled;
self
}
/// Sets whether or not the rigid-body is to be created asleep.
pub fn sleeping(mut self, sleeping: bool) -> Self {
self.sleeping = sleeping;
self
}
/// Build a new rigid-body with the parameters configured with this builder.
pub fn build(&self) -> RigidBody {
let mut rb = RigidBody::new();
rb.next_position = self.position; // FIXME: compute the correct value?
rb.position = self.position;
rb.linvel = self.linvel;
rb.angvel = self.angvel;
rb.body_status = self.body_status;
rb.user_data = self.user_data;
rb.mass_properties = self.mass_properties;
rb.linear_damping = self.linear_damping;
rb.angular_damping = self.angular_damping;
rb.gravity_scale = self.gravity_scale;
rb.flags = self.flags;
rb.dominance_group = self.dominance_group;
rb.enable_ccd(self.ccd_enabled);
if self.can_sleep && self.sleeping {
rb.sleep();
}
if !self.can_sleep {
rb.activation.threshold = -1.0;
}
rb
}
}
/// The activation status of a body.
///
/// This controls whether a body is sleeping or not.
/// If the threshold is negative, the body never sleeps.
#[derive(Copy, Clone, Debug)]
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
pub struct ActivationStatus {
/// The threshold pseudo-kinetic energy bellow which the body can fall asleep.
pub threshold: Real,
/// The current pseudo-kinetic energy of the body.
pub energy: Real,
/// Is this body already sleeping?
pub sleeping: bool,
}
impl ActivationStatus {
/// The default amount of energy bellow which a body can be put to sleep by nphysics.
pub fn default_threshold() -> Real {
0.01
}
/// Create a new activation status initialised with the default activation threshold and is active.
pub fn new_active() -> Self {
ActivationStatus {
threshold: Self::default_threshold(),
energy: Self::default_threshold() * 4.0,
sleeping: false,
}
}
/// Create a new activation status initialised with the default activation threshold and is inactive.
pub fn new_inactive() -> Self {
ActivationStatus {
threshold: Self::default_threshold(),
energy: 0.0,
sleeping: true,
}
}
/// Returns `true` if the body is not asleep.
#[inline]
pub fn is_active(&self) -> bool {
self.energy != 0.0
}
}