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Add a simpler to lock the rotation or translation of a dynamic rigid-body.

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This commit is contained in:
Crozet Sébastien
2020-11-30 15:26:22 +01:00
parent c9ac149b17
commit c3e951f896
4 changed files with 214 additions and 14 deletions
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2
examples3d/all_examples3.rs
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@@ -26,6 +26,7 @@ mod fountain3;
mod heightfield3;
mod joints3;
mod keva3;
mod locked_rotation3;
mod platform3;
mod primitives3;
mod restitution3;
@@ -78,6 +79,7 @@ pub fn main() {
("Domino", domino3::init_world),
("Heightfield", heightfield3::init_world),
("Joints", joints3::init_world),
("Locked rotations", locked_rotation3::init_world),
("Platform", platform3::init_world),
("Restitution", restitution3::init_world),
("Stacks", stacks3::init_world),

66
examples3d/locked_rotation3.rs Normal file
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@@ -0,0 +1,66 @@
use na::{Point3, Vector3};
use rapier3d::dynamics::{JointSet, RigidBodyBuilder, RigidBodySet};
use rapier3d::geometry::{ColliderBuilder, ColliderSet};
use rapier_testbed3d::Testbed;
// This shows a bug when a cylinder is in contact with a very large
// but very thin cuboid. In this case the EPA returns an incorrect
// contact normal, resulting in the cylinder falling through the floor.
pub fn init_world(testbed: &mut Testbed) {
/*
* World
*/
let mut bodies = RigidBodySet::new();
let mut colliders = ColliderSet::new();
let joints = JointSet::new();
/*
* The ground
*/
let ground_size = 5.0;
let ground_height = 0.1;
let rigid_body = RigidBodyBuilder::new_static()
.translation(0.0, -ground_height, 0.0)
.build();
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::cuboid(ground_size, ground_height, ground_size).build();
colliders.insert(collider, handle, &mut bodies);
/*
* A rectangle that only rotates along the `x` axis.
*/
let rigid_body = RigidBodyBuilder::new_dynamic()
.translation(0.0, 3.0, 0.0)
.lock_translations()
.principal_inertia(Vector3::zeros(), Vector3::new(false, true, true))
.build();
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::cuboid(0.2, 0.6, 2.0).build();
colliders.insert(collider, handle, &mut bodies);
/*
* A capsule that cannot rotate.
* We initialize it in a tilted position to demonstrate the
* fact that is cannot rotate.
*/
let rigid_body = RigidBodyBuilder::new_dynamic()
.translation(0.0, 5.0, 0.0)
.rotation(Vector3::x() * 1.0)
.lock_rotations()
.build();
let handle = bodies.insert(rigid_body);
let collider = ColliderBuilder::capsule_y(0.6, 0.4).build();
colliders.insert(collider, handle, &mut bodies);
/*
* Set up the testbed.
*/
testbed.set_world(bodies, colliders, joints);
testbed.look_at(Point3::new(10.0, 3.0, 0.0), Point3::new(0.0, 3.0, 0.0));
}
fn main() {
let testbed = Testbed::from_builders(0, vec![("Boxes", init_world)]);
testbed.run()
}

158
src/dynamics/rigid_body.rs
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@@ -3,7 +3,7 @@ use crate::geometry::{
Collider, ColliderHandle, ColliderSet, InteractionGraph, RigidBodyGraphIndex,
};
use crate::math::{AngVector, AngularInertia, Isometry, Point, Rotation, Translation, Vector};
use crate::utils::{WCross, WDot};
use crate::utils::{self, WCross, WDot};
use num::Zero;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
@@ -25,6 +25,17 @@ pub enum BodyStatus {
// 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 IGNORE_COLLIDER_MASS = 1 << 0;
const IGNORE_COLLIDER_ANGULAR_INERTIA_X = 1 << 1;
const IGNORE_COLLIDER_ANGULAR_INERTIA_Y = 1 << 2;
const IGNORE_COLLIDER_ANGULAR_INERTIA_Z = 1 << 3;
}
}
bitflags::bitflags! {
#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
/// Flags affecting the behavior of the constraints solver for a given contact manifold.
@@ -46,7 +57,7 @@ pub struct RigidBody {
pub(crate) position: Isometry<f32>,
pub(crate) predicted_position: Isometry<f32>,
/// The local mass properties of the rigid-body.
pub mass_properties: MassProperties,
pub(crate) mass_properties: MassProperties,
/// The world-space center of mass of the rigid-body.
pub world_com: Point<f32>,
/// The square-root of the inverse angular inertia tensor of the rigid-body.
@@ -69,6 +80,7 @@ pub struct RigidBody {
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.
pub body_status: BodyStatus,
@@ -97,6 +109,7 @@ impl RigidBody {
active_set_id: 0,
active_set_offset: 0,
active_set_timestamp: 0,
flags: RigidBodyFlags::empty(),
changes: RigidBodyChanges::all(),
body_status: BodyStatus::Dynamic,
user_data: 0,
@@ -123,6 +136,12 @@ impl RigidBody {
}
}
/// The mass properties of this rigid-body.
#[inline]
pub fn mass_properties(&self) -> &MassProperties {
&self.mass_properties
}
/// The handles of colliders attached to this rigid body.
pub fn colliders(&self) -> &[ColliderHandle] {
&self.colliders[..]
@@ -153,7 +172,7 @@ impl RigidBody {
///
/// Returns zero if this rigid body has an infinite mass.
pub fn mass(&self) -> f32 {
crate::utils::inv(self.mass_properties.inv_mass)
utils::inv(self.mass_properties.inv_mass)
}
/// The predicted position of this rigid-body.
@@ -176,10 +195,40 @@ impl RigidBody {
.mass_properties()
.transform_by(coll.position_wrt_parent());
self.colliders.push(handle);
self.mass_properties += mass_properties;
self.mass_properties += Self::filter_collider_mass_props(mass_properties, self.flags);
self.update_world_mass_properties();
}
fn filter_collider_mass_props(
mut props: MassProperties,
flags: RigidBodyFlags,
) -> MassProperties {
if flags.contains(RigidBodyFlags::IGNORE_COLLIDER_MASS) {
props.inv_mass = 0.0;
}
#[cfg(feature = "dim2")]
{
if flags.contains(RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Z) {
props.inv_principal_inertia_sqrt = 0.0;
}
}
#[cfg(feature = "dim3")]
{
if flags.contains(RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_X) {
props.inv_principal_inertia_sqrt.x = 0.0;
}
if flags.contains(RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Y) {
props.inv_principal_inertia_sqrt.y = 0.0;
}
if flags.contains(RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Z) {
props.inv_principal_inertia_sqrt.z = 0.0;
}
}
props
}
pub(crate) fn update_colliders_positions(&mut self, colliders: &mut ColliderSet) {
for handle in &self.colliders {
let collider = &mut colliders[*handle];
@@ -196,7 +245,7 @@ impl RigidBody {
let mass_properties = coll
.mass_properties()
.transform_by(coll.position_wrt_parent());
self.mass_properties -= mass_properties;
self.mass_properties -= Self::filter_collider_mass_props(mass_properties, self.flags);
self.update_world_mass_properties();
}
}
@@ -491,6 +540,7 @@ pub struct RigidBodyBuilder {
linear_damping: f32,
angular_damping: f32,
body_status: BodyStatus,
flags: RigidBodyFlags,
mass_properties: MassProperties,
can_sleep: bool,
sleeping: bool,
@@ -507,6 +557,7 @@ impl RigidBodyBuilder {
linear_damping: 0.0,
angular_damping: 0.0,
body_status,
flags: RigidBodyFlags::empty(),
mass_properties: MassProperties::zero(),
can_sleep: true,
sleeping: false,
@@ -579,18 +630,98 @@ impl RigidBodyBuilder {
self
}
/// Prevents this rigid-body from translating because of forces.
///
/// This is equivalent to `self.mass(0.0, true)`. See the
/// documentation of [`RigidBodyBuilder::mass`] for more details.
pub fn lock_translations(mut self) -> Self {
self.mass(0.0, true)
}
/// Prevents this rigid-body from rotating because of forces.
///
/// This is equivalent to `self.principal_inertia(0.0, true)` (in 2D) or
/// `self.principal_inertia(Vector3::zeros(), Vector3::repeat(true))` (in 3D).
///
/// See the documentation of [`RigidBodyBuilder::principal_inertia`] for more details.
pub fn lock_rotations(mut self) -> Self {
#[cfg(feature = "dim2")]
return self.principal_inertia(0.0, true);
#[cfg(feature = "dim3")]
return self.principal_inertia(Vector::zeros(), Vector::repeat(true));
}
/// Sets the mass of the rigid-body being built.
///
/// Note that the final mass of the rigid-bodies depends
/// on the initial mass of the rigid-body (set by this method)
/// In order to lock the translations of this rigid-body (by
/// making them kinematic), call `.mass(0.0, true)`.
///
/// If `ignore_colliders` is `true`, then the mass specified here
/// will be the final mass of the rigid-body created by this builder.
/// If `ignore_colliders` is `false`, then the final mass of the rigid-body
/// will depends on the initial mass set by this method to which is added
/// the contributions of all the colliders with non-zero density attached to
/// this rigid-body.
pub fn mass(mut self, mass: f32, ignore_colliders: bool) -> Self {
self.mass_properties.inv_mass = utils::inv(mass);
self.flags
.set(RigidBodyFlags::IGNORE_COLLIDER_MASS, ignore_colliders);
self
}
/// Sets the angular inertia of this rigid-body.
///
/// In order to lock the rotations of this rigid-body (by
/// making them kinematic), call `.principal_inertia(0.0, true)`.
///
/// If `ignore_colliders` is `true`, then the principal inertia specified here
/// will be the final principal inertia of the rigid-body created by this builder.
/// If `ignore_colliders` is `false`, then the final principal of the rigid-body
/// will depend on the initial principal inertia set by this method to which is added
/// the contributions of all the colliders with non-zero density attached to this rigid-body.
#[cfg(feature = "dim2")]
pub fn principal_inertia(mut self, inertia: f32, ignore_colliders: bool) -> Self {
self.mass_properties.inv_principal_inertia_sqrt = utils::inv(inertia);
self.flags.set(
RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_X
| RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Y
| RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Z,
ignore_colliders,
);
self
}
/// Sets the principal angular inertia of this rigid-body.
///
/// In order to lock the rotations of this rigid-body (by
/// making them kinematic), call `.principal_inertia(Vector3::zeros(), Vector3::repeat(false))`.
///
/// If `ignore_colliders[i]` is `true`, then the principal inertia specified here
/// along the `i`-th local axis of the rigid-body, will be the final principal inertia along
/// the `i`-th local axis of the rigid-body created by this builder.
/// If `ignore_colliders[i]` is `false`, then the final principal of the rigid-body
/// along its `i`-th local axis will depend on the initial principal inertia 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 to be the final
/// mass of your rigid-body, don't attach colliders to it, or
/// only attach colliders with densities equal to zero.
pub fn mass(mut self, mass: f32) -> Self {
self.mass_properties.inv_mass = crate::utils::inv(mass);
#[cfg(feature = "dim3")]
pub fn principal_inertia(
mut self,
inertia: AngVector<f32>,
ignore_colliders: AngVector<bool>,
) -> Self {
self.mass_properties.inv_principal_inertia_sqrt = inertia.map(utils::inv);
self.flags.set(
RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_X,
ignore_colliders.x,
);
self.flags.set(
RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Y,
ignore_colliders.y,
);
self.flags.set(
RigidBodyFlags::IGNORE_COLLIDER_ANGULAR_INERTIA_Z,
ignore_colliders.z,
);
self
}
@@ -656,6 +787,7 @@ impl RigidBodyBuilder {
rb.mass_properties = self.mass_properties;
rb.linear_damping = self.linear_damping;
rb.angular_damping = self.angular_damping;
rb.flags = self.flags;
if self.can_sleep && self.sleeping {
rb.sleep();

2
src_testbed/nphysics_backend.rs
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@@ -158,7 +158,7 @@ impl NPhysicsWorld {
pub fn sync(&self, bodies: &mut RigidBodySet, colliders: &mut ColliderSet) {
for (rapier_handle, nphysics_handle) in self.rapier2nphysics.iter() {
let mut rb = bodies.get_mut(*rapier_handle).unwrap();
let rb = bodies.get_mut(*rapier_handle).unwrap();
let ra = self.bodies.rigid_body(*nphysics_handle).unwrap();
let pos = *ra.position();
rb.set_position(pos, false);