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Diffstat (limited to 'src/pipeline')
| -rw-r--r-- | src/pipeline/physics_hooks.rs | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/src/pipeline/physics_hooks.rs b/src/pipeline/physics_hooks.rs new file mode 100644 index 0000000..12b658f --- /dev/null +++ b/src/pipeline/physics_hooks.rs @@ -0,0 +1,146 @@ +use crate::dynamics::RigidBody; +use crate::geometry::{Collider, ColliderHandle, ContactManifold, SolverContact, SolverFlags}; + +/// Context given to custom collision filters to filter-out collisions. +pub struct PairFilterContext<'a> { + /// The first collider involved in the potential collision. + pub rigid_body1: &'a RigidBody, + /// The first collider involved in the potential collision. + pub rigid_body2: &'a RigidBody, + /// The first collider involved in the potential collision. + pub collider_handle1: ColliderHandle, + /// The first collider involved in the potential collision. + pub collider_handle2: ColliderHandle, + /// The first collider involved in the potential collision. + pub collider1: &'a Collider, + /// The first collider involved in the potential collision. + pub collider2: &'a Collider, +} + +pub struct ContactModificationContext<'a> { + /// The first collider involved in the potential collision. + pub rigid_body1: &'a RigidBody, + /// The first collider involved in the potential collision. + pub rigid_body2: &'a RigidBody, + /// The first collider involved in the potential collision. + pub collider_handle1: ColliderHandle, + /// The first collider involved in the potential collision. + pub collider_handle2: ColliderHandle, + /// The first collider involved in the potential collision. + pub collider1: &'a Collider, + /// The first collider involved in the potential collision. + pub collider2: &'a Collider, + /// The contact manifold. + pub manifold: &'a ContactManifold, + /// The solver contacts that can be modified. + pub solver_contacts: &'a mut Vec<SolverContact>, + /// User-defined data attached to the manifold. + // NOTE: we keep this a &'a mut u32 to emphasize the + // fact that this can be modified. + pub user_data: &'a mut u32, +} + +bitflags::bitflags! { + #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))] + /// Flags affecting the behavior of the constraints solver for a given contact manifold. + pub struct PhysicsHooksFlags: u32 { + /// If set, Rapier will call `PhysicsHooks::filter_contact_pair` whenever relevant. + const FILTER_CONTACT_PAIR = 0b0001; + /// If set, Rapier will call `PhysicsHooks::filter_intersection_pair` whenever relevant. + const FILTER_INTERSECTION_PAIR = 0b0010; + /// If set, Rapier will call `PhysicsHooks::modify_solver_contact` whenever relevant. + const MODIFY_SOLVER_CONTACTS = 0b0100; + } +} + +/// User-defined functions called by the physics engines during one timestep in order to customize its behavior. +pub trait PhysicsHooks: Send + Sync { + /// The sets of hooks that must be taken into account. + fn active_hooks(&self) -> PhysicsHooksFlags; + + /// Applies the contact pair filter. + /// + /// Note that this method will only be called if `self.active_hooks()` + /// contains the `PhysicsHooksFlags::FILTER_CONTACT_PAIR` flags. + /// + /// User-defined filter for potential contact pairs detected by the broad-phase. + /// This can be used to apply custom logic in order to decide whether two colliders + /// should have their contact computed by the narrow-phase, and if these contact + /// should be solved by the constraints solver + /// + /// Note that using a contact pair filter will replace the default contact filtering + /// which consists of preventing contact computation between two non-dynamic bodies. + /// + /// This filtering method is called after taking into account the colliders collision groups. + /// + /// If this returns `None`, then the narrow-phase will ignore this contact pair and + /// not compute any contact manifolds for it. + /// If this returns `Some`, then the narrow-phase will compute contact manifolds for + /// this pair of colliders, and configure them with the returned solver flags. For + /// example, if this returns `Some(SolverFlags::COMPUTE_IMPULSES)` then the contacts + /// will be taken into account by the constraints solver. If this returns + /// `Some(SolverFlags::empty())` then the constraints solver will ignore these + /// contacts. + fn filter_contact_pair(&self, context: &PairFilterContext) -> Option<SolverFlags>; + + /// Applies the intersection pair filter. + /// + /// Note that this method will only be called if `self.active_hooks()` + /// contains the `PhysicsHooksFlags::FILTER_INTERSECTION_PAIR` flags. + /// + /// User-defined filter for potential intersection pairs detected by the broad-phase. + /// + /// This can be used to apply custom logic in order to decide whether two colliders + /// should have their intersection computed by the narrow-phase. + /// + /// Note that using an intersection pair filter will replace the default intersection filtering + /// which consists of preventing intersection computation between two non-dynamic bodies. + /// + /// This filtering method is called after taking into account the colliders collision groups. + /// + /// If this returns `false`, then the narrow-phase will ignore this pair and + /// not compute any intersection information for it. + /// If this return `true` then the narrow-phase will compute intersection + /// information for this pair. + fn filter_intersection_pair(&self, context: &PairFilterContext) -> bool; + + /// Modifies the set of contacts seen by the constraints solver. + /// + /// Note that this method will only be called if `self.active_hooks()` + /// contains the `PhysicsHooksFlags::MODIFY_SOLVER_CONTACTS` flags. + /// + /// By default, the content of `solver_contacts` is computed from `manifold.points`. + /// This method will be called on each contact manifold which have the flag `SolverFlags::MODIFY_CONTACTS` set. + /// This method can be used to modify the set of solver contacts seen by the constraints solver: contacts + /// can be removed and modified. + /// + /// Note that if all the contacts have to be ignored by the constraint solver, you may simply + /// do `context.solver_contacts.clear()`. + /// + /// Modifying the solver contacts allow you to achieve various effects, including: + /// - Simulating conveyor belts by setting the `surface_velocity` of a solver contact. + /// - Simulating shapes with multiply materials by modifying the friction and restitution + /// coefficient depending of the features in contacts. + /// - Simulating one-way platforms depending on the contact normal. + /// + /// Each contact manifold is given a `u32` user-defined data that is persistent between + /// timesteps (as long as the contact manifold exists). This user-defined data is initialized + /// as 0 and can be modified in `context.user_data`. + fn modify_solver_contacts(&self, context: &mut ContactModificationContext); +} + +impl PhysicsHooks for () { + fn active_hooks(&self) -> PhysicsHooksFlags { + PhysicsHooksFlags::empty() + } + + fn filter_contact_pair(&self, _: &PairFilterContext) -> Option<SolverFlags> { + None + } + + fn filter_intersection_pair(&self, _: &PairFilterContext) -> bool { + false + } + + fn modify_solver_contacts(&self, _: &mut ContactModificationContext) {} +} |