Physics Support

- NEW CRATE: raidillon_physics.
- Added new models to be able to test the physics support.
- Added a new system "PhysicsSystem" to apply physics calculations to the ECS world.
- NEW COMPONENT: RigidBodyComponent

physics/src/physics.rs

@@ -0,0 +1,82 @@
+use glam::{Quat, Vec3};
+use rapier3d::na::{Quaternion, UnitQuaternion};
+use rapier3d::prelude::*;
+use raidillon_ecs::Transform;
+
+/// Tiny wrapper around rapier3d.
+pub struct Physics {
+    rigid_body_set: RigidBodySet,
+    collider_set: ColliderSet,
+    physics_pipeline: PhysicsPipeline,
+    island_manager: IslandManager,
+    broad_phase: DefaultBroadPhase,
+    narrow_phase: NarrowPhase,
+    impulse_joint_set: ImpulseJointSet,
+    multibody_joint_set: MultibodyJointSet,
+    ccd_solver: CCDSolver,
+    gravity: Vector<f32>,
+    integration_parameters: IntegrationParameters,
+}
+
+impl Default for Physics {
+    fn default() -> Self {
+        Self {
+            gravity: vector![0.0, -9.81, 0.0],
+            rigid_body_set: Default::default(),
+            collider_set: Default::default(),
+            physics_pipeline: Default::default(),
+            island_manager: Default::default(),
+            broad_phase: Default::default(),
+            narrow_phase: Default::default(),
+            impulse_joint_set: Default::default(),
+            multibody_joint_set: Default::default(),
+            ccd_solver: Default::default(),
+            integration_parameters: Default::default(),
+        }
+    }
+}
+
+impl Physics {
+    pub fn step(&mut self, dt: f32) {
+        self.integration_parameters.dt = dt;
+        self.physics_pipeline.step(
+            &self.gravity,
+            &self.integration_parameters,
+            &mut self.island_manager,
+            &mut self.broad_phase,
+            &mut self.narrow_phase,
+            &mut self.rigid_body_set,
+            &mut self.collider_set,
+            &mut self.impulse_joint_set,
+            &mut self.multibody_joint_set,
+            &mut self.ccd_solver,
+            &(),
+            &(),
+        );
+    }
+
+    pub fn add_rigid_body(&mut self, kind: RigidBodyType, transform: Transform, collider: Collider) -> RigidBodyHandle {
+        let rb = RigidBodyBuilder::new(kind)
+            .translation(vector![transform.translation.x, transform.translation.y, transform.translation.z])
+            .build();
+        let rb_handle = self.rigid_body_set.insert(rb);
+        self.collider_set.insert_with_parent(collider, rb_handle, &mut self.rigid_body_set);
+        rb_handle
+    }
+
+    pub fn get_rigid_body(&self, handle: RigidBodyHandle) -> Option<&RigidBody> {
+        self.rigid_body_set.get(handle)
+    }
+
+    pub fn get_rigid_body_mut(&mut self, handle: RigidBodyHandle) -> Option<&mut RigidBody> {
+        self.rigid_body_set.get_mut(handle)
+    }
+
+    pub fn rapier_translation_to_glam(v: &Vector<f32>) -> Vec3 {
+        Vec3::new(v.x, v.y, v.z)
+    }
+
+    pub fn rapier_rotation_to_glam(r: &UnitQuaternion<f32>) -> Quat {
+        Quat::from_xyzw(r.i, r.j, r.k, r.w)
+    }
+}