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

game/src/systems/physics.rs

@@ -0,0 +1,34 @@
+use raidillon_core::scene::Scene;
+use raidillon_ecs::components::RigidBodyComponent;
+use raidillon_ecs::Transform;
+use raidillon_engine::EngineResources;
+use raidillon_engine::system::System;
+use raidillon_physics::Physics;
+use raidillon_platform::PlatformContext;
+
+#[derive(Default)]
+pub struct PhysicsSystem;
+
+impl System for PhysicsSystem {
+    fn load_world(&mut self, res: &mut EngineResources, scene: &mut Scene) {
+        let p = Physics::default();
+        res.insert(p);
+    }
+
+    fn fixed_update(&mut self, res: &mut EngineResources, scene: &mut Scene) {
+        let pctx = res.get::<PlatformContext>().expect("PlatformContext missing").clone();
+        let physics = res.get_mut::<Physics>().expect("Physics missing");
+        physics.step(pctx.time_ctx.fixed_dt);
+
+        let mut query = scene.world.query::<(&mut Transform, &RigidBodyComponent)>();
+        for (_ent, (tr, rb_component)) in query.iter() {
+            if let Some(body) = physics.get_rigid_body(rb_component.0) {
+                let pos = body.position();
+                let translation = Physics::rapier_translation_to_glam(&pos.translation.vector);
+                let rotation = Physics::rapier_rotation_to_glam(&pos.rotation);
+                tr.translation = translation;
+                tr.rotation = rotation;
+            }
+        }
+    }
+}