Added Rapier example (mrdoob#25892)

* Added Rapier example.

* Updated screenshot.

* Fixed DeepScan issue.

* RapeirPhysics: Added world.timestep.

examples/files.json

@@ -391,7 +391,8 @@
 		"physics_ammo_rope",
 		"physics_ammo_terrain",
 		"physics_ammo_volume",
-		"physics_oimo_instancing"
+		"physics_oimo_instancing",
+		"physics_rapier_instancing"
 	],
 	"misc": [
 		"misc_animation_groups",

examples/jsm/physics/RapierPhysics.js

@@ -0,0 +1,237 @@
+async function RapierPhysics( path ) {
+
+	const RAPIER = await import( path );
+
+	await RAPIER.init();
+
+	const frameRate = 60;
+
+	// Docs: https://rapier.rs/docs/api/javascript/JavaScript3D/	
+
+	const gravity = { x: 0.0, y: - 9.81, z: 0.0 };
+    const world = new RAPIER.World( gravity );
+
+	function getCollider( geometry ) {
+
+		const parameters = geometry.parameters;
+
+		// TODO change type to is*
+
+		if ( geometry.type === 'BoxGeometry' ) {
+
+			const sx = parameters.width !== undefined ? parameters.width / 2 : 0.5;
+			const sy = parameters.height !== undefined ? parameters.height / 2 : 0.5;
+			const sz = parameters.depth !== undefined ? parameters.depth / 2 : 0.5;
+
+			return RAPIER.ColliderDesc.cuboid( sx, sy, sz );
+
+		} else if ( geometry.type === 'SphereGeometry' || geometry.type === 'IcosahedronGeometry' ) {
+
+			const radius = parameters.radius !== undefined ? parameters.radius : 1;
+
+			return RAPIER.ColliderDesc.ball( radius );
+
+		}
+
+		return null;
+
+	}
+
+	const meshes = [];
+	const meshMap = new WeakMap();
+
+	function addMesh( mesh, mass = 0, restitution = 0 ) {
+
+		const shape = getCollider( mesh.geometry );
+
+		if ( shape !== null ) {
+
+			shape.setMass( mass );
+			shape.setRestitution( restitution );
+
+			if ( mesh.isInstancedMesh ) {
+
+				handleInstancedMesh( mesh, mass, shape );
+
+			} else if ( mesh.isMesh ) {
+
+				handleMesh( mesh, mass, shape );
+
+			}
+
+		}
+
+	}
+
+	function handleMesh( mesh, mass, shape ) {
+
+		const position = mesh.position;
+		const quaternion = mesh.quaternion;
+
+		const desc = mass > 0 ? RAPIER.RigidBodyDesc.dynamic() : RAPIER.RigidBodyDesc.fixed();
+		desc.setTranslation( position.x, position.y, position.z );
+		desc.setRotation( quaternion );
+
+		const body = world.createRigidBody( desc );
+		world.createCollider( shape, body );
+
+		if ( mass > 0 ) {
+
+			meshes.push( mesh );
+			meshMap.set( mesh, body );
+
+		}
+
+	}
+
+	function handleInstancedMesh( mesh, mass, shape ) {
+
+		const array = mesh.instanceMatrix.array;
+
+		const bodies = [];
+
+		for ( let i = 0; i < mesh.count; i ++ ) {
+
+			const index = i * 16;
+
+			const desc = mass > 0 ? RAPIER.RigidBodyDesc.dynamic() : RAPIER.RigidBodyDesc.fixed();
+			desc.setTranslation( array[ index + 12 ], array[ index + 13 ], array[ index + 14 ] );
+
+			const body = world.createRigidBody( desc );
+			world.createCollider( shape, body );
+
+			bodies.push( body );
+
+		}
+
+		if ( mass > 0 ) {
+
+			meshes.push( mesh );
+			meshMap.set( mesh, bodies );
+
+		}
+
+	}
+
+	const vector = { x: 0, y: 0, z: 0 };
+
+	function setMeshPosition( mesh, position, index = 0 ) {
+
+		if ( mesh.isInstancedMesh ) {
+
+			const bodies = meshMap.get( mesh );
+			const body = bodies[ index ];
+
+			body.setAngvel( vector );
+			body.setLinvel( vector );
+			body.setTranslation( position );
+
+		} else if ( mesh.isMesh ) {
+
+			const body = meshMap.get( mesh );
+
+			body.setAngvel( vector );
+			body.setLinvel( vector );
+			body.setTranslation( position );
+
+		}
+
+	}
+
+	//
+
+	let lastTime = 0;
+
+	function step() {
+
+		const time = performance.now();
+
+		if ( lastTime > 0 ) {
+
+			const delta = ( time - lastTime ) / 1000;
+
+			world.timestep = delta;
+			world.step();
+
+			for ( let i = 0, l = meshes.length; i < l; i ++ ) {
+
+				const mesh = meshes[ i ];
+
+				if ( mesh.isInstancedMesh ) {
+
+					const array = mesh.instanceMatrix.array;
+					const bodies = meshMap.get( mesh );
+
+					for ( let j = 0; j < bodies.length; j ++ ) {
+
+						const body = bodies[ j ];
+
+						const position = body.translation();
+						const quaternion = body.rotation();
+
+						compose( position, quaternion, array, j * 16 );
+
+					}
+
+					mesh.instanceMatrix.needsUpdate = true;
+					mesh.computeBoundingSphere();
+
+				} else if ( mesh.isMesh ) {
+
+					const body = meshMap.get( mesh );
+
+					mesh.position.copy( body.translation() );
+					mesh.quaternion.copy( body.rotation() );
+
+				}
+
+			}
+
+		}
+
+		lastTime = time;
+
+	}
+
+	// animate
+
+	setInterval( step, 1000 / frameRate );
+
+	return {
+		addMesh: addMesh,
+		setMeshPosition: setMeshPosition
+	};
+
+}
+
+function compose( position, quaternion, array, index ) {
+
+	const x = quaternion.x, y = quaternion.y, z = quaternion.z, w = quaternion.w;
+	const x2 = x + x, y2 = y + y, z2 = z + z;
+	const xx = x * x2, xy = x * y2, xz = x * z2;
+	const yy = y * y2, yz = y * z2, zz = z * z2;
+	const wx = w * x2, wy = w * y2, wz = w * z2;
+
+	array[ index + 0 ] = ( 1 - ( yy + zz ) );
+	array[ index + 1 ] = ( xy + wz );
+	array[ index + 2 ] = ( xz - wy );
+	array[ index + 3 ] = 0;
+
+	array[ index + 4 ] = ( xy - wz );
+	array[ index + 5 ] = ( 1 - ( xx + zz ) );
+	array[ index + 6 ] = ( yz + wx );
+	array[ index + 7 ] = 0;
+
+	array[ index + 8 ] = ( xz + wy );
+	array[ index + 9 ] = ( yz - wx );
+	array[ index + 10 ] = ( 1 - ( xx + yy ) );
+	array[ index + 11 ] = 0;
+
+	array[ index + 12 ] = position.x;
+	array[ index + 13 ] = position.y;
+	array[ index + 14 ] = position.z;
+	array[ index + 15 ] = 1;
+
+}
+
+export { RapierPhysics };