RapierPhysics: Add heightfield support. (#30906)

* Add rapier terrain physics example

* Add screenshot (same as ammo version) and entry to files.json for physics_rapier_terrain

* fix linting error by removing unused variable declaration

* Responding to PR feedback

Use RapierPhysics instead of direct Rapier in example. Update RapierPhysics with addHeightfield.

* Fix CodeQL notice - remove unused function

* Update physics_rapier_terrain.html

Clean up code style.

* Update RapierPhysics.js

* Update RapierPhysics.js

---------

Co-authored-by: Michael Herzog <[email protected]>

Author: andytriboletti

examples/files.json

@@ -509,7 +509,9 @@
 		"physics_rapier_instancing",
 		"physics_rapier_joints",
 		"physics_rapier_character_controller",
-		"physics_rapier_vehicle_controller"
+		"physics_rapier_vehicle_controller",
+		"physics_rapier_terrain"
+
 	],
 	"misc": [
 		"misc_animation_groups",

examples/jsm/physics/RapierPhysics.js

@@ -31,14 +31,14 @@ function getShape( geometry ) {
 	} else if ( geometry.type === 'CylinderGeometry' ) {
 
 		const radius = parameters.radiusBottom !== undefined ? parameters.radiusBottom : 0.5;
-		const length = parameters.length !== undefined ? parameters.length : 0.5;
+		const length = parameters.height !== undefined ? parameters.height : 0.5;
 
 		return RAPIER.ColliderDesc.cylinder( length / 2, radius );
 
 	} else if ( geometry.type === 'CapsuleGeometry' ) {
 
 		const radius = parameters.radius !== undefined ? parameters.radius : 0.5;
-		const length = parameters.length !== undefined ? parameters.length : 0.5;
+		const length = parameters.height !== undefined ? parameters.height : 0.5;
 
 		return RAPIER.ColliderDesc.capsule( length / 2, radius );
 
@@ -209,6 +209,24 @@ async function RapierPhysics() {
 
 	}
 
+	function addHeightfield( mesh, width, depth, heights, scale ) {
+
+		const shape = RAPIER.ColliderDesc.heightfield( width, depth, heights, scale );
+		
+		const bodyDesc = RAPIER.RigidBodyDesc.fixed();
+		bodyDesc.setTranslation( mesh.position.x, mesh.position.y, mesh.position.z );
+		bodyDesc.setRotation( mesh.quaternion );
+		
+		const body = world.createRigidBody( bodyDesc );
+		world.createCollider( shape, body );
+		
+		if ( ! mesh.userData.physics ) mesh.userData.physics = {};
+		mesh.userData.physics.body = body;
+		
+		return body;
+
+	}
+
 	//
 
 	const clock = new Clock();
@@ -309,7 +327,25 @@ async function RapierPhysics() {
 		 * @param {Vector3} velocity - The new velocity.
 		 * @param {number} [index=0] - If the mesh is instanced, the index represents the instanced ID.
 		 */
-		setMeshVelocity: setMeshVelocity
+		setMeshVelocity: setMeshVelocity,
+
+		/**
+		 * Adds a heightfield terrain to the physics simulation.
+		 * 
+		 * @method
+		 * @name RapierPhysics#addHeightfield
+		 * @param {Mesh} mesh - The Three.js mesh representing the terrain.
+		 * @param {number} width - The number of vertices along the width (x-axis) of the heightfield.
+		 * @param {number} depth - The number of vertices along the depth (z-axis) of the heightfield.
+		 * @param {Float32Array} heights - Array of height values for each vertex in the heightfield.
+		 * @param {Object} scale - Scale factors for the heightfield dimensions.
+		 * @param {number} scale.x - Scale factor for width.
+		 * @param {number} scale.y - Scale factor for height.
+		 * @param {number} scale.z - Scale factor for depth.
+		 * @returns {RigidBody} The created Rapier rigid body for the heightfield.
+		 */
+		addHeightfield: addHeightfield
+
 	};
 
 }