问Libgdx3D中的RayCasting

EN

private static final Vector3 rayFrom = new Vector3();
private static final Vector3 rayTo = new Vector3();
private static final ClosestRayResultCallback callback = new ClosestRayResultCallback(rayFrom, rayTo);

public static btCollisionObject rayTest(btCollisionWorld collisionWorld, Ray ray) {
    rayFrom.set(ray.origin);
    // 50 meters max from the origin
    rayTo.set(ray.direction).scl(50f).add(rayFrom);

    // we reuse the ClosestRayResultCallback, thus we need to reset its
    // values
    callback.setCollisionObject(null);
    callback.setClosestHitFraction(1f);
    callback.getRayFromWorld().setValue(rayFrom.x, rayFrom.y, rayFrom.z);
    callback.getRayToWorld().setValue(rayTo.x, rayTo.y, rayTo.z);

    collisionWorld.rayTest(rayFrom, rayTo, callback);

    if (callback.hasHit()) {
        return callback.getCollisionObject();
    }

    return null;
}

public class BulletInputProcessor extends InputAdapter {

    private Viewport pickingViewport;
    private btCollisionWorld collisionWorld;

    // a constructor which takes a Viewport and the collision world and stores them
    public BulletInputProcessor(...) { ... }

    @Override
    public boolean touchUp(int screenX, int screenY, int pointer, int button) {
        if (button == Input.Buttons.LEFT) {
            Ray pickRay = pickingViewport.getPickRay(screenX, screenY);

            btCollisionObject body = BulletUtil.rayTest(collisionWorld, pickRay);
            if (body != null) {
                // do whatever you want with this body now
                return true;
            }
        }

        return false;
    }
}

callback.getRayFromWorld().setValue(rayFrom.x, rayFrom.y, rayFrom.z);
callback.getRayToWorld().setValue(rayTo.x, rayTo.y, rayTo.z);

  Vector3 rayFromWorld = new Vector3();
  rayFromWorld.set(rayFrom.x, rayFrom.y, rayFrom.z);
  Vector3 rayToWorld   = new Vector3();
  rayToWorld.set(rayTo.x, rayTo.y, rayTo.z);

btCollisionObject target = CollisionUtils.rayTest(dynamicsWorld, ray);
//test for collisionflags and stuff here
//and if your target is instance of btRigidBody
btRigidBody body = (btRigidBody)target;
body.activate();
body.applyCentralForce(ray.direction.scl(50000));