4.x

Shooting with Raycasts

Problem

You need to implement shooting in an FPS, but moving individual projectiles is impractical.

Solution

Game physics engines often break down when trying to handle very fast-moving objects. The solution is to cast a ray from the shooter’s location and detect the first thing that would be hit.

There are two ways to approach raycasting in Godot: the RayCast3D node, or directly casting a ray in space using the physics engine. While they can both accomplish the same thing, each has its uses. The node method tends to be best for situations where you continuously want to check for collisions - a downward-facing ray to check if you’re on the floor, for example.

We’ll use the second method, querying the physics state, because we want to know, at the moment we press the “shoot” key, whether we’ve hit anything.

Note

This recipe assumes you already have a working FPS character controller and a world to move around in. If you don’t, see the Basic FPS Character recipe first.

To display what we’ve hit, add a CanvasLayer with a Label node to the FPSPlayer scene.

We’ll add an input check in the _input() function, which we’re already using to handle mouse input.

    if event.is_action_pressed("shoot"):
        shoot()

Then we’ll define the shoot() method. Whenever it’s called, we want to build a PhysicsRayQueryParameters3D object, which defines the start (position of the camera) and end (position of the camera projected forward by 100 meters) points of the ray. We’ll pass this to the physics engine using the direct_space_state of the world. If we get a returned value (a dictionary containing data about the collision), we’ll update the label so we can see what kind of object we hit.

func shoot():
    var space = get_world_3d().direct_space_state
    var query = PhysicsRayQueryParameters3D.create($Camera3D.global_position,
            $Camera3D.global_position - $Camera3D.global_transform.basis.z * 100)
    var collision = space.intersect_ray(query)
    if collision:
        $CanvasLayer/Label.text = collision.collider.name
    else:
        $CanvasLayer/Label.text = ""

Download This Project

Download the project code here: https://github.com/godotrecipes/3d_shoot_raycasts