Godot Ray-casting tutorial: Create a simple Hitscan Weapon

Introduction

In this tutorial, we will learn how to create a simple hitscan weapon in Godot using raycasting. Raycasting is an essential technique that allows us to detect collisions and interactions in 3D space. By the end of this tutorial, you will understand how to implement raycasting using the PhysicsRayQueryParameters3D class in Godot 4, which is particularly useful for various gameplay mechanics, such as enemy vision and shooting mechanics.

Step 1: Setting Up the Environment

1. Download and Install Godot 4:

   • Ensure you have Godot 4 installed on your computer. You can download it from the official Godot website.

2. Create a New Project:

   • Open Godot and create a new project.
   • Choose a suitable name and location for your project.

3. Set Up a 3D Scene:

   • Create a new 3D scene.
   • Add a Camera node to your scene, ensuring it's positioned to view the area where you will implement the hitscan weapon.

Step 2: Adding the Hitscan Weapon Script

1. Create a New Script:

   • Select the Camera node and add a new script to it. Name it HitscanWeapon.gd.

2. Implementing the Raycast Logic:

   • Open your newly created script and start coding the raycasting logic. Use the following code snippet as a starting point:

   extends Camera
   
   var ray_length = 100  # Define how far the ray will cast
   
   func _process(delta)
       if Input.is_action_just_pressed("shoot")
           shoot()
   
   func shoot()
       var space_state = get_world_3d().direct_space_state
       var ray_origin = global_transform.origin
       var ray_direction = -transform.basis.z  # Cast ray forward from the camera
       var raycast_params = PhysicsRayQueryParameters3D.new()
   
       raycast_params.from = ray_origin
       raycast_params.to = ray_origin + ray_direction * ray_length
   
       var result = space_state.intersect_ray(raycast_params)
       if result
           print("Hit: ", result)
   

3. Understanding the Code:

   • ray_length defines how far the ray will travel.
   • The shoot function is called when the shoot action is triggered.
   • intersect_ray performs the raycasting and returns the collision information if there’s a hit.

Step 3: Configuring Input Actions

1. Setting Up Input Actions:

   • Go to the "Project" menu and select "Project Settings."
   • Navigate to the "Input Map" tab.
   • Add a new action called shoot and bind it to a key of your choice (e.g., left mouse button).

2. Testing the Input:

   • Ensure your input configuration works by running the scene and pressing the designated key to trigger the shoot action.

Step 4: Visual Feedback

1. Adding Visual Effects:

   • To give feedback when a hit occurs, consider adding a simple particle system or a sound effect.
   • You can instantiate a Particles3D node in your scene and play it upon a successful hit detection.

2. Modifying the shoot Function:

   • Update the shoot function to include visual feedback:

   func shoot()

   var space_state = get_world_3d().direct_space_state var ray_origin = global_transform.origin var ray_direction = -transform.basis.z var raycast_params = PhysicsRayQueryParameters3D.new() raycast_params.from = ray_origin raycast_params.to = ray_origin + ray_direction * ray_length var result = space_state.intersect_ray(raycast_params)

   if result

   print("Hit: ", result) # Play particle effect or sound here

Conclusion

In this tutorial, we covered the basics of creating a hitscan weapon in Godot using raycasting. You learned how to set up a project, implement raycasting logic, configure input actions, and provide visual feedback upon hitting an object.

As a next step, consider expanding on this foundation by:

• Implementing different types of weapons.
• Adding enemy AI that responds to the player's actions.
• Exploring other applications of raycasting in your game, such as detecting line of sight for NPCs.

Feel free to experiment with the code and customize it further to fit your game's needs!