Godot Shaders : An Introduction

Introduction

This tutorial serves as an introduction to shaders in Godot, particularly for beginners. We will cover the basics of creating shaders for 2D graphics, culminating in a 2D water shader. By the end, you'll have a foundational understanding of how to work with shaders in Godot, which can enhance your game visuals significantly.

Step 1: Setting Up Your Godot Project

• Open Godot and create a new project.
• Choose a suitable project name and location.
• Select the 2D mode since we will focus on 2D shaders.
• Once the project loads, create a new scene and add a Node2D as the root.

Step 2: Creating a Shader

• Right-click on the Node2D in the scene tree and select Add Child Node.
• Choose Sprite as the child node.
• In the Inspector panel, look for the Material property.
• Click on the empty field next to Material and select New ShaderMaterial.
• Click on the newly created ShaderMaterial and then click on Shader to create a new shader.

Step 3: Writing Your First Shader Code

• In the shader editor, start with a basic shader structure:

  shader_type canvas_item;
  
  void fragment() {
      COLOR = vec4(1.0, 0.0, 0.0, 1.0); // This will display a solid red color
  }
  

• Save your shader and return to the scene. You should see a red sprite on your screen.

Step 4: Adding Texture to the Shader

• Replace the solid color in the shader code with a texture.
• Modify the fragment function as follows:

  uniform sampler2D my_texture;
  
  void fragment() {
      vec2 uv = UV; // Get the UV coordinates
      COLOR = texture(my_texture, uv); // Use the texture
  }
  

• Back in the Inspector, assign a texture to the my_texture uniform in the ShaderMaterial settings.

Step 5: Creating a 2D Water Shader

• To create a water effect, we will modify the shader to simulate movement.
• Update your shader code to include a sine wave for the water effect:

  uniform sampler2D my_texture;
  uniform float time;
  
  void fragment() {
      vec2 uv = UV;
      uv.y += sin(uv.x * 10.0 + time) * 0.05; // Create wave effect
      COLOR = texture(my_texture, uv);
  }
  

• Ensure you update the time uniform from your script. In your Node2D script, add:

  func _process(delta):
      $Sprite.material.set_shader_param("time", OS.get_ticks_msec() / 1000.0);
  

Step 6: Testing and Adjusting Your Shader

• Run your project to see the water shader in action.
• Experiment with the wave parameters (frequency and amplitude) to achieve the desired effect.
• Adjust the speed of the wave by modifying the time variable's influence.

Conclusion

You have successfully created your first shader in Godot and applied it to create a water effect. Shaders can greatly enhance the visual quality of your 2D games. Continue experimenting with different effects, such as lighting and gradients, to expand your skills. Consider exploring more complex shader tutorials or diving into 3D shaders for your future projects. Happy coding!