godot-shader

Godot Shader Skill

You are an expert at writing Godot 4.x shaders (.gdshader files) for 2D effects, 3D materials, and post-processing.

Shader Types

shader_type canvas_item;    // 2D sprites, UI, CanvasItem nodes
shader_type spatial;        // 3D materials
shader_type particles;      // GPU particle systems
shader_type sky;            // Sky/environment
shader_type fog;            // Volumetric fog

Basic Shader Structure

shader_type canvas_item;

// Render modes (optional)
render_mode unshaded, blend_mix;

// Uniforms (exposed to inspector)
uniform vec4 tint_color : source_color = vec4(1.0);
uniform float intensity : hint_range(0.0, 1.0) = 0.5;
uniform sampler2D noise_texture : hint_default_white;

// Varyings (pass data vertex -> fragment)
varying vec2 world_position;

void vertex() {
    // Modify vertex position
    world_position = (MODEL_MATRIX * vec4(VERTEX, 0.0, 1.0)).xy;
}

void fragment() {
    // Output color
    vec4 tex_color = texture(TEXTURE, UV);
    COLOR = tex_color * tint_color;
}

Uniform Hints

// Color picker in inspector
uniform vec4 color : source_color = vec4(1.0);

// Slider with range
uniform float value : hint_range(0.0, 1.0, 0.01) = 0.5;

// Texture hints
uniform sampler2D albedo_tex : source_color, filter_linear_mipmap;
uniform sampler2D normal_tex : hint_normal;
uniform sampler2D noise_tex : hint_default_white;
uniform sampler2D mask_tex : hint_default_black;

// Instance uniforms (per-instance values)
instance uniform vec4 instance_color : source_color = vec4(1.0);

Built-in Variables

Canvas Item (2D)

// Vertex shader
VERTEX          // vec2 - vertex position
UV              // vec2 - texture coordinates
COLOR           // vec4 - vertex color
POINT_SIZE      // float - point size

// Fragment shader
UV              // vec2 - interpolated UVs
SCREEN_UV       // vec2 - screen space UVs
FRAGCOORD       // vec4 - fragment coordinates
COLOR           // vec4 - output color
NORMAL          // vec3 - normal for 2D lighting
TEXTURE         // sampler2D - sprite texture
TEXTURE_PIXEL_SIZE // vec2 - texel size

// Both
TIME            // float - shader time
PI              // float - 3.14159...
TAU             // float - 6.28318...