godot-shaders

Godot Shaders (4.x)

Write canvas_item (2D) and spatial (3D) shaders in the Godot Shading Language, animate with TIME/UV, expose uniforms, and read the screen. Targets Godot 4.7.

When to use

• Use when writing .gdshader code or a ShaderMaterial: 2D effects (outline, dissolve, flash, water), 3D surface shaders (rim light, toon, scrolling UV), or screen-space post effects.

When not to use: the cross-engine concepts of shading (UVs, vertex/fragment theory) → shader-programming; particles/VFX nodes → general 3D; non-shader visuals.

Core workflow

1. Pick the shader type on the first line: shader_type canvas_item; for 2D (Sprite2D, TextureRect, anything CanvasItem) or shader_type spatial; for 3D materials. (particles, sky, fog also exist.)
2. Attach via a ShaderMaterial. Create a ShaderMaterial, assign your .gdshader, and put it on the node's material. Uniforms appear in the Inspector.
3. Write fragment() to set the output: COLOR (2D) or ALBEDO/EMISSION/ALPHA (3D). Optionally vertex() to move geometry and light() for custom lighting.
4. Expose tunables as uniforms with hints (source_color, hint_range) so they are editable and correctly color-managed.
5. Animate with the built-in TIME and sample textures with texture(tex, UV).
6. Set uniforms from code with material.set_shader_parameter("name", value).

Patterns

1. 2D (canvas_item): tint + scrolling UV

shader_type canvas_item;

uniform vec4 tint : source_color = vec4(1.0);     // source_color = sRGB-correct color
uniform float scroll_speed : hint_range(0.0, 2.0) = 0.3;

void fragment() {
    vec2 uv = UV;
    uv.x += TIME * scroll_speed;                  // scroll horizontally over time
    COLOR = texture(TEXTURE, uv) * tint;          // TEXTURE = the node's texture
}

2. 2D dissolve using a noise threshold

shader_type canvas_item;

uniform sampler2D noise : repeat_enable;          // a NoiseTexture2D
uniform float amount : hint_range(0.0, 1.0) = 0.0;

void fragment() {
    vec4 tex = texture(TEXTURE, UV);
    float n = texture(noise, UV).r;
    if (n < amount) {
        discard;                                  // cut the pixel away
    }
    COLOR = tex;
}