godot-shaders-basics

Shader Basics Fragment/vertex shaders, uniforms, and built-in variables define custom visual effects. Available Scripts vfx_port_shader.gdshader Expert shader template with parameter validation and common effect patterns. shader_parameter_animator.gd Runtime shader uniform animation without AnimationPlayer - for dynamic effects. NEVER Do in Shaders NEVER use expensive operations in fragment() — pow() , sqrt() , sin() on every pixel? 1920x1080 = 2M calls/frame = lag. Pre-calculate OR use texture lookups. NEVER forget to normalize vectors — reflect(direction, normal) without normalization? Wrong reflections + rendering artifacts. ALWAYS normalize direction vectors. NEVER use if/else for branching — GPUs hate branching (SIMD architecture). Use mix() , step() , smoothstep() for conditional logic. NEVER modify UV without bounds check — UV.x += 10.0 goes outside 0-1 range? Texture sampling breaks. Use fract() OR clamp() . NEVER use TIME without delta — COLOR.a = sin(TIME) runs at variable speed on different framerates. Use TIME * speed_factor for consistent animation. NEVER forget hint_source_color for colors — uniform vec4 tint without hint? Inspector shows raw floats. Use uniform vec4 tint : source_color for color picker. shader_type canvas_item; void fragment() { // Get texture color vec4 tex_color = texture(TEXTURE, UV); // Tint red COLOR = tex_color * vec4(1.0, 0.5, 0.5, 1.0); } Apply to Sprite: Select Sprite2D node Material → New ShaderMaterial Shader → New Shader Paste code Common 2D Effects Dissolve Effect shader_type canvas_item ; uniform float dissolve_amount : hint_range ( 0.0 , 1.0 ) = 0.0 ; uniform sampler2D noise_texture ; void fragment ( ) { vec4 tex_color = texture ( TEXTURE , UV ) ; float noise = texture ( noise_texture , UV ) . r ; if ( noise < dissolve_amount ) { discard ; // Make pixel transparent } COLOR = tex_color ; } Wave Distortion shader_type canvas_item ; uniform float wave_speed = 2.0 ; uniform float wave_amount = 0.05 ; void fragment ( ) { vec2 uv = UV ; uv . x += sin ( uv . y * 10.0 + TIME * wave_speed ) * wave_amount ; COLOR = texture ( TEXTURE , uv ) ; } Outline shader_type canvas_item ; uniform vec4 outline_color : source_color = vec4 ( 0.0 , 0.0 , 0.0 , 1.0 ) ; uniform float outline_width = 2.0 ; void fragment ( ) { vec4 col = texture ( TEXTURE , UV ) ; vec2 pixel_size = TEXTURE_PIXEL_SIZE * outline_width ; float alpha = col . a ; alpha = max ( alpha , texture ( TEXTURE , UV + vec2 ( pixel_size . x , 0.0 ) ) . a ) ; alpha = max ( alpha , texture ( TEXTURE , UV + vec2 ( - pixel_size . x , 0.0 ) ) . a ) ; alpha = max ( alpha , texture ( TEXTURE , UV + vec2 ( 0.0 , pixel_size . y ) ) . a ) ; alpha = max ( alpha , texture ( TEXTURE , UV + vec2 ( 0.0 , - pixel_size . y ) ) . a ) ; COLOR = mix ( outline_color , col , col . a ) ; COLOR . a = alpha ; } 3D Shaders Basic 3D Shader shader_type spatial ; void fragment ( ) { ALBEDO = vec3 ( 1.0 , 0.0 , 0.0 ) ; // Red material } Toon Shading (Cel-Shading) shader_type spatial ; uniform vec3 base_color : source_color = vec3 ( 1.0 ) ; uniform int color_steps = 3 ; void light ( ) { float NdotL = dot ( NORMAL , LIGHT ) ; float stepped = floor ( NdotL * float ( color_steps ) ) / float ( color_steps ) ; DIFFUSE_LIGHT = base_color * stepped ; } Screen-Space Effects Vignette shader_type canvas_item ; uniform float vignette_strength = 0.5 ; void fragment ( ) { vec4 color = texture ( TEXTURE , UV ) ; // Distance from center vec2 center = vec2 ( 0.5 , 0.5 ) ; float dist = distance ( UV , center ) ; float vignette = 1.0 - dist * vignette_strength ; COLOR = color * vignette ; } Uniforms (Parameters) // Float slider uniform float intensity : hint_range ( 0.0 , 1.0 ) = 0.5 ; // Color picker uniform vec4 tint_color : source_color = vec4 ( 1.0 ) ; // Texture uniform sampler2D noise_texture ; // Access in code: material . set_shader_parameter ( "intensity" , 0.8 ) Built-in Variables 2D (canvas_item): UV - Texture coordinates (0-1) COLOR - Output color TEXTURE - Current texture TIME - Time since start SCREEN_UV - Screen coordinates 3D (spatial): ALBEDO - Base color NORMAL - Surface normal ROUGHNESS - Surface roughness METALLIC - Metallic value Best Practices 1. Use Uniforms for Tweaking // ✅ Good - adjustable uniform float speed = 1.0 ; void fragment ( ) { COLOR . r = sin ( TIME * speed ) ; } // ❌ Bad - hardcoded void fragment ( ) { COLOR . r = sin ( TIME * 2.5 ) ; } 2. Optimize Performance // Avoid expensive operations in fragment shader // Pre-calculate values when possible // Use textures for complex patterns 3. Comment Shaders // Water wave effect // Creates horizontal distortion based on sine wave uniform float wave_amplitude = 0.02 ; Reference Godot Docs: Shading Language Godot Docs: Your First Shader Related Master Skill: godot-master