shader-dev

name shader-dev description Comprehensive GLSL shader techniques for creating stunning visual effects — ray marching, SDF modeling, fluid simulation, particle systems, procedural generation, lighting, post-processing, and more. license MIT metadata {"version":"1.0","category":"graphics"} Shader Craft A unified skill covering 36 GLSL shader techniques (ShaderToy-compatible) for real-time visual effects. Invocation /shader-dev <request> $ARGUMENTS contains the user's request (e.g. "create a raymarched SDF scene with soft shadows"). Skill Structure shader-dev/ ├── SKILL.md # Core skill (this file) ├── techniques/ # Implementation guides (read per routing table) │ ├── ray-marching.md # Sphere tracing with SDF │ ├── sdf-3d.md # 3D signed distance functions │ ├── lighting-model.md # PBR, Phong, toon shading │ ├── procedural-noise.md # Perlin, Simplex, FBM │ └── ... # 34 more technique files └── reference/ # Detailed guides (read as needed) ├── ray-marching.md # Math derivations & advanced patterns ├── sdf-3d.md # Extended SDF theory ├── lighting-model.md # Lighting math deep-dive ├── procedural-noise.md # Noise function theory └── ... # 34 more reference files How to Use Read the Technique Routing Table below to identify which technique(s) match the user's request Read the relevant file(s) from techniques/ — each file contains core principles, implementation steps, and complete code templates If you need deeper understanding (math derivations, advanced patterns), follow the reference link at the bottom of each technique file to reference/ Apply the WebGL2 Adaptation Rules below when generating standalone HTML pages Technique Routing Table User wants to create... Primary technique Combine with 3D objects / scenes from math ray-marching + sdf-3d lighting-model, shadow-techniques Complex 3D shapes (booleans, blends) csg-boolean-operations sdf-3d, ray-marching Infinite repeating patterns in 3D domain-repetition sdf-3d, ray-marching Organic / warped shapes domain-warping procedural-noise Fluid / smoke / ink effects fluid-simulation multipass-buffer Particle effects (fire, sparks, snow) particle-system procedural-noise, color-palette Physically-based simulations simulation-physics multipass-buffer Game of Life / reaction-diffusion cellular-automata multipass-buffer, color-palette Ocean / water surface water-ocean atmospheric-scattering, lighting-model Terrain / landscape terrain-rendering atmospheric-scattering, procedural-noise Clouds / fog / volumetric fire volumetric-rendering procedural-noise, atmospheric-scattering Sky / sunset / atmosphere atmospheric-scattering volumetric-rendering Realistic lighting (PBR, Phong) lighting-model shadow-techniques, ambient-occlusion Shadows (soft / hard) shadow-techniques lighting-model Ambient occlusion ambient-occlusion lighting-model, normal-estimation Path tracing / global illumination path-tracing-gi analytic-ray-tracing, multipass-buffer Precise ray-geometry intersections analytic-ray-tracing lighting-model Voxel worlds (Minecraft-style) voxel-rendering lighting-model, shadow-techniques Noise / FBM textures procedural-noise domain-warping Tiled 2D patterns procedural-2d-pattern polar-uv-manipulation Voronoi / cell patterns voronoi-cellular-noise color-palette Fractals (Mandelbrot, Julia, 3D) fractal-rendering color-palette, polar-uv-manipulation Color grading / palettes color-palette — Bloom / tone mapping / glitch post-processing multipass-buffer Multi-pass ping-pong buffers multipass-buffer — Texture / sampling techniques texture-sampling — Camera / matrix transforms matrix-transform — Surface normals normal-estimation — Polar coords / kaleidoscope polar-uv-manipulation procedural-2d-pattern 2D shapes / UI from SDF sdf-2d color-palette Procedural audio / music sound-synthesis — SDF tricks / optimization sdf-tricks sdf-3d, ray-marching Anti-aliased rendering anti-aliasing sdf-2d, post-processing Depth of field / motion blur / lens effects camera-effects post-processing, multipass-buffer Advanced texture mapping / no-tile textures texture-mapping-advanced terrain-rendering, texture-sampling WebGL2 shader errors / debugging webgl-pitfalls — Technique Index Geometry & SDF sdf-2d — 2D signed distance functions for shapes, UI, anti-aliased rendering sdf-3d — 3D signed distance functions for real-time implicit surface modeling csg-boolean-operations — Constructive solid geometry: union, subtraction, intersection with smooth blending domain-repetition — Infinite space repetition, folding, and limited tiling domain-warping — Distort domains with noise for organic, flowing shapes sdf-tricks — SDF optimization, bounding volumes, binary search refinement, hollowing, layered edges, debug visualization Ray Casting & Lighting ray-marching — Sphere tracing with SDF for 3D scene rendering analytic-ray-tracing — Closed-form ray-primitive intersections (sphere, plane, box, torus) path-tracing-gi — Monte Carlo path tracing for photorealistic global illumination lighting-model — Phong, Blinn-Phong, PBR (Cook-Torrance), and toon shading shadow-techniques — Hard shadows, soft shadows (penumbra estimation), cascade shadows ambient-occlusion — SDF-based AO, screen-space AO approximation normal-estimation — Finite-difference normals, tetrahedron technique Simulation & Physics fluid-simulation — Navier-Stokes fluid solver with advection, diffusion, pressure projection simulation-physics — GPU-based physics: springs, cloth, N-body gravity, collision particle-system — Stateless and stateful particle systems (fire, rain, sparks, galaxies) cellular-automata — Game of Life, reaction-diffusion (Turing patterns), sand simulation Natural Phenomena water-ocean — Gerstner waves, FFT ocean, caustics, underwater fog terrain-rendering — Heightfield ray marching, FBM terrain, erosion atmospheric-scattering — Rayleigh/Mie scattering, god rays, SSS approximation volumetric-rendering — Volume ray marching for clouds, fog, fire, explosions Procedural Generation procedural-noise — Value noise, Perlin, Simplex, Worley, FBM, ridged noise procedural-2d-pattern — Brick, hexagon, truchet, Islamic geometric patterns voronoi-cellular-noise — Voronoi diagrams, Worley noise, cracked earth, crystal fractal-rendering — Mandelbrot, Julia sets, 3D fractals (Mandelbox, Mandelbulb) color-palette — Cosine palettes, HSL/HSV/Oklab, dynamic color mapping Post-Processing & Infrastructure post-processing — Bloom, tone mapping (ACES, Reinhard), vignette, chromatic aberration, glitch multipass-buffer — Ping-pong FBO setup, state persistence across frames texture-sampling — Bilinear, bicubic, mipmap, procedural texture lookup matrix-transform — Camera look-at, projection, rotation, orbit controls polar-uv-manipulation — Polar/log-polar coordinates, kaleidoscope, spiral mapping anti-aliasing — SSAA, SDF analytical AA, temporal anti-aliasing (TAA), FXAA post-process camera-effects — Depth of field (thin lens), motion blur, lens distortion, film grain, vignette texture-mapping-advanced — Biplanar mapping, texture repetition avoidance, ray differential filtering Audio sound-synthesis — Procedural audio in GLSL: oscillators, envelopes, filters, FM synthesis Debugging & Validation webgl-pitfalls — Common WebGL2/GLSL errors: fragCoord , main() wrapper, function order, macro limitations, uniform null WebGL2 Adaptation Rules All technique files use ShaderToy GLSL style. When generating standalone HTML pages, apply these adaptations: Shader Version & Output Use canvas.getContext("webgl2") Shader first line: #version 300 es , fragment shader adds precision highp float; Fragment shader must declare: out vec4 fragColor; Vertex shader: attribute → in , varying → out Fragment shader: varying → in , gl_FragColor → fragColor , texture2D() → texture() Fragment Coordinate Use gl_FragCoord.xy instead of fragCoord (WebGL2 does not have fragCoord built-in) // WRONG vec2 uv = (2.0 * fragCoord - iResolution.xy) / iResolution.y; // CORRECT vec2 uv = (2.0 * gl_FragCoord.xy - iResolution.xy) / iResolution.y; main() Wrapper for ShaderToy Templates ShaderToy uses void mainImage(out vec4 fragColor, in vec2 fragCoord) WebGL2 requires standard void main() entry point — always wrap mainImage: void mainImage(out vec4 fragColor, in vec2 fragCoord) { // shader code... fragColor = vec4(col, 1.0); } void main() { mainImage(fragColor, gl_FragCoord.xy); } Function Declaration Order GLSL requires functions to be declared before use — either declare before use or reorder: // WRONG — getAtmosphere() calls getSunDirection() before it's defined vec3 getAtmosphere(vec3 dir) { return getSunDirection(); } // Error! vec3 getSunDirection() { return normalize(vec3(1.0)); } // CORRECT — define callee first vec3 getSunDirection() { return normalize(vec3(1.0)); } vec3 getAtmosphere(vec3 dir) { return getSunDirection(); } // Works Macro Limitations #define cannot use function calls — use const instead: // WRONG #define SUN_DIR normalize(vec3(0.8, 0.4, -0.6)) // CORRECT const vec3 SUN_DIR = vec3(0.756, 0.378, -0.567); // Pre-computed normalized value Script Tag Extraction When extracting shader source from <script> tags, ensure #version is the first character — use .trim() : const fs = document . getElementById ( 'fs' ). text . trim (); Common Pitfalls Unused uniforms : Compiler may optimize away unused uniforms, causing gl.getUniformLocation() to return null — always use uniforms in a way the compiler cannot optimize out Loop indices : Use runtime constants in loops, not #define macros in some ES versions Terrain functions : Functions like terrainM(vec2) need XZ components — use terrainM(pos.xz + offset) not terrainM(pos + offset) HTML Page Setup When generating a standalone HTML page: Canvas fills the entire viewport, auto-resizes on window resize Page background black, no scrollbars: body { margin: 0; overflow: hidden; background: #000; } Implement ShaderToy-compatible uniforms: iTime , iResolution , iMouse , iFrame For multi-pass effects (Buffer A/B), use WebGL2 framebuffer + ping-pong (see multipass-buffer technique) Common Pitfalls JS Variable Declaration Order (TDZ — causes white screen crash) let / const variables must be declared at the top of the <script> block, before any function that references them: // 1. State variables FIRST let frameCount = 0 ; let startTime = Date . now (); // 2. Canvas/GL init, shader compile, FBO creation const canvas = document . getElementById ( 'canvas' ); const gl = canvas. getContext ( 'webgl2' ); // ... // 3. Functions and event bindings LAST function resize ( ) { /* can now safely reference frameCount */ } function render ( ) { /* ... */ } window . addEventListener ( 'resize' , resize); Reason: let / const have a Temporal Dead Zone — referencing them before declaration throws ReferenceError , causing a white screen. GLSL Compilation Errors (self-check after writing shaders) Function signature mismatch : Call must exactly match definition in parameter count and types. If defined as float fbm(vec3 p) , cannot call fbm(uv) with a vec2 Reserved words as variable names : Do not use: patch , cast , sample , filter , input , output , common , partition , active Strict type matching : vec3 x = 1.0 is illegal — use vec3 x = vec3(1.0) ; cannot use .z to access a vec2 No ternary on structs : ESSL does not allow ternary operator on struct types — use if / else instead Performance Budget Deployment environments may use headless software rendering with limited GPU power. Stay within these limits: Ray marching main loop: ≤ 128 steps Volume sampling / lighting inner loops: ≤ 32 steps FBM octaves: ≤ 6 layers Total nested loop iterations per pixel: ≤ 1000 (exceeding this freezes the browser) Quick Recipes Common effect combinations — complete rendering pipelines assembled from technique modules. Photorealistic SDF Scene Geometry : sdf-3d (extended primitives) + csg-boolean-operations (cubic/quartic smin)