shader-dev

What this skill does

# 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

1. Read the **Technique Routing Table** below to identify which technique(s) match the user's request
2. Read the relevant file(s) from `techniques/` — each file contains core principles, implementation steps, and complete code templates
3. If you need deeper understanding (math derivations, advanced patterns), follow the reference link at the bottom of each technique file to `reference/`
4. 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](techniques/ray-marching.md) + [sdf-3d](techniques/sdf-3d.md) | lighting-model, shadow-techniques |
| Complex 3D shapes (booleans, blends) | [csg-boolean-operations](techniques/csg-boolean-operations.md) | sdf-3d, ray-marching |
| Infinite repeating patterns in 3D | [domain-repetition](techniques/domain-repetition.md) | sdf-3d, ray-marching |
| Organic / warped shapes | [domain-warping](techniques/domain-warping.md) | procedural-noise |
| Fluid / smoke / ink effects | [fluid-simulation](techniques/fluid-simulation.md) | multipass-buffer |
| Particle effects (fire, sparks, snow) | [particle-system](techniques/particle-system.md) | procedural-noise, color-palette |
| Physically-based simulations | [simulation-physics](techniques/simulation-physics.md) | multipass-buffer |
| Game of Life / reaction-diffusion | [cellular-automata](techniques/cellular-automata.md) | multipass-buffer, color-palette |
| Ocean / water surface | [water-ocean](techniques/water-ocean.md) | atmospheric-scattering, lighting-model |
| Terrain / landscape | [terrain-rendering](techniques/terrain-rendering.md) | atmospheric-scattering, procedural-noise |
| Clouds / fog / volumetric fire | [volumetric-rendering](techniques/volumetric-rendering.md) | procedural-noise, atmospheric-scattering |
| Sky / sunset / atmosphere | [atmospheric-scattering](techniques/atmospheric-scattering.md) | volumetric-rendering |
| Realistic lighting (PBR, Phong) | [lighting-model](techniques/lighting-model.md) | shadow-techniques, ambient-occlusion |
| Shadows (soft / hard) | [shadow-techniques](techniques/shadow-techniques.md) | lighting-model |
| Ambient occlusion | [ambient-occlusion](techniques/ambient-occlusion.md) | lighting-model, normal-estimation |
| Path tracing / global illumination | [path-tracing-gi](techniques/path-tracing-gi.md) | analytic-ray-tracing, multipass-buffer |
| Precise ray-geometry intersections | [analytic-ray-tracing](techniques/analytic-ray-tracing.md) | lighting-model |
| Voxel worlds (Minecraft-style) | [voxel-rendering](techniques/voxel-rendering.md) | lighting-model, shadow-techniques |
| Noise / FBM textures | [procedural-noise](techniques/procedural-noise.md) | domain-warping |
| Tiled 2D patterns | [procedural-2d-pattern](techniques/procedural-2d-pattern.md) | polar-uv-manipulation |
| Voronoi / cell patterns | [voronoi-cellular-noise](techniques/voronoi-cellular-noise.md) | color-palette |
| Fractals (Mandelbrot, Julia, 3D) | [fractal-rendering](techniques/fractal-rendering.md) | color-palette, polar-uv-manipulation |
| Color grading / palettes | [color-palette](techniques/color-palette.md) | — |
| Bloom / tone mapping / glitch | [post-processing](techniques/post-processing.md) | multipass-buffer |
| Multi-pass ping-pong buffers | [multipass-buffer](techniques/multipass-buffer.md) | — |
| Texture / sampling techniques | [texture-sampling](techniques/texture-sampling.md) | — |
| Camera / matrix transforms | [matrix-transform](techniques/matrix-transform.md) | — |
| Surface normals | [normal-estimation](techniques/normal-estimation.md) | — |
| Polar coords / kaleidoscope | [polar-uv-manipulation](techniques/polar-uv-manipulation.md) | procedural-2d-pattern |
| 2D shapes / UI from SDF | [sdf-2d](techniques/sdf-2d.md) | color-palette |
| Procedural audio / music | [sound-synthesis](techniques/sound-synthesis.md) | — |
| SDF tricks / optimization | [sdf-tricks](techniques/sdf-tricks.md) | sdf-3d, ray-marching |
| Anti-aliased rendering | [anti-aliasing](techniques/anti-aliasing.md) | sdf-2d, post-processing |
| Depth of field / motion blur / lens effects | [camera-effects](techniques/camera-effects.md) | post-processing, multipass-buffer |
| Advanced texture mapping / no-tile textures | [texture-mapping-advanced](techniques/texture-mapping-advanced.md) | terrain-rendering, texture-sampling |
| WebGL2 shader errors / debugging | [webgl-pitfalls](techniques/webgl-pitfalls.md) | — |

## 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, M