Tiny World Shader FX

Where the shaders live and how to extend them without breaking the guarded build.

Authoritative shader files

• Terrain: engine/landscape/shaders.js — SAND_VS, SAND_FS, LOWPOLY_FS
  • the sandMat / sandMatLowPoly ShaderMaterials.
• Water: engine/landscape/water.js — the animated reflective ocean plane.
• These two files Object.assign(LandscapeEngine.prototype, {...}) after LandscapeEngine.js defines the class, so they override the inline _initSharedShaders / _initWater copies still present in LandscapeEngine.js (lines ~302 / ~893). The split files are the live ones — edit those. The inline copies are dead but left in place; don't rely on them.
• The ocean time + cameraPos uniforms are advanced in LandscapeEngine.update().
• Voxel-world waterfalls/flow are separate: engine/world/05-tile-factory.js (getWaterfallCurtainMaterial, getWaterfallSurfaceMaterial, foam puffs) driven by updateWaterfallEffects(t) / tickWaterTextureFlow(dt) in the animation loop. check.js guards these names — keep them.

Ocean water shader (engine/landscape/water.js)

Stylized, cheap (~9 value-noise taps). Uniforms worth knowing:

• flowDir (vec2) — scroll direction; two layers flow along it and its perpendicular.
• foamColor / foamAmount — wave-crest + shoreline foam.
• specPower — Blinn-Phong sun-glint tightness.
• posterize — cel banding levels (12 reproduces the original look; 0 disables).
• planetDistance* — distance tint, kept in parity with the terrain materials.

Enhanced ocean water samples the shared planar reflection target from 01-render-core.js (tw-water-planar-reflection) via reflectionMatrix, then layers a localized refractive bend: refract(-viewDir, norm, 0.7502). Keep the runwayR discard, the clip-box block, fog, and posterize tail intact.

Enhanced water surfaces ("Enhanced water" toggle)

The default-visible water is voxel tiles (M.water/M.waterDk, Lambert), not the landscape ocean. A Settings toggle upgrades water everywhere:

• Setting: render-enhanced-water checkbox (HTML, Environment panel) ↔ renderEnhancedWater global (01-render-core.js, default on) ↔ tinyworld:render:enhancedWater. Wired in 21-object-transform-voxel-build.js (el ref, listener loop, applyFromControls, persistSettings, syncControls) exactly like the planesEnabled toggle. New key, no RENDER_SETTINGS_VERSION bump.
• Voxel water: injected in applyFlowingWaterUVs (04-textures.js) — the single onBeforeCompile chokepoint for every water material (base + flow clones). Stays Lambert; projects each water vertex into the shared planar reflection texture, then adds refractive bend, ripple-normal sheen, Blinn-Phong glint, and crest foam, masked by vTwWaterNrm.y so sides stay calm. The refractive sampler must use the derived world-flow UV (vTwWaterSurfaceUv / the same coordinates assigned to vMapUv), not raw mesh vUv. Shared waterShaderTimeUniform advanced in tickWaterTextureFlow. customProgramCacheKey is mandatory here — without it three.js would reuse the wrong program when the toggle flips (onBeforeCompile output isn't in the default cache key). Include the shader-variant string in both the program key and flow-material cache key when the injected shader source changes.
• Planar reflection capture: twWaterReflectionCapture() in 01-render-core.js renders the scene from a mirrored camera into tw-water-planar-reflection, hides reflective water meshes during the pass, and clips below-water geometry so underside slabs do not pollute the reflection. Water materials opt in with material.userData.twWaterReflective.
• Landscape ocean: uEnhance uniform in water.js scales foam/sheen/subsurface and the material samples the same planar reflection uniforms.
• On toggle: refreshWaterShaderMaterials() (clears waterFlowMaterialCache, resets the base materials) then rebuildTerrainRender(); the handler also sets the live landscape uEnhance. Waterfalls are untouched (separate shaders).
• The water albedo texture named ripples is intentionally neutral/no-stripe. Do not re-add baked horizontal/wavy line decals there; visible motion should come from the reflective/refractive shader and shoreline/waterfall edge foam.

TinyShaderFX library (engine/world/45-shader-fx.js)

IIFE exposing window.TinyShaderFX. 4-space body indent on purpose — the duplicate-declaration guard in tools/check.js only scans 2-space top-level decls, so anything deeper is ignored. Keep new locals inside the IIFE.

Factories (all procedural, no textures/render targets):

• makeWaterFlowMaterial(opts) — flowing river/pond surface for flat planes.
• makeWaterfallMaterial(opts) — vertical falling-water curtain (UV.y = top→bottom).
• makeFoamMaterial(opts) — shoreline/splash/wake foam ribbon (foam near UV.y=0).
• makeSmokeMaterial(opts) — dissolving smoke billboard; drive uAge 0→1.
• makeExplosionMaterial(opts) — fireball; drive uProgress 0→1 and scale the mesh.
• applyWear(material, opts) — patches any stock Lambert/Standard/Phong/Basic material with procedural grime/cracks/scuffs via onBeforeCompile (anchors on <project_vertex> and <dithering_fragment>, present in every stock template). Returns the material with a setWear(amount) helper.

Frame ticking

Animated materials expose uTime and self-register via track(). The loop calls window.__tinyworldShaderFXTick(t, dt) (wired in 25-animation-loop-schema.js, tick.effects bucket). Materials you build elsewhere advance for free if their uniform is named uTime and you pass them through TinyShaderFX.track().

Shared GLSL

TinyShaderFX.GLSL_NOISE is a prependable chunk of fxHash/fxNoise/fxFbm/ fxFresnel/fxPosterize (the fx-prefix avoids collisions with stock chunks). Reuse it for new ShaderMaterials instead of re-deriving noise.

Demo

?shaderfx=demo (or =1) drops a gallery near the origin; TinyShaderFX.demo(scene) does the same on demand. It's opt-in so default scenes are untouched.

Guard / gotchas

• New engine/** files are auto-collected by check.js (per-file new Function syntax check + cross-file duplicate-decl scan) and copied to dist/ by publish.sh — no extra wiring beyond the <script src> tag in the HTML.
• ShaderMaterial fragments need #include <colorspace_fragment> at the end to match the app's r185 output color space (the waterfall + FX materials all do this).
• When patching stock materials that sample material.map, write map UVs to r185's vMapUv (guarded by #ifdef USE_MAP), not the old generic vUv. vUv only exists when USE_UV is defined; map sampling uses <map_fragment> → vMapUv.
• Keep fragment shaders compatible with the app's WebGLRenderer path: use gl_FragColor, constant-bound for loops, and cameraPosition (auto-injected) in ShaderMaterial.
• Don't convert the existing chimney-smoke MeshBasicMaterial pipeline to a ShaderMaterial — it's cached/cloned by getCachedParticleMaterial. Use makeSmokeMaterial for new emitters instead.