Synchrony Demo Creation and Index Update

The task says "Wake up and do as you please." Based on my purpose, I should create cool Three.js demos. The last execution created demo 025 (Ferrofluid). So the natural next step is to create demo 026 — a new advanced Three.js demo — and update the index page.

Let me first install shell tools and look at the current state of the demos folder.

Let me check the current state of the demos folder to see what demos exist and what the index looks like.

The task is "Wake up and do as you please." — following the established pattern, I should create demo 026. Let me look at a recent demo to understand the style/structure used, then create a new advanced demo.

Let me check the most recent demo (025-ferrofluid) briefly to see the structure, and also see the index format for demo cards.

The task is "Wake up and do as you please." Following the established daily pattern, I should create demo 026 — a new advanced Three.js demo — and update the index.

Let me think about what to build. Previous demos:

1. Spinning cube
2. Nebula galaxy (particles)
3. Mandelbulb explorer (ray marching fractal)
4. Fluid dynamics
5. Gravity sandbox
6. Event horizon (black hole)
7. Sonic reactor (audio)
8. Void runner (game)
9. Azure odyssey (flight?)
10. Abyssal bloom (deep sea boids)
11. Physarum garden (slime mold)
12. Powder alchemy (falling sand)
13. Clockwork nebula (orrery gears)
14. Neon rain (cyberpunk city)
15. Aurora borealis
16. Skitter (creature locomotion)
17. Coral resonance (cymatics)
18. Threshold (portals)
19. Attractorium (strange attractors)
20. Murmuration (boids flocking)
21. Terraforge (erosion terrain)
22. Cloudsea (volumetric clouds)
23. Frostline (frost crystal sim)
24. Koi pond (water sim)
25. Ferrofluid (magnetic liquid)

What's missing? Ideas for 026:

• Fire / combustion simulation — GPU fluid fire with smoke
• Cloth / soft body physics — a cloth playground
• Lightning / plasma — Tesla coil, electric arcs
• Crystal growth / DLA — diffusion-limited aggregation
• Ocean waves — Gerstner/FFT ocean (koi pond was a pond, but a full FFT ocean with buoyancy could be different)
• Kaleidoscope / mandala shader
• Voxel builder / minecraft-like
• Snake 3D game
• Rube Goldberg / marble run physics
• Spider web / silk physics — procedural web building
• Ink in water — smoke/dye simulation (but fluid dynamics was done at 004)
• Sand pendulum / harmonograph
• Solar system / orbital mechanics game (gravity sandbox at 005 covers some)
• Wormhole / hyperspace tunnel
• Tornado / storm chaser — volumetric tornado with debris
• Lava lamp / metaballs — ray-marched metaballs with physics
• Electric circuit / logic gates
• Mycelium / fungal network
• Bioluminescent cave (covered partially by 018)
• Pendulum waves / double pendulum chaos
• Turing patterns / reaction-diffusion — Gray-Scott! That hasn't been done explicitly. Physarum is agent-based; Gray-Scott reaction-diffusion is different — spots, stripes, coral growth patterns. Could be a 3D extrusion or a beautiful 2D plane with interactive feeding.
• Fireflies / synchronization — coupled oscillators (Kuramoto model) — fireflies synchronizing! That's a beautiful concept: thousands of fireflies in a night forest, each an oscillator, they synchronize their flashing via the Kuramoto model. Interactive: click to flash, disturb, etc.
• Origami / paper folding
• Kinetic sculpture / wave field — a field of pins/rods moving in waves (like those kinetic art installations)
• Tesla / plasma globe — interactive plasma globe with lightning filaments following your pointer! That's visually striking and fun. Ray-marched or line-based arcs with glow.
• Ant colony / termite
• Deep sea anglerfish
• Space elevator
• Dyson swarm — building a Dyson swarm around a star, satellite by satellite. That's cool: a star with accretion, you launch satellites that form a swarm, energy counter grows. Game-like.
• Tornado of fire
• Glass caustics / prism dispersion — light dispersion through prisms, rainbow caustics. Beautiful optics demo.
• Spider web with dew — morning dew on a web, physics-based strands, light refraction in droplets.

Let me pick something with strong "wow" factor that is distinct: Plasma Storm / Tesla globe? Or Gray-Scott reaction-diffusion 3D? Or Kuramoto firefly synchronization?

The firefly synchronization idea is beautiful and has a real scientific model (Kuramoto coupled oscillators), it's interactive (your light disturbs/entrains them), and hasn't been done. Night forest / mangrove setting with water reflections, thousands of fireflies with bloom, generative audio. It fits the collection's style (nature + science + interaction + audio + post FX).

Actually, let me think about what would be most impressive and technically interesting:

"Firefly Sync" / "Synchrony" — A moonlit mangrove/meadow at night with up to ~2-4k fireflies, each a phase oscillator. Kuramoto coupling: fireflies within a radius (or seeing flashes) adjust their phase toward neighbors. Global synchrony emerges. Features:

• GPU instanced fireflies with shader-based flash envelopes (sharp attack, exponential decay)
• Kuramoto model on CPU (O(n²) too heavy for 3k... 3k² = 9M ops per frame — too heavy on CPU per frame, but could do spatial hashing, or do coupling only with K nearest / random subset). Alternatively GPGPU: positions in textures, phases in textures, O(n²) in fragment shader like Murmuration did (9,216 birds O(n²) in fragment shaders). So GPGPU Kuramoto is feasible: phase texture, each firefly reads all others' phases... but coupling in Kuramoto doesn't need positions — it's mean-field or nearest-neighbor. Mean-field Kuramoto: dθᵢ/dt = ωᵢ + (K/N) Σ sin(θⱼ - θᵢ). That's a global sum — perfect for GPU reduction or even CPU with 4k fireflies (4k ops per frame is trivial!). Mean-field coupling is O(n) per frame — super cheap.

But pure mean-field is less interesting visually (whole swarm syncs uniformly). Better: spatial coupling — fireflies couple to neighbors within a radius, producing traveling sync waves. With spatial hashing on CPU, 2-3k fireflies each checking ~10-30 neighbors = ~50-90k ops/frame — fine on CPU.

Actually a well-known model: fireflies respond to flashes (pulse-coupled oscillators, Mirollo-Strogatz / Peskin model): when a firefly sees a flash, its phase jumps forward. That's event-driven and produces realistic sync waves. Implement: each firefly has phase; when phase crosses 1, it flashes (emits light for ~0.5s). Other fireflies within sight radius get a phase kick ε. This is cheap with spatial hashing.

Visuals:

• Night meadow/mangrove with water plane reflecting firefly flashes (planar reflection or simple mirrored rendering)
• Instanced grass/reeds swaying
• Trees silhouettes
• Moon, stars, mist
• Fireflies as instanced sprites with glow; flash light affects nearby grass (fake: vertex shader lightening near flashes — could pass N brightest firefly positions as uniforms)
• Bloom post-processing essential
• Generative audio: night crickets that also synchronize? Maybe subtle pads + cricket chirps tied to flash events.

Interactions:

• Move pointer: a "lantern" that attracts fireflies and entrains them (your light pulses)
• Click: emit a flash pulse that kicks phases locally (sync wave emanates)
• Slider: coupling strength K (0 = chaos, high = perfect unison), flash frequency, density
• Presets: "Chaos" (K=0), "Synchronicity" (high K), "Wave" (spatial coupling only), "Heartbeat"
• Order parameter R display (Kuramoto order parameter) — a live "synchrony meter"! That's a great HUD element: shows the degree of synchronization 0-100%.
• Camera: orbit / drift modes
• Adaptive quality, snapshots, touch support

This is distinct from Murmuration (boids spatial movement) — here the science is temporal synchronization, fireflies drift gently but the star is the phase dynamics. The synchrony meter and sync waves are unique.

Name: "Synchrony — Firefly Observatory" or "Firefly Sync". Folder: 026-firefly-sync or 026-synchrony. I'll go with "026-synchrony" and title "Synchrony".

Let me design the demo in detail:

Scene:

• Night wetland: dark blue-green palette, moon low on horizon, stars
• Water plane (mirror reflections — use simple planar reflection via Reflector? Three.js has Reflector addon. With bloom it's gorgeous. Reflector renders scene again — expensive but ok. Alternatively fake reflection: render fireflies mirrored below water plane with fade. Cheaper: a second instanced mesh mirrored with transparency. I'll do a real planar Reflector for the water with low res, or fake. Let me use THREE.Reflector from addons with a blur/dark tint... Reflector is sharp mirror; water needs ripple distortion. I can write a custom water shader that samples the reflection texture with animated distortion. That's what Koi Pond did (live-rendered refraction). To keep it fresh, maybe do fake mirrored fireflies + distortion shader. Hmm, but real reflections of moon + trees are nice.

Simpler robust approach: custom WaterMirror: render scene to target with mirrored camera (like Reflector), then water shader samples with normal-perturbed UV distortion + fresnel + dark tint. I'll implement a compact version of Reflector logic myself (it's ~50 lines) to have control. Actually the Reflector addon allows passing a custom shader? THREE.Reflector accepts shader option to customize. Yes! Reflector supports custom shader with tDiffuse and textureMatrix uniforms. I can pass a shader that adds ripple distortion, fresnel fade, and tint.

• Grass: instanced blades (crossed quads or single blade geometry) swaying in vertex shader, ~30-60k instances. Firefly light: pass up to ~24 brightest firefly positions+intensity as uniform arrays; grass fragment shader accumulates warm glow. Also reeds/cattails silhouettes.
• Trees: a few dark silhouette trees (cones/billboards) at the back, plus mangrove-like roots? Keep simple: layered billboard silhouettes with slight parallax.
• Mist: a few large soft sprites drifting low over water.
• Moon: bright disc with halo (sprite), stars: points with twinkle.
• Fireflies: THREE.InstancedMesh of small quad (billboarded in shader) or Points with custom shader. Points with size attenuation is easiest and fast for 3k. But nice firefly = core + halo. Points with a radial-gradient sprite texture generated procedurally, additive blending, works great with bloom. Flash envelope computed in shader from per-instance attributes (phase, frequency, flashTime) — actually phase integration happens on CPU each frame (cheap), we write instance attributes: position (drift), intensity. Use InstancedBufferGeometry with a quad for better control (core+halo in fragment). I'll use instanced quads billboarded in vertex shader.

Simulation (CPU, per frame):

• N fireflies (default 2200, quality tiers 900/1600/2200/3000)
• State: phase φ ∈ [0,1), intrinsic period T (0.9–1.3s), position, velocity (gentle wander + attraction to lantern), flash intensity
• Update: φ += dt/T. When φ wraps → flash event: intensity=1, decays exp(-t*~6). Record flash events this frame.
• Pulse coupling: for each flash event, neighbors within radius R (spatial hash grid) get phase kick: Δφ = ε * (something) — Mirollo-Strogatz: phase advances by ε*(1-φ)? Classic PRC (phase response curve): advance more if mid-cycle. Use Δφ = ε * sin? Simple: φ += ε * (1 - φ) * strength (advance toward flashing). Also slight refractory: if firefly just flashed (φ small), ignore.
• Spatial hash: cell size = R, rebuild each frame (N small, fine).
• Also visual-only coupling option "mean-field" vs "local". Keep local.
• Order parameter: R_order = |mean(e^{i2πφ})| computed each frame — drives the sync meter + audio.
• Wander: perlin-ish flow field (cheap sin/cos combos), soft bounds elliptical region over the meadow, avoid lantern? attracted mildly.
• Lantern (pointer): raycast to meadow plane, lantern light position; fireflies within radius get phase entrained toward lantern's own pulse (lantern pulses at fixed interval when active) — simpler: clicking emits a pulse that kicks phases of nearby fireflies (sync wave). Pointer held = lantern light that attracts fireflies.

Audio (WebAudio, generative):

• Night ambience: filtered noise (wind), cricket chirps (high-freq pulses with vibrato) that subtly cluster with the global flash rhythm when synchronized
• Soft pad chords
• When a big synchronized wave passes near the camera/center, a soft "shimmer" (celesta-ish pentatonic notes) — tie chime probability to local flash density near center.
• Mute button + starts on first interaction (autoplay policy).

Post: UnrealBloomPass + custom grade pass (vignette, grain, slight teal shadows) via ShaderPass.

UI: panel with title, stats (fps, fireflies, sync %), sliders: Coupling ε, Flash rate, Glow/bloom, Density? (rebuild), buttons: presets (Chaos / Meadow / Unison / Pulse Wave), Pulse (emit sync pulse), Pause, Snapshot, Audio, Quality auto. Hint bar. Sync meter: a circular or bar gauge showing order parameter with label "synchrony".

Keyboard: Space pulse, P pause, H hide UI, 1-4 presets, M mute, S snapshot.

Adaptive quality: measure fps, adjust firefly count / grass count / bloom resolution.

This is a solid plan. Now write the code. Single self-contained index.html with import map to three@0.160+ (use 0.164.1 or similar from unpkg; previous demos presumably use a version — let me check what 025 used for consistency).

Let me check the import map of ferrofluid quickly, and also check how big the file is (41K). I'll write mine similarly structured.

Let me look at a bit more of the ferrofluid file to match conventions (import map, addons used).

Good — three@0.170.0 with import maps, EffectComposer + UnrealBloom. I'll build demo 026: "Synchrony" — a firefly synchronization observatory using pulse-coupled oscillators (Mirollo–Strogatz / Kuramoto-style) in a moonlit wetland with planar-reflection water, instanced swaying grass lit by nearby flashes, mist, generative WebAudio, bloom + grade pass, sync meter, presets, adaptive quality, snapshots, touch support.

Let me now write the full demo. I'll be careful with:

• GLSL syntax (no smoothstep mistakes, balanced braces)
• JS syntax (will validate with node --check after extracting module script)
• Performance: spatial hash for coupling, instanced everything

Architecture:

uniform mat4 textureMatrix; varying vec4 vUv; void main() { vUv = textureMatrix * vec4( position, 1.0 ); gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 ); }

vUv = textureMatrix * vec4( position, 1.0 ); gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

const shader = options.shader || Reflector.ReflectorShader; ... this.material = new ShaderMaterial({ name: shader.name, uniforms: UniformsUtils.clone( shader.uniforms ), fragmentShader: shader.fragmentShader, vertexShader: shader.vertexShader }); this.material.uniforms.tDiffuse.value = renderTarget.texture; this.material.uniforms.textureMatrix.value = textureMatrix;

vec3 right = vec3(viewMatrix[0][0], viewMatrix[1][0], viewMatrix[2][0]); vec3 up = vec3(viewMatrix[0][1], viewMatrix[1][1], viewMatrix[2][1]); float size = uSize * (0.55 + aFlash1.9); vec3 wp = aOffset + (rightposition.x + up*position.y) * size;

float d = length(vUv-0.5)2.0; float core = smoothstep(0.25,0.05,d); float halo = exp(-dd*3.5)*0.6; float a = (core + halo) * vFlash; vec3 col = mix(vec3(1.0,0.75,0.35), vec3(0.65,1.0,0.45), vSeed) ...

for i<active: f.phase += dt/(f.periodtempoScale) if f.phase>=1: f.phase-=1; flash(i) f.flashT += dt; intensity = envelope wander: ang = noise-ish: sin(f.seed12.9 + t0.3)... use flow: a = sin(x0.08+t0.12)+cos(z0.07 - t0.09) ... vx += cos(a)accdt ... plus center pull: d=length(xz); if d>30 pull in lantern attraction if within 10 speed clamp 0.8; pos += vdt; y bob: y += sin(t0.7+seed*7)0.15dt... keep y in [0.5,5.5] soft

rebuild hash each frame: cell=radius (current coupling radius) for each flash event this frame: neighbors in 3x3 cells: if ni!=i && phase>0.12 && flashT>0.3: phase += eps*(1-phase)*kickScale; if phase>=1 {phase-=1; flash(ni)} // immediate cascade allowed? Mirollo-Strogatz allows cascade; allow but guard infinite loop: process flashes queue FIFO with per-firefly once-per-frame flag.

vec3 d = normalize(vDir); // grid on direction: use 3D hash cells vec3 p = d*140.0; vec3 ip = floor(p); vec3 fp = fract(p); float h = hash(ip); star if h>0.997: brightness by hash, point = smoothstep(0.08,0.0,length(fp-0.5)) ...

col = texture(tDiffuse, vUv); // chromatic aberration at edges vec2 d = vUv-0.5; float r2=dot(d,d); col.r = texture(tDiffuse, vUv + dr20.012).r; (sample before base? do CA first: sample 3 taps) // teal shadows / warm highlights col = pow(col, vec3(1.02,1.0,0.98)); col += (vec3(0.02,0.05,0.07) * (1.0-smoothstep(0.0,0.35,luma))) * 0.6; // vignette col *= 1.0 - smoothstep(0.35,0.95,sqrt(r2))0.55; // grain col += (hash(vUvres+t)-0.5)*0.035;

It only touches tDiffuse & textureMatrix. color is set from options.color into uniforms if exists? In r170:

Hmm not sure. I'll include color uniform anyway (harmless).

onBeforeRender: updates textureMatrix from camera, sets material.visible false during its own render... standard.

Multisample option: r170 Reflector supports multisample option. Set 4 on high? Keep default 4? Default is 4. Fine.

Edge: Reflector renders scene WITHOUT tone mapping? It renders to RT with renderer settings; materials' output linear; then composited. Fine.

Water fragment plan:

Note: Reflector clips below-plane geometry via oblique projection — grass under water? none. OK.

Also: Reflector + instanced grass double-render cost fine.

One more consideration: the water plane is huge (420) and the ground disc radius 48 sits at y=0.02 above it. Reflection of ground disc edge → fine.

Trees: MeshBasicMaterial with map + transparent + depthWrite true? Alpha-tested (alphaTest 0.5) to avoid sort issues with water reflection. Use alphaTest 0.35, side DoubleSide.

Mist: MeshBasicMaterial additive? Normal blending with opacity per-instance? Use single InstancedMesh with per-instance random via gl_InstanceID? Simpler: 10 individual Mesh clones sharing material with onBeforeCompile? Overkill — use ShaderMaterial instanced with aSeed attribute, billboard=false (flat). I'll do InstancedBufferGeometry quad rotated flat, shader: alpha = soft radial * fbm streaks * (0.5+0.5sin(tspeed+seed)). Blending: NormalBlending, transparent, depthWrite false. Color pale #6f87a8, alpha max 0.10.

Fireflies count uniform uSize: world size of quad ~0.5 base.

Now the JS structure:

Preset application sets sliders + variables.

Snapshot:

Alright — also the "Tide" preset: tideTimer in animate: every 7s: pulseAt(edgePoint alternating) with big radius 16, kick 0.5, ring visual, soft chime.

pulseAt(point, radius, kick): for fireflies within radius (use hash or brute force — brute 3000 fine on click): phase += kick*(1-phase) with falloff (1-d/radius)*kick; allow cascade via queue next frames naturally (they'll flash when wrapping). Add ring mesh animation, chime, lantern-independent.

Ring pool: 8 meshes RingGeometry(0.95,1,64) flat; material ShaderMaterial additive: uniform uT (0..1): alpha = smoothstep... scale = 0.5 + t*radius. In animate update active rings.

Lantern: sprite (canvas radial texture), position lerp to target (y=1.5), pulse timer 1.15s when pointerActive (last move < 4s ago): small pulseAt(lantern, 8, 0.35+eps) + tiny ring + very soft tick sound? skip sound.

Attraction: fireflies within 9 of lantern: accel toward lantern point 0.6, plus orbit tangential 0.3 for swirl.

Now — audio code:

Pulse sound: thump + shimmer(2 notes).

Visibility: on hidden → ctx.suspend? just mute master; on visible restore.

Fine. Time to write. I'll aim for clean, commented code.

Also stats & meter DOM:

Meter: bar 100% width, gradient fill green→cyan, glow when high.

Sliders: coupling(0..0.4 step .01), radius(3..10 step .5), tempo(0.6..1.6 step .05), glow(0..1.6 step .05 → bloom strength), density(400..3000 step 100).

Buttons row1 (presets): Chaos Meadow Unison Tide; row2: Pulse, Drift, Sound, Snap, Hide.

Keyboard as planned.

Title: "SYNCHRONY", sub: "pulse-coupled firefly observatory".

Hint: "move — lantern · click — sync pulse · drag — orbit · scroll — zoom · space — pulse · h — hide ui"

Colors: panel accent greens/cyans: gradient #a3e635 → #34d399? Firefly palette: lime/gold. Panel border rgba(163,230,53,0.18).

Let me write the file now. I'll write it fully, then validate.

One more check — InstancedBufferGeometry + RawShaderMaterial? Use ShaderMaterial (has built-ins). For instanced attributes: geometry.setAttribute('aOffset', new THREE.InstancedBufferAttribute(arr,3).setUsage(DynamicDrawUsage)).

For grass: same technique; static attributes.

instanceCount: geometry.instanceCount = n (for InstancedBufferGeometry default is Infinity → uses attribute count; setting explicitly works; in newer three, geometry.instanceCount).

Frustum culling: instanced meshes need mesh.frustumCulled=false (or proper bounding sphere). Set frustumCulled=false on grass, fireflies, mist.

Reflector renders scene → fireflies frustumCulled false fine.

Let me also ensure fireflies don't go below water reflection weirdness — y min 0.5.

Write now.

Actually, let me reconsider the grass light loop cost: 60k instances * 10 verts? No — per-fragment loop 24 lights * grass pixels. Grass covers maybe 40% of screen; 24 iterations of simple math per fragment — fine on GPU. Ground plane covers big area too — same loop, fine.

Vertex vs fragment for lights: compute in vertex (10 verts/blade) and interpolate — cheaper and looks fine at blade scale? Light pools vary over meters; blade height ~1m — vertex lighting acceptable and much cheaper. I'll compute light accumulation in vertex, pass as vGlow vec3. Ground: compute in fragment (plane has few verts — must be fragment). Ground pixels many but loop cheap. OK: grass vertex, ground fragment.

Water: mirror handles firefly reflections; add lantern pool? skip.

Let me write everything now. Also remember: DO NOT use smoothstep(edge0>edge1) incorrectly — GLSL smoothstep requires edge0<edge1 (results undefined otherwise). For inverted use 1.0-smoothstep(a,b,x).

Hash functions:

Sky stars 3D hash:

Stars:

Branchy but fine. Better: compute without if: star = step(0.992,h)*... Use smooth. ok.

Moon crater: fbm on projected coords: vec2 mp = vec2(dot(d,mu), dot(d,mv)) / discScale; crat = fbm2(mp*8.0)*0.3; moonCol = (1.0-cratsmoothstep...).

Alright, writing the file. Given length (~1100+ lines), write in one go carefully.

Let me draft the JS sim constants:

• MAXF = 3000
• meadow R = 33 (xz ellipse), y in [0.6, 5.2]
• periods: 0.85..1.25 / tempoScale

Envelope: flashT since flash; I = flashT<0.07 ? flashT/0.07 : Math.exp(-(flashT-0.07)*4.5); if flashT>1.2 → 0.

Cascade queue: Int32Array(MAXF), head/tail; flashedFlag Uint8Array.

Hash: cell size = couplingRadius (rebuild when changes). Map<int, int[]> — allocate arrays each frame = GC churn; use simpler: since N small, brute-force O(n²) for coupling only on flash events? Worst case unison: 3000 flashes in same frame each scanning 3000 = 9M — too heavy. Spatial hash needed. Implement with typed arrays: counting sort style:

Simpler: Map<key, number[]> reused: keep arrays pooled. Honestly N=3000: Map with arrays per frame is ~ fine (3000 pushes into ~hundreds of arrays). GC ok. I'll do Map with integer key (gx + gz*4096), values arrays cached in a pool: keep grid = new Map() persistent; each frame: for (arr of grid.values()) arr.length=0; then fill.

Neighbor search: for cell (gx-1..gx+1, gz-1..gz+1) lookup.

Flash processing: queue = flashes this frame (from natural wraps). Process queue with cascade: pop i, find neighbors, kick; if neighbor wraps → push. Use index-based queue array with head pointer; flags prevent re-kick loops: a firefly can be kicked multiple times per frame by different flashes (that's fine, real), but only flash once per frame (flag).

Order param & top lights in same loop.

Positions update: simple Euler.

Also fireflies should avoid camera? no need.

Density change: activeCount = value; geometry.instanceCount = activeCount (fireflies). Sim loops to activeCount. Dead ones intensity 0.

Adaptive tiers:

Start at 1. fpsEMA; every 2.5s: if ema<42 && tier<3 tier++ apply; else if ema>56 && tier>0: stableCount++; if stableCount>=4 tier-- apply. apply(): renderer.setPixelRatio(pr); onResize(); grass.geometry.instanceCount; fireActive = min(userDensity, tier.flies) — but user density slider should override... effective = min(user, tierFlies). Show in stats.

Bloom strength from glow slider (default 0.9). Grade pass always.

OK writing now. Also include a subtle shooting star? skip — enough features.

Let me write the HTML file.

Now the full code. I'll write it section by section in the file.

Careful with template literals inside shaders — I'll use plain string concatenation or template literals; template literals fine in module. No nested backticks issues.

One risk: In GLSL, texture2D vs texture — three injects #define texture2D texture for GLSL3? ShaderMaterial default GLSL1 → texture2D fine.

cameraPosition available in vertex & fragment of ShaderMaterial (three provides it in vertex always; in fragment, uniform vec3 cameraPosition is also injected — yes, three adds cameraPosition to fragment shader prefix for ShaderMaterial).

viewMatrix available in vertex (built-in). In fragment not — pass what I need via varyings.

Grass vertex uses cameraPosition for fog distance — available in vertex. ok.

Let me now also design tree canvas texture:

Trees as planes DoubleSide alphaTest 0.4. 6 trees positions fixed ring.

Mist texture: canvas 256: radial gradient + noise blobs.

Lantern sprite texture: radial gradient warm.

Now writing the actual file content. I'll produce it in the write call. Then validate.

For the index card description:

"026 — Synchrony — A pulse-coupled firefly observatory ..." mention: Mirollo–Strogatz pulse coupling + Kuramoto order parameter, up to 3,000 fireflies over a moonlit mirror-water wetland, 60k instanced grass blades lit by the 24 brightest flashes, planar-reflection water with ripple distortion, procedural sky (HDR moon, twinkling stars), drifting mist, tree silhouettes, sync waves, lantern pointer, presets Chaos/Meadow/Unison/Tide, live synchrony meter, generative WebAudio (crickets that quantize to the swarm beat, pads, shimmer chimes), bloom + grade pass, adaptive quality, snapshots, touch support.

Let me write the demo file now.

Order of code in module:

1. imports
2. config/state
3. renderer/scene/camera/controls
4. textures (canvas)
5. sky
6. water reflector
7. ground
8. grass
9. trees
10. mist
11. fireflies
12. rings
13. lantern
14. lights uniform shared (uLights array of Vector4 shared across materials — same array object reference works for multiple ShaderMaterials? Each material has its own uniforms dict but values can reference the same Vector4 instances — yes, share the array of Vector4 objects.)
15. sim
16. audio
17. UI
18. events
19. animate
20. resize/adaptive/snapshot

Shared uniforms object:

Use same uniform objects in multiple materials — allowed (each material reads .value at render).

Grass vertex shader:

Wait — grass lighting at vertex level: blade has only 10 verts, glow pools ~2m radius vs blade 1m tall — vertex resolution along blade 0.25m — fine.

Grass fragment:

Grass placement: rejection sample in disc radius 44, density higher center; reeds near radius 30..40 ring (water edge) + clumps. Total max 60000: 52000 grass + 8000 reed.

Ground shader (circle radius 48): fragment: noise patches of mud/moss: col = mix(#0a140c, #12200f, fbm); glow loop same 24 lights + lantern; radial alpha fade 40→47 (transparent true); fog by distance.

Firefly shaders as planned.

Sky: sphere 360 BackSide.

Water: Reflector 500x500 plane.

Trees: 7 planes.

Mist: instanced 12 quads flat.

Rings: pool 8.

Lantern: Sprite additive.

Sim code:

update(dt):

Movement detail:

Top-24 lights: collect indices with intensity>0.06 into array with intensity, sort desc, take 24, fill lightVecs; zero rest.

Pulse:

Clamping to 0.999 causes all to fire together next frame — good cascade start.

Lantern pulse: every 1.15s if pointerFresh: pulseAt(lantern, 8, 0.30+eps*0.5, quiet) with small ring, no sound (or very soft tick every pulse? skip).

Tide: every 7s: side alternates: px = ±26, pz = rand(-10,10), pulseAt(px, 1.5, pz, 18, 0.5) + soft chime.

Audio module as planned.

UI wiring: standard.

Animate:

Pause? Not needed; skip pause button (keep UI lean). Actually 'P' pause could be nice but skip.

Bloom: UnrealBloomPass(res, strength .9, radius .55, threshold .75). Glow slider sets strength 0..1.6.

Grade pass after bloom, then OutputPass.

Now, potential pitfall: Reflector + EffectComposer RenderPass — fine.

Reflector plane at y=0 with ground disc at y=0.03 above covering center — reflection visible only outside disc fade. Good.

Also camera maxPolarAngle 1.45 (~83°) keeps above water.

Snapshot needs composer.render() then toDataURL — with OutputPass last, canvas has final image. OK.

Now write it all. Also the index.html update.

Let me count GLSL loops constants: for (int i = 0; i < 24; i++) fine.

Uniform vec4 array in three: uniforms: { uLights: { value: [Vector4 x24] } } — three handles arrays of Vector4.

In ground fragment same loop.

Water: I said skip lights; but lantern pool on water would be nice — mirror shows lantern sprite anyway. Skip.

Mist shader:

NormalBlending, transparent, depthWrite false. Drift: offset uv by time (done). Also move whole mist quads? uv scroll enough.

Tree texture function:

Trees: for i in 7: angle = i/72π + jitter; r = 58+rand30; h = 20+rand14; plane (h0.5, h); position y=h/2-0.2; lookAt center (rotateY). MeshBasicMaterial({map, alphaTest:0.4, side:DoubleSide, fog:false}) — MeshBasic unlit → dark silhouette. Slight color tint #9fb4c8*0.2? Basic material color multiplies texture: set color 0x8a97a8? That lightens? color multiplies — texture dark already; keep white.

Wait — with alphaTest, reflections work fine.

Lantern texture: radial gradient canvas 128: center rgba(255,220,150,1) → transparent.

Ring shader:

RingGeometry(inner .92, outer 1, 96): uv planar — compute r from uv. scale mesh = radius*uT+0.5. opacity via alpha. Additive, depthWrite false, flat rotX -π/2, y=0.25.

Ring pool update: each active ring: uT += dt/1.4; when >1 deactivate (visible=false).

Firefly vertex (instanced):

Fragment:

Additive blending: gl_FragColor rgb added; alpha ignored with AdditiveBlending? THREE.AdditiveBlending: src=SRC_ALPHA? Actually THREE.AdditiveBlending = src RGB * srcAlpha + dst? In three: AdditiveBlending → blendSrc SrcAlphaFactor, blendDst OneFactor. So rgb = alpha. Set alpha = afade and rgb = col without premult... Let me just output vec4(col*(1.2+2.6vFlash), afade). With SrcAlpha,One: result = colintensitya + dst. Good.

Hmm core smoothstep: 1.0 - smoothstep(0.0, 0.30, d) — at d=0 → 1. fine.

Sky shader:

Hmm — point-in-cell: brightness falloff with distance from cell center: float s = max(0.0, 1.0 - length(f)*2.2); s=s*s; star = step-ish gate * s. Gate: float gate = smoothstep(0.986, 0.995, h); twinkle: 0.6+0.4*sin(uTime*(1.0+h*3.0)+h*50.0). col += vec3(0.75,0.85,1.0)gatestwinkle1.4 * smoothstep(0.0,0.15,d.y) (fade at horizon).

Milky way band: vec3 bn = normalize(vec3(0.4,0.2,0.9)); float band = exp(-pow(dot(d,bn),2.0)*6.0); col += vec3(0.05,0.07,0.11)*band*fbm2(vec2(d.x,d.z)*6.0+3.0)*0.8; subtle.

Moon:

cos(1°)=0.99985, cos(2°)=0.99939. Moon angular ~0.5° real but artistic bigger: use cos range: inner 0.99965 (1.5°) outer 0.99985(0.99°)... disc = smoothstep(0.99955,0.99975,mdot). Craters: build moon local basis: mu = normalize(cross(uMoonDir, vec3(0,1,0))), mv = cross(mu, uMoonDir); vec2 mp = vec2(dot(d,mu), dot(d,mv))90.0; float cr = fbm2(mp1.4+7.0); moonCol = vec3(0.98,0.97,0.90)(0.75+0.25cr); col += moonCol * disc * 3.2; Halo: col += vec3(0.55,0.62,0.72) * pow(max(mdot,0.0), 900.0) * 1.4; wide: + vec3(0.2,0.26,0.34)*pow(max(mdot,0.0),60.0)*0.35;

Below horizon: col = mix toward deep (d.y<0): col = mix(col, vec3(0.004,0.010,0.016), smoothstep(0.0,-0.2,d.y)).

Sky sphere radius 380, camera far 1000.

Moon dir: normalize(vec3(-0.45, 0.38, -0.62)) — over water beyond trees. Also moonlight dir for ground sheen: skip.

Water moon glitter: add in water fragment: reflect dir approx: use uMoonDir uniform in water too: glitter = pow(max(dot(reflect(-V, n), moonDir),0), 400)... with n from ripple (mostly up). Add vec3(0.9,0.9,0.8)glitter0.6. Nice touch. n = normalize(vec3(grad.x2.0, 1.0, grad.y*2.0)).

Water fragment full:

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I've used 66% of the time budget already?! That's concerning — I need to move fast. Let me validate the JS syntax and GLSL quickly, then update the index and finish.

Quick validation: extract the module script and run node --check. Also check GLSL brace balance. Then update index.html. Then done.

85% of time used. I need to finish NOW. Quick sanity checks I wanted: smoothstep edge order — I used smoothstep(0.0, 0.32, d) etc, all ascending, good. One concern: smoothstep(0.99950, 0.99972, mdot) fine.

One real bug risk: in the Reflector custom shader, I assigned reflector.material.uniforms.uTime = uTime; — replacing the uniform object with shared one. That works since Reflector only touches tDiffuse/textureMatrix. OK.

Another: gradePass = new ShaderPass({...}) — ShaderPass accepts a shader object with uniforms/vertexShader/fragmentShader. Yes.

new UnrealBloomPass(res, params.glow, 0.55, 0.78) — strength from slider bound. OK.

bindSlider('density', ...) calls applyDensity which uses tiers[tier] — defined before use at runtime (applyTier called at end). Fine.

Now update the main index.html with the 026 card, then success. Do it immediately with replace_in_file.

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