Modern Web Shader Expert (TSL, WGSL, Compute Shaders & GLSL)

English | Bahasa Indonesia

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<a name="english"></a>

English

Orchestration & Integration

Connects and orchestrates with relevant domain skills:

• web-3d-graphics-expert — WebGPU/WebGL scene rendering and NodeMaterial binding.
• web-game-engine-expert — Physics simulations, particle systems, and VFX materials.
• ui-ux-pro-max — Modern visual effects, glassmorphism, and screen-space distortion.
• performance-web-vitals — GPU profiling, draw call reduction, and compute shader optimization.

Description

Production-grade guidance for authoring, compiling, and optimizing GPU shaders for modern web applications. Focuses on the cutting-edge TSL (Three Shading Language) node system which cross-compiles to both WGSL (WebGPU) and GLSL (WebGL2), standalone WGSL Compute Shaders for parallel processing (particles, boids, simulation), and legacy GLSL optimization.

Trigger Conditions

Activate this skill when the user is:

• Writing custom shader materials in Three.js or Babylon.js.
• Refactoring legacy GLSL shaders to Three Shading Language (TSL) or WebGPU WGSL.
• Implementing WebGPU Compute Shaders (@compute workgroups, storage buffers).
• Creating procedural VFX: fluid simulations, volumetric clouds, noise-based terrain, or holographic shields.
• Designing post-processing screen passes (bloom, chromatic aberration, SSAO/GTAO, depth of field).
• Optimizing GPU bottlenecks, thread divergence, or ALU instruction counts.

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Modern Web Shader Paradigms (2026)

Paradigm	Target API	Key Advantages	When to Use
TSL (Three Shading Language)	WebGPU + WebGL2	Cross-compiles node trees to WGSL and GLSL; type-safe JavaScript/TypeScript syntax.	Default standard for modern Three.js (r170+) materials and post-processing.
WGSL (WebGPU Shading Language)	WebGPU native	Direct GPU memory access, structured storage buffers, atomic operations.	Raw WebGPU apps, Babylon.js WebGPU compute, custom WebGPU pipelines.
Compute Shaders	WebGPU	General-purpose GPU (GPGPU) computing; runs without rasterization or vertex buffers.	100,000+ particle systems, cloth physics, fluid simulation, GPU boids.
GLSL (ES 3.0)	WebGL2 fallback	Universal device compatibility on legacy hardware.	Legacy Three.js/Babylon.js projects and fallback pipelines.

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1. Three Shading Language (TSL) Node System

TSL replaces string-concatenated GLSL with modular, type-safe node expressions that Three.js automatically compiles to WGSL on WebGPU and GLSL on WebGL2.

import * as THREE from 'three/webgpu';
import { Fn, float, vec3, color, uv, time, positionLocal, sin, uniform } from 'three/tsl';

// Define custom dynamic uniforms
const uFrequency = uniform(3.0);
const uSpeed = uniform(1.5);

// Reusable TSL shader function (Node-based)
const waterWave = Fn(([freq, spd]) => {
  const coord = uv();
  const wave = sin(coord.x.mul(freq).add(time.mul(spd)))
    .add(sin(coord.y.mul(freq).add(time.mul(spd))))
    .mul(0.5);
  return wave;
});

// Vertex Position displacement in TSL
const displacedPosition = Fn(() => {
  const wave = waterWave(uFrequency, uSpeed);
  const newPos = positionLocal.add(vec3(0.0, wave.mul(0.2), 0.0));
  return newPos;
});

// Create Node Material
const oceanMaterial = new THREE.MeshStandardNodeMaterial();
oceanMaterial.positionNode = displacedPosition();
oceanMaterial.colorNode = Fn(() => {
  const wave = waterWave(uFrequency, uSpeed);
  const baseColor = color(0x004488);
  const foamColor = color(0x88eeff);
  return baseColor.mix(foamColor, wave.add(0.5));
})();

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2. WebGPU Compute Shaders (GPGPU Parallel Processing)

Compute shaders run arbitrary mathematical workloads across thousands of GPU threads simultaneously:

import * as THREE from 'three/webgpu';
import { Fn, float, vec3, uniform, storage, instanceIndex } from 'three/tsl';

const PARTICLE_COUNT = 65536;

// Create GPU Storage Buffers
const positionBuffer = new THREE.StorageBufferAttribute(new Float32Array(PARTICLE_COUNT * 3), 3);
const velocityBuffer = new THREE.StorageBufferAttribute(new Float32Array(PARTICLE_COUNT * 3), 3);

const posStorage = storage(positionBuffer, 'vec3', PARTICLE_COUNT);
const velStorage = storage(velocityBuffer, 'vec3', PARTICLE_COUNT);

// TSL Compute Kernel (executes per particle on GPU)
const computeParticles = Fn(() => {
  const index = instanceIndex;
  const pos = posStorage.element(index);
  const vel = velStorage.element(index);

  // Update position based on velocity
  pos.addAssign(vel.mul(0.016));

  // Bounce off boundaries [-5, 5]
  vel.y.assign(pos.y.lessThan(-5.0).select(vel.y.abs(), vel.y));
  vel.y.assign(pos.y.greaterThan(5.0).select(vel.y.abs().negate(), vel.y));
})().compute(PARTICLE_COUNT);

// In the render loop:
// renderer.compute(computeParticles);
// renderer.render(scene, camera);

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3. High-Performance Shader Rules (GPU Architecture)

1. Eliminate Branching Divergence:

   • GPU threads execute in lockstep warps (NVIDIA: 32 threads, AMD/Apple: 32-64 threads).
   • If threads inside the same warp take different branches in an if/else, both paths are evaluated serially, destroying throughput.
   • Use Math Primitives: Replace branches with step(), smoothstep(), mix(), clamp(), or select().

   // BAD: Divergent GPU branch
   if (vDepth > 0.5) { color = vec3(1.0); } else { color = vec3(0.0); }
   
   // GOOD: Branchless step function
   color = vec3(step(0.5, vDepth));
   

2. Precision Management:

   • Always specify precision for mobile GPUs.
   • Use mediump (16-bit float) for colors, normal vectors, and UVs to gain 2x arithmetic throughput and save bandwidth.
   • Reserve highp (32-bit float) for world-space coordinates and depth calculations.

3. Precompute on CPU or Vertex Shader:

   • Never compute values in the fragment shader (millions of pixels) that are constant across the mesh or linear across vertices.
   • Move matrix inversions, static lighting directions, or uniform transformations to the CPU or Vertex stage.

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<a name="bahasa-indonesia"></a>

Bahasa Indonesia

Integrasi Orkestrasi

Terhubung dan mengorkestrasi skill domain yang relevan:

• web-3d-graphics-expert — Rendering scene WebGPU/WebGL dan integrasi NodeMaterial.
• web-game-engine-expert — Simulasi fisika, sistem partikel, dan material efek game.
• ui-ux-pro-max — Efek visual modern, glassmorphism, dan distorsi screen-space.
• performance-web-vitals — Profiling GPU, optimasi draw call, dan compute shader.

Deskripsi

Panduan produksi untuk menulis, mengompilasi, dan mengoptimalkan shader GPU untuk aplikasi web modern. Fokus pada sistem node TSL (Three Shading Language) yang dapat dikompilasi silang menjadi WGSL (WebGPU) dan GLSL (WebGL2), Compute Shader WGSL mandiri untuk pemrosesan paralel GPU skala masif (partikel, boids, simulasi cairan), dan optimasi GLSL.

Kondisi Pemicu

Aktifkan skill ini ketika pengguna:

• Menulis custom shader material pada Three.js atau Babylon.js.
• Merefaktor shader GLSL lama menjadi Three Shading Language (TSL) atau WebGPU WGSL.
• Mengimplementasikan WebGPU Compute Shader (@compute workgroups, storage buffers).
• Membuat efek visual prosedural (simulasi air, awan volumetrik, medan prosedural, perisai hologram).
• Merancang post-processing passes (bloom, chromatic aberration, SSAO, depth of field).
• Mengatasi bottleneck GPU, thread divergence, atau instruksi ALU berlebih.

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Prinsip Utama Shader Modern

1. Adopsi TSL (Three Shading Language):

   • Hindari menulis shader dalam bentuk string concatenation GLSL mentah pada proyek modern. Gunakan TSL (Fn, color, uv, positionLocal). TSL menjaga keamanan tipe (type-safety) dan otomatis menghasilkan WGSL atau GLSL sesuai runtime.

2. GPGPU dengan Compute Shader:

   • Manfaatkan WebGPU Compute Shader untuk kalkulasi ribuan partikel atau simulasi matematika tanpa melalui tahap rasterisasi atau vertex buffer tradisional.

3. Aturan Anti-Branching (Branchless Shader):

   • GPU mengeksekusi instruksi dalam kelompok thread (warp/wavefront). Percabangan if/else yang tidak seragam akan memaksa GPU mengeksekusi kedua cabang secara berurutan (branch penalty).
   • Gunakan fungsi matematika seperti step(), smoothstep(), dan mix() alih-alih percabangan logika kondisional.

4. Manajemen Presisi:

   • Gunakan mediump (16-bit float) untuk warna, koordinat UV, dan vektor normal untuk melipatgandakan kecepatan komputasi pada GPU smartphone.
   • Gunakan highp (32-bit float) hanya untuk posisi ruang dunia (world space) dan perhitungan kedalaman (depth).