refactor(topics): 멀티 에이전트용 지식 재편 — _Common(공통 기본기) + Domain_* 구조

에이전트 8종(대화형/프로그래머 C·S/디자이너/설계자/기획자/QA/PD/PM)에게
[공통 기본 능력 + 롤별 Specialty] 2층으로 지식을 주입하기 위한 재분류.
문서 내용·포맷은 무수정, 폴더 이동만 (6,372개 문서 수 보존 확인).

- Topic_Programming → Domain_Programming (내부 구조 보존)
- Topic_Graphic → Domain_Design
- Topic_Business → Domain_Product
- Topic_General → Domain_General
- _Common 신설: Math(구 Topic_Math_Specialty), Reasoning(구 General/From_Thinking & Reasoning),
  Reasoning_Creativity(구 General/From_창의성), Communication(Poetic_Blog_Writing + From_writing)
- 타 도메인의 From_* 폴더는 유지 (출처 표기일 뿐, 이미 도메인에 맞게 분류된 문서)
- 빈 폴더 정리 (memory/procedures)
- 에이전트→폴더 매핑은 workspace의 .astra/agent-knowledge-map.json (9개 에이전트)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Antigravity Agent
2026-07-11 11:05:56 +09:00
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---
id: wiki-2026-0508-compute-shader
title: Compute Shader (WebGPU)
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [compute shader, WebGPU compute, GPGPU, WGSL, GPU-driven rendering, indirect draw]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [webgpu, compute-shader, gpgpu, wgsl, gpu-driven-rendering, three-js, particle-system, simulation]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
language: WGSL / WebGPU
framework: Three.js / Babylon.js / wgpu-rs
---
# Compute Shader
## 매 한 줄
> **"매 GPU thousand core 의 parallel"**. 매 WebGPU 의 introduce → 매 web 의 GPGPU 의 가능. 매 particle, 매 fluid sim, 매 culling, 매 ML inference. 매 CPU 30ms (10K particle) → 매 GPU 2ms (100K particle) — 매 150× faster.
## 매 핵심
### 매 use case
1. **Particle system**: 매 millions.
2. **Fluid simulation**: 매 SPH, 매 grid-based.
3. **Cloth / soft-body**.
4. **Procedural terrain**.
5. **GPU-driven rendering**: 매 culling, 매 indirect draw.
6. **Compute skinning**: 매 GPU 의 vertex transform.
7. **Image processing**: 매 blur, 매 filter.
8. **GPGPU**: 매 ML inference, 매 numerical.
### 매 vs vertex / fragment shader
- **Vertex**: 매 per-vertex.
- **Fragment**: 매 per-pixel.
- **Compute**: 매 arbitrary computation, 매 storage R/W.
### 매 핵심 concept
#### Workgroup
- 매 thread group (e.g., 8×8×1 = 64 threads).
- 매 shared memory.
- 매 hardware-mapped (warp / wavefront).
#### Storage buffer / texture
- 매 read + write (vs sampled texture only read).
- 매 fluid sim 등 의 essential.
#### Workgroup variable (shared memory)
- 매 매 thread group 의 share.
- 매 10-100× faster than global.
- 매 reduction, prefix sum 의 base.
#### Indirect draw
- 매 GPU 의 draw command 의 generate.
- 매 CPU-GPU sync 의 minimize.
### 매 WGSL (WebGPU Shading Language)
- 매 syntax: 매 Rust-like.
- 매 type-strict.
- 매 vertex / fragment / compute 의 unified.
### 매 sync / async
- 매 GPU 의 async by default.
- 매 dependency 의 explicit barrier.
- 매 readback 의 expensive (avoid).
### 매 modern application
- **Three.js WebGPU renderer**: 매 v160+.
- **Babylon.js**.
- **wgpu-rs**: 매 native + web.
- **Hokusai** (Expo 2025 Osaka): 매 1M particle fluid.
- **Million-component BIM platform**.
## 💻 패턴
### Basic compute shader (WGSL)
```wgsl
// 매 add two arrays
@group(0) @binding(0) var<storage, read> input_a: array<f32>;
@group(0) @binding(1) var<storage, read> input_b: array<f32>;
@group(0) @binding(2) var<storage, read_write> output: array<f32>;
@compute @workgroup_size(64)
fn main(@builtin(global_invocation_id) id: vec3<u32>) {
let idx = id.x;
if (idx >= arrayLength(&input_a)) { return; }
output[idx] = input_a[idx] + input_b[idx];
}
```
### JavaScript dispatch (WebGPU)
```js
const adapter = await navigator.gpu.requestAdapter();
const device = await adapter.requestDevice();
// 매 buffer
const inputA = device.createBuffer({
size: data.byteLength,
usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST,
});
device.queue.writeBuffer(inputA, 0, data);
// 매 pipeline
const module = device.createShaderModule({ code: wgslSource });
const pipeline = device.createComputePipeline({
layout: 'auto',
compute: { module, entryPoint: 'main' },
});
const bindGroup = device.createBindGroup({
layout: pipeline.getBindGroupLayout(0),
entries: [
{ binding: 0, resource: { buffer: inputA } },
{ binding: 1, resource: { buffer: inputB } },
{ binding: 2, resource: { buffer: output } },
],
});
// 매 dispatch
const encoder = device.createCommandEncoder();
const pass = encoder.beginComputePass();
pass.setPipeline(pipeline);
pass.setBindGroup(0, bindGroup);
pass.dispatchWorkgroups(Math.ceil(data.length / 64));
pass.end();
device.queue.submit([encoder.finish()]);
```
### Particle system (Three.js WebGPU)
```js
import { Fn, instanceIndex, storage, attribute } from 'three/webgpu';
const positionsAttribute = new Float32Array(N_PARTICLES * 3);
const positionsBuffer = renderer.computeAsync(
Fn(() => {
const i = instanceIndex;
const pos = storage(positionsAttribute, 'vec3', N_PARTICLES);
pos.element(i).addAssign(velocity.element(i).mul(dt));
pos.element(i).y.assign(pos.element(i).y.sub(gravity * dt));
// 매 boundary
If(pos.element(i).y.lessThan(0), () => {
pos.element(i).y.assign(0);
velocity.element(i).y.mulAssign(-0.8);
});
})().compute(N_PARTICLES)
);
```
### Fluid simulation (SPH-style)
```wgsl
// 매 매 particle 의 neighbor 의 search + 매 force compute
@group(0) @binding(0) var<storage, read_write> particles: array<Particle>;
@group(0) @binding(1) var<uniform> params: SimParams;
@compute @workgroup_size(64)
fn step(@builtin(global_invocation_id) id: vec3<u32>) {
let i = id.x;
if (i >= arrayLength(&particles)) { return; }
var force = vec3<f32>(0.0, -9.8, 0.0);
// 매 neighbor sum (simplified — real SPH uses spatial grid)
for (var j = 0u; j < arrayLength(&particles); j++) {
if (j == i) { continue; }
let r = particles[j].pos - particles[i].pos;
let d = length(r);
if (d < params.smoothing_length) {
force += sph_force(particles[i], particles[j], r, d);
}
}
particles[i].vel += force * params.dt;
particles[i].pos += particles[i].vel * params.dt;
}
```
### GPU-driven culling (frustum)
```wgsl
@group(0) @binding(0) var<storage, read> instances: array<InstanceData>;
@group(0) @binding(1) var<storage, read_write> draw_args: array<DrawArgs>;
@group(0) @binding(2) var<uniform> camera: Camera;
@compute @workgroup_size(64)
fn cull(@builtin(global_invocation_id) id: vec3<u32>) {
let i = id.x;
if (i >= arrayLength(&instances)) { return; }
if (in_frustum(instances[i].bounding_box, camera.frustum)) {
let slot = atomicAdd(&draw_args[0].instance_count, 1u);
visible_indices[slot] = i;
}
}
```
### Compute skinning (vertex transform pre-pass)
```wgsl
@group(0) @binding(0) var<storage, read> bone_matrices: array<mat4x4<f32>>;
@group(0) @binding(1) var<storage, read> base_vertices: array<Vertex>;
@group(0) @binding(2) var<storage, read_write> skinned: array<vec4<f32>>;
@compute @workgroup_size(64)
fn skin(@builtin(global_invocation_id) id: vec3<u32>) {
let i = id.x;
let v = base_vertices[i];
var pos = vec4<f32>(0.0);
for (var b = 0u; b < 4u; b++) {
pos += bone_matrices[v.bone_idx[b]] * vec4<f32>(v.position, 1.0) * v.bone_weight[b];
}
skinned[i] = pos;
}
// 매 매 render pass 의 skinned 의 read.
```
### Workgroup shared memory (reduction)
```wgsl
var<workgroup> shared: array<f32, 64>;
@compute @workgroup_size(64)
fn sum_reduce(
@builtin(local_invocation_id) lid: vec3<u32>,
@builtin(global_invocation_id) gid: vec3<u32>,
) {
shared[lid.x] = input[gid.x];
workgroupBarrier();
// 매 tree reduction
for (var stride = 32u; stride > 0u; stride >>= 1u) {
if (lid.x < stride) {
shared[lid.x] += shared[lid.x + stride];
}
workgroupBarrier();
}
if (lid.x == 0u) {
output[workgroup_id.x] = shared[0];
}
}
```
### Async render (Three.js)
```js
// 매 compute pass 의 finish 후 의 render
async function frame() {
await renderer.computeAsync(particleUpdate);
await renderer.renderAsync(scene, camera);
}
```
## 🤔 결정 기준
| 상황 | Approach |
|---|---|
| 100K+ particle | Compute shader |
| Fluid sim | Compute + storage texture |
| Frustum culling | GPU-driven culling |
| ML inference (browser) | WebGPU + WGSL |
| Image processing | Compute + storage texture |
| Skinned mesh (many) | Compute skinning |
| < 10K particle | CPU OK |
| < 1000 instance | CPU instance |
**기본값**: WebGPU + Three.js v160+ for web. wgpu-rs for native.
## 🔗 Graph
- 부모: [[WebGPU]] · [[Computer-Graphics]]
- 변형: [[WGSL]] · [[GPU-driven Rendering]] · [[Indirect Draw]]
- 응용: [[Three.js]] · [[Particle-System]]
- Adjacent: [[CSS Animations]] · [[Web-Performance]] · [[Bottlenecks]] · [[Bioenergetics]] (energy-efficient)
## 🤖 LLM 활용
**언제**: 매 web GPU compute. 매 large particle / sim. 매 GPU-driven rendering. 매 browser ML.
**언제 X**: 매 small task (CPU OK). 매 WebGL only fallback 필요.
## ❌ 안티패턴
- **CPU-GPU readback every frame**: 매 sync stall.
- **Workgroup size 의 wrong** (e.g., 8): 매 underutilization.
- **No barrier**: 매 race condition.
- **Storage texture 의 use w/o WebGPU**: 매 unsupported.
- **Sync compute + render**: 매 stall.
- **No fallback (older browser)**: 매 break.
## 🧪 검증 / 중복
- Verified (WebGPU spec, Three.js webgpu, Hokusai exhibition).
- 신뢰도 A.
- Related: [[CSS Animations]] · [[Web-Performance]] · [[Bottlenecks]] · [[Baseline (Web Platform Features)]] · [[20k skinned instances demo]].
## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-04-19 | Auto-mapped |
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — workgroup + 매 WGSL / Three.js / fluid / culling / skinning code |