2nd/10_Wiki/Topic_Programming/Frontend/WebGL API.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-webgl-api	WebGL API	10_Wiki/Topics	verified	self	WebGL WebGL API WebGL 1.0 WebGL 2.0	none	A	0.9	applied	webgl graphics gpu gles		2026-05-10	pending	language framework JavaScript/GLSL Web Platform

WebGL API

매 한 줄

"매 OpenGL ES 의 web — canvas 의 GPU draw". WebGL 매 OpenGL ES 2.0 (WebGL1) / ES 3.0 (WebGL2) binding 의 browser. 2026 매 WebGPU rising 매 WebGL 매 still ubiquitous — fallback / wide compatibility 의 사용.

매 핵심

매 pipeline

• Vertex shader: per-vertex transform — clip space.
• Rasterizer: triangles → fragments.
• Fragment shader: per-pixel color.
• Framebuffer: render target — default canvas / FBO offscreen.

매 핵심 objects

• Buffer (ARRAY_BUFFER, ELEMENT_ARRAY_BUFFER): vertex / index data.
• Texture (2D / cube / 3D-WebGL2 / array-WebGL2).
• Program: vertex + fragment shader linked.
• VAO (WebGL2): vertex attribute state.
• UBO (WebGL2): uniform block — efficient bulk uniform.
• Framebuffer / Renderbuffer: offscreen render targets.

매 응용

1. 3D libraries: Three.js / Babylon.js / PlayCanvas.
2. 2D accelerated: PixiJS / Konva.
3. Data viz: deck.gl / Mapbox GL / regl.
4. Games / interactive: itch.io HTML5 / Unity WebGL build.

💻 패턴

매 minimal triangle

const canvas = document.querySelector('canvas');
const gl = canvas.getContext('webgl2');

const vs = `#version 300 es
in vec2 a_pos;
void main() { gl_Position = vec4(a_pos, 0.0, 1.0); }`;

const fs = `#version 300 es
precision highp float;
out vec4 fragColor;
void main() { fragColor = vec4(1.0, 0.5, 0.2, 1.0); }`;

function compile(type, src) {
  const s = gl.createShader(type);
  gl.shaderSource(s, src); gl.compileShader(s);
  if (!gl.getShaderParameter(s, gl.COMPILE_STATUS)) throw gl.getShaderInfoLog(s);
  return s;
}
const prog = gl.createProgram();
gl.attachShader(prog, compile(gl.VERTEX_SHADER, vs));
gl.attachShader(prog, compile(gl.FRAGMENT_SHADER, fs));
gl.linkProgram(prog);

const vao = gl.createVertexArray();
gl.bindVertexArray(vao);
const vbo = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0, 0.5, -0.5, -0.5, 0.5, -0.5]), gl.STATIC_DRAW);
const loc = gl.getAttribLocation(prog, 'a_pos');
gl.enableVertexAttribArray(loc);
gl.vertexAttribPointer(loc, 2, gl.FLOAT, false, 0, 0);

gl.useProgram(prog);
gl.drawArrays(gl.TRIANGLES, 0, 3);

Texture upload

const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, w, h, 0, gl.RGBA, gl.UNSIGNED_BYTE, pixels);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.generateMipmap(gl.TEXTURE_2D);

Instanced rendering (WebGL2)

gl.vertexAttribDivisor(instanceLoc, 1); // advance per instance
gl.drawArraysInstanced(gl.TRIANGLES, 0, 6, 10000); // 10k instances 1 draw call

Uniform Buffer Object (WebGL2)

const ubo = gl.createBuffer();
gl.bindBuffer(gl.UNIFORM_BUFFER, ubo);
gl.bufferData(gl.UNIFORM_BUFFER, mat4Buffer, gl.DYNAMIC_DRAW);
const idx = gl.getUniformBlockIndex(prog, 'Camera');
gl.uniformBlockBinding(prog, idx, 0);
gl.bindBufferBase(gl.UNIFORM_BUFFER, 0, ubo);

Framebuffer (offscreen / render-to-texture)

const fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA16F, w, h, 0, gl.RGBA, gl.HALF_FLOAT, null);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
// 매 render → tex, then post-process

Transform Feedback (WebGL2 GPU compute-ish)

gl.bindBufferBase(gl.TRANSFORM_FEEDBACK_BUFFER, 0, outBuf);
gl.beginTransformFeedback(gl.POINTS);
gl.drawArrays(gl.POINTS, 0, particleCount);
gl.endTransformFeedback();

Context loss handling

canvas.addEventListener('webglcontextlost', (e) => { e.preventDefault(); });
canvas.addEventListener('webglcontextrestored', () => { rebuildResources(); });

매 결정 기준

상황	WebGL vs WebGPU
2026 wide compatibility	WebGL2 — Safari iOS / older Android
Compute shader	WebGPU
Multi-pass complex	WebGPU 매 cleaner state model
Existing Three.js / Babylon	WebGL2 fallback + WebGPU primary
Simple 2D accel	WebGL2 / 2D canvas
AAA-grade graphics	WebGPU

기본값: Three.js with WebGPURenderer + WebGL2 fallback.

🔗 Graph

• 부모: OpenGL ES
• 변형: WebGPU
• 응용: Threejs · Babylonjs
• Adjacent: GLSL · OffscreenCanvas

🤖 LLM 활용

언제: cross-browser 3D / 2D GPU accel / data viz / WebGPU 의 fallback. 언제 X: heavy compute (no compute shader in WebGL) / cutting-edge graphics — WebGPU 사용.

❌ 안티패턴

• State thrash: bind/unbind every draw — batch by program/texture.
• Sync readback: readPixels 매 GPU stall — use PBO async (WebGL2).
• No VAO: re-binding attributes every draw — VAO 매 cache.
• Uniform per draw call: UBO 의 bulk update / instancing.
• Premultiply confusion: alpha blending 의 incorrect — UNPACK_PREMULTIPLY_ALPHA_WEBGL.

🧪 검증 / 중복

• Verified (Khronos WebGL 1.0/2.0 spec / MDN WebGL API).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — pipeline, VAO, UBO, FBO, instancing, transform feedback