2nd/10_Wiki/Topic_Programming/Frontend/OpenGL ES.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-opengl-es	OpenGL ES	10_Wiki/Topics	verified	self	GLES OpenGL for Embedded Systems	none	A	0.9	applied	graphics mobile gpu rendering		2026-05-10	pending	language framework GLSL OpenGL ES 3.2

OpenGL ES

매 한 줄

"매 mobile/embedded GPU 의 lingua franca — 2026 에도 매 Android/legacy iOS 매 핵심 graphics API". Khronos Group 매 2003 발표 이래로 매 모바일 3D rendering standard, 매 modern Vulkan 으로 매 점진적 migration 진행 중이지만 매 GLES 3.2 매 widespread support (99%+ Android devices).

매 핵심

매 versions

• GLES 1.x (2003): Fixed-function pipeline. 매 deprecated.
• GLES 2.0 (2007): Programmable shaders (vertex + fragment). 매 baseline.
• GLES 3.0 (2012): Transform feedback, instancing, MSAA, ETC2 textures.
• GLES 3.1 (2014): Compute shaders, indirect draws, SSBO.
• GLES 3.2 (2015): Geometry/tessellation shaders, ASTC, debug output.

매 platform support

• Android: 매 native API (NDK + EGL). 매 99%+ devices support GLES 3.0+.
• iOS: 매 deprecated since iOS 12 (Metal preferred), 매 still functional.
• WebGL: 매 GLES 2.0/3.0 subset over JavaScript.
• Embedded Linux: 매 Mali/Adreno/PowerVR drivers.

매 응용

1. Mobile games (Unity/Unreal default backend on legacy Android).
2. Map rendering (Mapbox GL, Google Maps).
3. AR frameworks (ARCore rendering layer).
4. Video filters (Snapchat, Instagram shaders).

💻 패턴

EGL context init (Android NDK)

EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
eglInitialize(display, NULL, NULL);

EGLint attribs[] = {
    EGL_RENDERABLE_TYPE, EGL_OPENGL_ES3_BIT,
    EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
    EGL_RED_SIZE, 8, EGL_GREEN_SIZE, 8, EGL_BLUE_SIZE, 8,
    EGL_DEPTH_SIZE, 24,
    EGL_NONE
};
EGLConfig config;
EGLint num_configs;
eglChooseConfig(display, attribs, &config, 1, &num_configs);

EGLint ctx_attribs[] = { EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE };
EGLContext context = eglCreateContext(display, config, EGL_NO_CONTEXT, ctx_attribs);
EGLSurface surface = eglCreateWindowSurface(display, config, native_window, NULL);
eglMakeCurrent(display, surface, surface, context);

Vertex + fragment shader (GLES 3.0)

// vertex.glsl
#version 300 es
layout(location = 0) in vec3 a_position;
layout(location = 1) in vec2 a_uv;
uniform mat4 u_mvp;
out vec2 v_uv;
void main() {
    v_uv = a_uv;
    gl_Position = u_mvp * vec4(a_position, 1.0);
}

// fragment.glsl
#version 300 es
precision mediump float;
in vec2 v_uv;
uniform sampler2D u_tex;
out vec4 fragColor;
void main() {
    fragColor = texture(u_tex, v_uv);
}

Shader compile + link

GLuint compile(GLenum type, const char *src) {
    GLuint s = glCreateShader(type);
    glShaderSource(s, 1, &src, NULL);
    glCompileShader(s);
    GLint ok; glGetShaderiv(s, GL_COMPILE_STATUS, &ok);
    if (!ok) { char log[512]; glGetShaderInfoLog(s, 512, NULL, log); LOGE("%s", log); }
    return s;
}
GLuint vs = compile(GL_VERTEX_SHADER, vsrc);
GLuint fs = compile(GL_FRAGMENT_SHADER, fsrc);
GLuint prog = glCreateProgram();
glAttachShader(prog, vs); glAttachShader(prog, fs);
glLinkProgram(prog);

VBO + VAO setup (GLES 3.0)

GLuint vao, vbo;
glGenVertexArrays(1, &vao);
glGenBuffers(1, &vbo);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void*)(3*sizeof(float)));
glEnableVertexAttribArray(1);

Texture upload

GLuint tex;
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glGenerateMipmap(GL_TEXTURE_2D);

Compute shader (GLES 3.1+)

#version 310 es
layout(local_size_x = 16, local_size_y = 16) in;
layout(rgba8, binding = 0) uniform image2D u_img;
void main() {
    ivec2 p = ivec2(gl_GlobalInvocationID.xy);
    vec4 c = imageLoad(u_img, p);
    imageStore(u_img, p, vec4(1.0 - c.rgb, c.a)); // invert
}

glUseProgram(compute_prog);
glBindImageTexture(0, tex, 0, GL_FALSE, 0, GL_READ_WRITE, GL_RGBA8);
glDispatchCompute(w/16, h/16, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);

Framebuffer object (offscreen render)

GLuint fbo, color, depth;
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glGenTextures(1, &color);
glBindTexture(GL_TEXTURE_2D, color);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
glGenRenderbuffers(1, &depth);
glBindRenderbuffer(GL_RENDERBUFFER, depth);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, w, h);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth);

매 결정 기준

상황	Approach
New mobile project (2026)	Vulkan (Android) / Metal (iOS)
Cross-platform legacy support	OpenGL ES 3.0
Web target	WebGL 2.0 (GLES 3.0 subset) / WebGPU
Compute on mobile	GLES 3.1 compute or Vulkan compute
Maximum device reach	GLES 2.0 (단 functionality 제약)

기본값: 매 new code 매 Vulkan, 매 legacy support 매 GLES 3.0.

🔗 Graph

• 부모: GPU-Programming
• 변형: Vulkan · Metal · WebGL · WebGPU
• 응용: Mobile-Augmented-Reality
• Adjacent: GLSL

🤖 LLM 활용

언제: 매 cross-platform mobile graphics, 매 WebGL/embedded targeting, 매 legacy Android (API < 24) 매 support 필요. 언제 X: 매 modern Android-only (Vulkan), 매 iOS-only (Metal), 매 desktop-first (Vulkan/DX12).

❌ 안티패턴

• glGetError 매 polling 매 hot loop: 매 sync stall — 매 KHR_debug callback 사용.
• 매 frame VBO 매 recreate: 매 GPU memory thrash — 매 persistent buffer + glBufferSubData.
• precision highp 매 fragment shader 남용: 매 mobile GPU 성능 hit — 매 mediump default.
• immediate mode mindset: 매 GLES 매 retained mode — 매 batch draw calls.
• driver-specific extensions 의존: 매 portability 깨짐 — 매 core spec 우선.

🧪 검증 / 중복

• Verified (Khronos OpenGL ES 3.2 spec, Android NDK docs).
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — full GLES API guide with EGL/shader/compute patterns