android_gles2_init.cpp

EGLint major, minor, count, n, size, w, h, format;
    EGLDisplay display = nullptr;
    EGLSurface surface;
    EGLContext context;
    EGLConfig *configs;
    EGLConfig config = nullptr;
    EGLBoolean result = EGL_FALSE;

    static const EGLint config_attribs[] = {
            EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
            EGL_RED_SIZE, 8,
            EGL_GREEN_SIZE, 8,
            EGL_BLUE_SIZE, 8,
            EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
            EGL_NONE
    };

    static const EGLint context_attribs[] = {
            EGL_CONTEXT_CLIENT_VERSION, 2,
            EGL_NONE
    };

    display = eglGetDisplay((EGLNativeDisplayType) display);
    if (display == EGL_NO_DISPLAY) {
        // TODO
        return -1;
    }

    result = eglInitialize(display, &major, &minor);
    if (result != EGL_TRUE) {
        // TODO
        return -1;
    }

    LOGI("EGL successfuly initialized!");
    LOGI("EGL major: %d, minor %d", major, minor);

    eglGetConfigs(display, nullptr, 0, &count);
    printf("EGL has %d configs", count);

    configs = new EGLConfig[count]();
    eglChooseConfig(display, config_attribs, configs, count, &n);

    for (int i = 0; i < n; i++) {
        eglGetConfigAttrib(display, configs[i], EGL_BUFFER_SIZE, &size);
        eglGetConfigAttrib(display, configs[i], EGL_RED_SIZE, &size);

        LOGD("Buffer size for config %d is %d", i, size);
        LOGD("Red size for config %d is %d", i, size);

        // just choose the first one
        config = configs[i];
        break;
    }

    eglGetConfigAttrib(display, config, EGL_NATIVE_VISUAL_ID, &format);
    surface = eglCreateWindowSurface(display, config, engine->app->window, nullptr);
    context = eglCreateContext(display, config, EGL_NO_CONTEXT, context_attribs);

    result = eglMakeCurrent(display, surface, surface, context);
    if (result == EGL_FALSE) {
        // TODO
        return -1;
    }

    GlInfo();

    glEnable(GL_CULL_FACE);
    glDisable(GL_DEPTH_TEST);

    eglQuerySurface(display, surface, EGL_WIDTH, &w);
    eglQuerySurface(display, surface, EGL_HEIGHT, &h);

    engine->display = display;
    engine->context = context;
    engine->surface = surface;
    engine->width = w;
    engine->height = h;
    engine->state.angle = 0;

    return 0;