OpenGLES2 on Linux console

opengles2.c

#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <GLES2/gl2.h>
#include <assert.h>
#include <fcntl.h>
#include <gbm.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

int32_t __fd;
struct gbm_device *__gbm;
EGLDisplay __egl_dpy;
EGLContext __core_ctx;

void coInit()
{
	bool res;
	int32_t __fd = open("/dev/dri/renderD128", O_RDWR);
	assert(__fd > 0);

	__gbm = gbm_create_device(__fd);
	assert(__gbm != NULL);

	/* setup EGL from the GBM device */
	__egl_dpy = eglGetPlatformDisplay(EGL_PLATFORM_GBM_MESA, __gbm, NULL);
	assert(__egl_dpy != NULL);

	res = eglInitialize(__egl_dpy, NULL, NULL);
	assert(res);

	const char *egl_extension_st = eglQueryString(__egl_dpy, EGL_EXTENSIONS);
	assert(strstr(egl_extension_st, "EGL_KHR_create_context") != NULL);
	assert(strstr(egl_extension_st, "EGL_KHR_surfaceless_context") != NULL);

	static const EGLint config_attribs[] = {
		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
		EGL_NONE
	};
	EGLConfig cfg;
	EGLint count;

	res = eglChooseConfig(__egl_dpy, config_attribs, &cfg, 1, &count);
	assert(res);

	res = eglBindAPI(EGL_OPENGL_ES_API);
	assert(res);

	static const EGLint attribs[] = {
		EGL_CONTEXT_CLIENT_VERSION, 2,
		EGL_NONE
	};
	__core_ctx = eglCreateContext(__egl_dpy, cfg, EGL_NO_CONTEXT, attribs);
	assert(__core_ctx != EGL_NO_CONTEXT);

	res = eglMakeCurrent(__egl_dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, __core_ctx);
	assert(res);
}

void coTerm()
{
	eglDestroyContext(__egl_dpy, __core_ctx);
	eglTerminate(__egl_dpy);
	gbm_device_destroy(__gbm);
	close(__fd);
}