EGL example for voxl2

[John Keller]

I saw that the voxl2 supports OpenGLES 3.1 and I would like to port over some of our OpenGL code to run on the voxl2. I am starting off by trying to get EGL to initialize with the following program but it is failing on the call to eglInitialize with error 0x3001 which is EGL_NOT_INITIALIZED. I am building with gcc egl-query.c -o egl-query -lEGL.

Is there any examples of using EGL/OpenGL or does anyone know how to get this working?

Thank you

#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <stdio.h>

int main(void)
{
    EGLDisplay display;
    EGLint major, minor;

    display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
    if (display == EGL_NO_DISPLAY) {
        printf("eglGetDisplay failed\n");
        return 1;
    }

    if (!eglInitialize(display, &major, &minor)) {
        EGLint err = eglGetError();
        printf("eglInitialize failed (0x%x)\n", err);
        return 1;
    }

    printf("EGL initialized successfully\n");
    printf("EGL version: %d.%d\n", major, minor);

    const char* vendor     = eglQueryString(display, EGL_VENDOR);
    const char* version    = eglQueryString(display, EGL_VERSION);
    const char* extensions = eglQueryString(display, EGL_EXTENSIONS);
    const char* clientapis = eglQueryString(display, EGL_CLIENT_APIS);

    printf("EGL_VENDOR:      %s\n", vendor ? vendor : "(null)");
    printf("EGL_VERSION:     %s\n", version ? version : "(null)");
    printf("EGL_CLIENT_APIS: %s\n", clientapis ? clientapis : "(null)");
    printf("EGL_EXTENSIONS:\n%s\n", extensions ? extensions : "(null)");

    eglTerminate(display);
    return 0;
}