Headless OpenGL Rendering using SSH and X11 forwarding

[Adam Jackson]

12290 is indeed EGL_BAD_ACCESS, and it's pretty much impossible for Mesa's
eglInitialize to return that, so (if I had to guess) you have nvidia's
driver installed as well, and (extra guessing now) nvidia's EGL only works
with connections to the local machine and not over the network. Mesa
shouldn't have that problem because it would select llvmpipe instead of a
native driver in that scenario, I think.

If "render to png" really is what you're trying to accomplish you might do
better to use EGL_EXT_platform_device to get a direct connection to the GPU
without involving a display server.

- ajax

On Tue, Mar 7, 2023 at 8:17 PM Richard Haney <compsci2011 at gmail.com> wrote:

> Please help,
>
> I have been going around and around with this problem but cannot seem to
> make any headway. I hope that one of you OpenGL EGL experts can help. [image:
> :slight_smile:]
>
> I have created a program that uses OpenGL EGL (version 1.5) with OpenGL 3
> that successfully renders an offscreen triangle and saves it to an image
> file (PNG) when I ssh *without* X11 forwarding on my Linux (Ubuntu 22.04)
> machine.
>
> However when I try the same thing using ssh *with* X11 forwarding enabled
> I get the following EGL error when I call eglInitialize(…): 12290 (I
> *think* is EGL_BAD_ACCESS).
>
> This seems really weird and I hope it is something simple that I am just
> not currently seeing.
>
> I really like using OpenGL with EGL but need a way to remedy this
> situation if possible. Is there a way for EGL to determine if X11
> forwarding is being employed and to ignore it or some other solution?
>
> The snippet of relevant C++ code follows, with area where error occurs
> marked:
>
> #include <iostream> #include <cstdlib> #include <EGL/egl.h> #define
> EGL_EGLEXT_PROTOTYPES #define GL_GLEXT_PROTOTYPES #include <EGL/eglext.h>
> #include <GL/gl.h> ... EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
> if(display == EGL_NO_DISPLAY) { std::cerr << "Failed to get EGL display: "
> << eglGetError() << std::endl; exit(EXIT_FAILURE); } EGLint major; EGLint
> minor; if(eglInitialize(display, &major, &minor) == EGL_FALSE) { // ERROR
> 12290 is generated here std::cerr << "Failed to initialize EGL: " <<
> eglGetError() << std::endl; exit(EXIT_FAILURE); } ...
>
>
> Any help would be greatly appreciated.
>
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