OpenGL & Ubuntu 14.04 No rendering after Lock Screen

Question

My OpenGL version 4.5.0 on Ubuntu 14.04. VBO and shaders are used. The OpenGL not rendering correctly after lock screen (black with a few color lines, looks like glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT) not working). I tried both offline rendering (FBO save frame to picture) and online rendering (draw frame on window).

Any suggestion would be appreciated.

Answer 1

Render to an FBO not to a window-. The contents of a window are undefined for the pixels that don't pass the pixel ownership test (ie windows obscured, for example by the screen locker overlay).

Depending on the OpenGL implementation and environment you still may require a window for creating a context. But recently it's become possible to create working OpenGL contexts without requring a display server to run.

For NVidia see https://devblogs.nvidia.com/parallelforall/egl-eye-opengl-visualization-without-x-server/