Details
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Bug
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Resolution: Out of scope
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P2: Important
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None
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5.14.0
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Ubuntu 18.04 (default desktop installation), Mesa version: OpenGL 3.1 Mesa 18.1.9 (git-f57f37f3ba)
Description
Used hellogl2 sample to reproduce the issue. Built it from source in QtCreator.
Here are the steps:
1. Launch the sample in the default desktop: it works.
2. Start VNC server with: vnc4server and see which display it occupies
3. Launch DISPLAY=:<number-of-vnc-display> hellogl2
Result: there are errors like that
qt.qpa.xcb: failed to initialize XRandr
qt.qpa.xcb: XKeyboard extension not present on the X server
qt.glx: qglx_findConfig: Failed to finding matching FBConfig for QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 0, redBufferSize 1, greenBufferSize 1, blueBufferSize 1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior QSurfaceFormat::SingleBuffer, swapInterval 1, colorSpace QSurfaceFormat::DefaultColorSpace, profile QSurfaceFormat::NoProfile)
Unsupported screen format: depth: 16, bits_per_pixel: 16, red_mask: 3f, blue_mask: f800
Using RGB16 fallback, if this works your X11 server is reporting a bad screen format.
and the app is black.
4. Get Mesa libGL.so* with Gallium or Xlib driver and put it into any directory
5. Launch DISPLAY=:<number-of-vnc-display> LD_LIBRARY_PATH=<path-to-mesa-dir> hellogl2
Result:
There is still an error but it looks not so severe:
qt.qpa.xcb: failed to initialize XRandr
qt.qpa.xcb: XKeyboard extension not present on the X server
Result:
Buttons and sliders appeared but the OpenGL widget is still black.
6. Launch: DISPLAY=:<number-of-vnc-display> LD_LIBRARY_PATH=<path-to-mesa-dir> glxgears
Result: it works.