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  1. Qt
  2. QTBUG-139335

QtWebEngine based browser shows nothing with MESA LLVMpipe

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: P2: Important P2: Important
    • None
    • 6.9.1
    • WebEngine
    • None
    • Linux/X11

      I have something similar to QTBUG-136160 except it started with 6.9.1 and I am not using nvidia but mesa with software opengl.

      The webengine views are completly blank and the logs are filled with:

      Compositor returned null texture
      Backend texture is not a Vulkan texture.
      

      When setting QSG_INFO=1, I have

      Creating QRhi with backend OpenGL for window 0x558878401880 (wflags 0x1)
        Graphics API debug/validation layers: 0
        Debug markers: 0
        Timestamps: 0
        Prefer software device: 0
        Shader/pipeline cache collection: 1
      Created OpenGL context QSurfaceFormat(version 4.5, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 1, colorSpace QColorSpace(), profile  QSurfaceFormat::CompatibilityProfile)
      OpenGL VENDOR: Mesa RENDERER: llvmpipe (LLVM 15.0.7, 256 bits) VERSION: 4.5 (Compatibility Profile) Mesa 23.2.1-1ubuntu3.1~22.04.3
      

      Setting QT_LOGGING_RULES=qt.webengine.compositor.debug=true I was able to get the following output:

      ANGLE_OPENGL display is initialized:
        GL Renderer: ANGLE (Mesa, llvmpipe (LLVM 15.0.7 256 bits), OpenGL 4.5 (Core Profile) Mesa 23.2.1-1ubuntu3.1~22.04.3)
        0 GPU(s) detected:
          Disabled
        NVIDIA Optimus: disabled
        AMD Switchable: disabled
      ...
      QPA Platform Plugin: xcb
      Skia Graphics Context Type: GaneshGL
      Native Buffer Supported: no
      Native Skia Output Device: OpenGL
      Initializing buffer 0x63d496068b00 with SharedImage:
        Usage: Gles2Read|DisplayRead|DisplayWrite
        Pixels size: 1535x827
        Format: BGRA_8888
        Backing: GLTextureImageBacking
      Backend texture is not a Vulkan texture.
      Compositor returned null texture
      

      So it seems OpenGL on Mesa LLVMpipe is used correctly, but for some reason a Vulkan texture are expected?

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            pvarga Peter Varga
            bterrier Benjamin Terrier
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              Created:
              Updated:

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