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  1. Qt
  2. QTBUG-29264

Rendering stalls in glyph cache

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P3: Somewhat important
    • Resolution: Done
    • Affects Version/s: 5.0.0
    • Fix Version/s: 5.5.1
    • Component/s: Quick: SceneGraph
    • Labels:
      None

      Description

      I am observing non-smooth rendering with an AMD Z430 GPU. The long frame times appear to occur due to QSGDefaultDistanceFieldGlyphCache::storeGlyphs() (in particular the call to resizeTexture() appears to be slow).

      Changing QSGDefaultDistanceFieldGlyphCache::useWorkaroundBrokenFBOReadback() to return true greatly improves the situation. However, there are still significant missed frames.

      Adding a QElapsedTimer to storeGlyphs, and flicking a list with text, the following times are initially reported (in ms):
      178, 46, 72, 66, 69
      with the workaround enabled, the times are (in ms):
      21, 22, 30, 22, 21

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              Assignee:
              ylopes Yoann Lopes
              Reporter:
              mbrasser Michael Brasser
              Votes:
              1 Vote for this issue
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                Dates

                Created:
                Updated:
                Resolved:

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