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  1. Qt
  2. QTBUG-69985

Scene3D (and Studio3D) needs a way to determine if the Qt 3D scene changes

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    Description

      The way Scene3D (and all similar solutions like Studio3D or even the upcoming future Studio3DEngine+Layer3D combo) works is highly not ideal for 3D scenes that are not constantly changing.

      Marking the node as dirty and scheduling a Quick re-render by calling QQuickWindow::update() on each and every frame (this is hooked up to QQuickWindow::beforeRendering) is wasteful (performance, power) and is not acceptable to some customers. Qt Quick itself does not have this problem: if nothing changes in the Qt Quick scene (e.g. all animations stop) the render loop will not render anything.

      So Scene3DRenderer::render() (and all similar solutions in Studio3D and elsewhere) would need a way to tell if rendering needs to be done:

      if (renderAspectPrivate->needsRender()) {
    // ... set up fbo, call renderSynchronous, etc.
    node->markDirty(DirtyMaterial);
    m_window->update();
}
// else do nothing, no dirty, no update

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          relates to

          User Story - Created by Jira Software - do not edit or delete. Issue type for a user story. QT3DS-2981 Support customer project B

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-72923 Scene3D does not stop processing even when visible property is set to false

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Suggestion - Public suggestions QTBUG-70035 Qt 3D renderer design not suitable for proper Qt Quick integration

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Open

          User Story - Created by Jira Software - do not edit or delete. Issue type for a user story. QT3DS-660 Qt 3D bugs and features required for Runtime 2

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Withdrawn
          For Gerrit Dashboard: QTBUG-69985
          # Subject Branch Project Status CR V
          259043,11 Scene3D: Revise render loop and synchronization dev qt/qt3d Status: MERGED +2 0

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              zakalawe James Turner
              lagocs Laszlo Agocs
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                Updated:
                Resolved:

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