Scene Graph: A Different Approach to Graphics in Qt
summary
A small scene graph replaces QPainter/GraphicsView for QML and renders with OpenGL ES 2.0, reorders draw calls to cut redundant state changes and avoids overdraw (example shows about 20% less wasted pixels). It uses per-effect FBOs (demo uses 16 FBOs), nested subgraphs, stencil clipping and a vertex/fragment ShaderEffectItem with automatic uniform binding. Demos run on an old Mac at ~15% CPU, gradients on N900 use textured approach to save ~5 ms, and the prototype works as advertised.
AI-written summary · about
chapters (12)
- 0:00Introduction to Qt Graphics
- 2:08Current Graphics Stack
- 5:50Limitations of Painters
- 10:43Optimizing Overdraw
- 13:16State Changes and Ordering
- 17:08Qt Scene Graph Project
- 21:11Scene Graph Structure
- 24:27Adaptation and Effects
- 26:59QML Shader Demonstration
- 33:38Nested Rendering Techniques
- 38:34Q&A: Widgets and Performance
- 47:23Q&A: Threading and APIs
related talks
01h 02mUsing Qt Quick and the new Qt graphics stack, Scene Graph
46mWhat's new in QtQuick 2.0
48mBuilding Desktop and Embedded Uis with Qt 3D
55mIntegrating OpenGL with Qt Quick 2 applications
48mBuilding Desktop and Embedded Uis with Qt 3D
38mMy journey with WebGL
52mPimp your UI - Using effects, transitions, etc.
40mImplementing custom fragment shaders