Overdraw Visualization

Use this override mode to visualize the overall complexity of your scene, highlighting potential areas to investigate for optimization. If a scene renders only a few objects, the amount of overdraw is usually low and no further optimization is required. If a scene has many overlapping objects, or objects with semitransparent textures (such as smoke, fog, or water), this typically results in a high load on the graphics card and therefore lower frame rates.

The Overdraw Visualization mode fills the frame buffer with a brightness value according to the numbers of times each pixel is drawn. The brightness of a pixel indicates the number of times each pixel was “touched” by a draw call or clear call. The darker a pixel, the fewer number of times it has been overdrawn; conversely, the lighter a pixel, the more times it was overdrawn. Bright areas of the screen may provide optimization opportunities such as culling primitives prior to rendering them, altering the draw order (so that z-buffer tests will reject many primitives prior to rendering them with an expensive pixel shader), or using other level-of-detail optimizations that simplify the complexity of the scene.

If the overdraw value in one or more areas of the scene is high, use the Intel® GPA Frame Analyzer with the Pixel History feature with overdraw mode enabled – these will help you understand which ergs are being rendered into each pixel and help pinpoint optimization opportunities.

 
                              Normal Picture                                                                            Overdraw Visualization

See Also

Override Modes Overview
Disable all overrides
Null Hardware
Disable Draw Calls
Wireframe
2×2 Texture
Simple Pixel Shader
1×1 Scissor Rect
Disable Texture Filtering
Disable Z-Test
Disable Z-Write
Cull None
Cull Clockwise
Cull Counter-Clockwise
Disable Alpha Blending
Disable Alpha Test
FPS Limit

Overdraw Visualization