The metric Pixels Rendered represents the number of pixels that passed the depth-test (both Z-buffer and Stencil if enabled). If the depth-test was disable Pixel Rendered counts all the pixels which passed through from previous pipeline stage.
Pixels which passed the depth-test may not necessarily appear in the render target, which could occur if the color buffer write mask is set to 0.
- If you render a quad with 8×8 pixels size, located entirely within the viewing frustum and all the pixels passed depth test Pixel Rendered is 64.
If you render a quad with 8×8 pixels, and the quad is located entirely within the viewing frustum, and half of the pixels are rejected by depth tests or other stages of the graphics pipeline, the metric Pixel Rendered is 32.
A high number of rendered pixels results in a high number of pixel shader executions, and thus requires more rendering time. To keep the number of rendered pixels as low as possible, optimize the rendering order to maximize Early-Z benefit or use Z-only pass if possible.
To find areas with high depth complexity, use the Overdraw option in the Intel® GPA Frame Analyzer.