Potentially Occluded Rasterization Shading Fidelity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing computer graphics systems face inefficiencies in rendering images due to overdraw, where closer objects overwrite pixels of more distant objects, leading to wasteful processing and potential artifacts.
Innovation Solution
The method involves pre-populating a potentially occluded depth map in a GPU for the current frame using depth data from previous frames, low resolution depth pre-passes, or rasterizing occlusion geometry. This allows the GPU to determine at the rasterization stage whether a portion of a triangle is likely occluded and reduce the fidelity of shading accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a depth pre-pass is used to eliminate overdraw, then overdraw is avoided, but every object must be processed twice which increases processing expense
Solution Approach 1:
The patent applies partial action by performing depth testing only on a subset of pixels (those potentially occluded) rather than all pixels. The system identifies potentially occluded pixels using a coarse depth buffer and applies full depth testing only to those specific pixels, avoiding the need to process every object twice while still eliminating overdraw for the relevant pixels.
2Loss of energy
If software occlusion render is used to test bounding volumes, then occluded objects can be prevented from rendering, but partially occluded objects are still rendered fully resulting in overdrawn pixels
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different pixel regions within the same object. Instead of rendering entire objects uniformly, the system identifies specifically which pixels are potentially occluded and applies reduced fidelity shading only to those local regions, while maintaining full fidelity for visible pixels.
3Measurement precision
If rendering is performed at full fidelity for all pixels, then image quality is maintained, but processing overhead increases due to shading every pixel including potentially occluded ones
Solution Approach 1:
The patent applies dynamics by making the shading fidelity adaptive rather than static. The system dynamically adjusts the level of shading detail based on the occlusion status of each pixel, using full fidelity shading for visible pixels and reduced fidelity for potentially occluded pixels, optimizing processing based on actual scene conditions.
Data Source
AI summary
Examples described herein relate to rendering an image using a reduced fidelity of shading for portions of a triangle that are potentially occluded by other objects. A computer device may pre-populate a potentially occluded depth map in a graphics processing unit (GPU) for a current frame based on depth data of a previous frame, a low resolution depth pre-pass, or a rasterizing occlusion geometry. The GPU may determine, at a rasterization stage, that a depth of a portion of a triangle being processed is further than a depth of a corresponding tile in the potentially occluded depth map. The GPU may decrease a fidelity of shading applied to at least the portion of the triangle in comparison to a specified fidelity for the triangle in response to determining that the depth of the portion of the triangle is further than the depth of the corresponding tile.