Graphics Processing Shadow Rendering via World-Space Sub-Volume Partitioning
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Solution Overview
Problem
Existing methods for rendering images in graphics processing systems do not efficiently account for shadow effects, particularly when dealing with volumetric effects like smoke or moving particles, as they are often tied to screen space and lack advanced preprocessing for shadow geometry sorting.
Innovation Solution
The method involves partitioning the 3D world-space volume into sub-volumes to determine geometry that can cast shadows, allowing for per-vertex and per-sample visibility parameters to be derived, facilitating more efficient shadow rendering by preprocessing shadow geometry and light source visibility parameters before transformation to screen space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow rendering is performed using traditional screen space methods, then the rendering process is simpler, but the accuracy and efficiency for volumetric effects like smoke and moving particles deteriorates
Solution Approach 1:
The patent segments the 3D world space into multiple sub-volumes (e.g., using a bounding volume hierarchy or spatial partitioning data structure). This allows the system to process shadow casting geometry and light source visibility independently for each sub-volume, improving accuracy for volumetric effects while managing computational complexity through hierarchical processing.
Solution Approach 2:
The patent performs preliminary actions by pre-determining which geometry can cast shadows in each sub-volume and pre-calculating light source visibility parameters before the main rendering transformation to screen space. This preprocessing step enables more accurate shadow rendering for volumetric effects without increasing the complexity of the final rendering pipeline.
2Manufacturing precision
If per-vertex and per-sample visibility parameters are calculated for all geometry, then shadow rendering accuracy improves, but computational overhead increases
Solution Approach 1:
The patent applies local quality by calculating visibility parameters selectively for each sub-volume based on its specific content and requirements. Not all geometry in the scene requires the same level of processing - the system determines locally which sub-volumes need detailed per-vertex and per-sample visibility calculations, thereby reducing overall computational overhead while maintaining accuracy where needed.
Solution Approach 2:
By segmenting the scene into sub-volumes, the system can process visibility parameters for only the relevant portions of the scene, rather than uniformly processing all geometry. This segmentation enables the system to maintain high accuracy for critical areas while reducing computational overhead for less important regions.
3Adaptability or versatility
If shadow geometry is processed in screen space, then the rendering pipeline is simpler, but the handling of moving objects and volumetric effects deteriorates
Solution Approach 1:
The patent transitions from traditional 2D screen space processing to 3D world space sub-volume processing. By performing shadow geometry determination and visibility parameter calculation in the 3D world space before transformation to screen space, the system gains superior handling of moving objects and volumetric effects. The complexity is managed through hierarchical sub-volume processing rather than uniform 3D processing of the entire scene.
Data Source
AI summary
When rendering a scene for output that includes a light source that could cast shadows in a graphics processing system, the world-space volume for the scene to be rendered is first partitioned into a plurality of sub-volumes, and then a set of geometry to be processed for the scene that could cast a shadow from a light source to be considered for the scene in the sub-volume is determined for any sub-volume that is lit by a light source. The determined sets of geometry for the sub-volumes are then used to determine light source visibility parameters for output samples, such as vertex positions and/or screen space sampling positions, for the scene. The determined light source visibility parameter for an output sample is then used to modulate the effect of the light source at the output sample when rendering an output version of the output sample.