Graphics Processing Circuit Shadow Plane Illumination
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Solution Overview
Problem
Conventional methods for determining pixel luminance in graphics processing suffer from aliasing artifacts and self-shadowing due to fixed straight-line distance calculations, leading to inaccurate luminance values and distortions in rendered images.
Innovation Solution
A graphics processing circuit that computes luminance values by defining a plane containing the pixel of interest and using a shadow map to determine distances from the light source at multiple locations on this plane, eliminating the need for constant straight-line distance calculations and reducing self-shadowing and aliasing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fixed straight-line distance calculations are used for luminance determination, then the calculation is simple and fast, but self-shadowing and aliasing artifacts occur leading to inaccurate luminance values
Solution Approach 1:
The patent transitions from one-dimensional straight-line distance calculations to two-dimensional planar distance calculations. By defining a plane containing the pixel of interest and computing distances along this plane rather than through fixed straight lines, the system eliminates self-shadowing artifacts while maintaining computational feasibility. This dimensional change allows accurate luminance determination without the complexity of full ray-tracing methods.
2Measurement precision
If multiple rays are tested from positions near the pixel of interest to determine visibility, then smoother transitions between illuminated and shadowed pixels are achieved, but computational cost increases significantly
Solution Approach 1:
The patent extracts the essential information needed for luminance calculation by defining a plane containing the pixel of interest and computing distances only along this plane. This extraction approach eliminates the need to test multiple rays from various positions, significantly reducing computational cost while maintaining accurate luminance determination through planar geometry.
3Productivity
If constant straight-line distance is used for luminance calculation, then the calculation is efficient, but pixels below the plane of the pixel of interest are incorrectly included as shadowed pixels
Solution Approach 1:
The patent applies local quality by restricting distance calculations to positions on the specific plane containing the pixel of interest. This localized approach ensures that only relevant pixels (those on the same plane) are considered in luminance calculations, preventing incorrect inclusion of pixels below the plane while maintaining calculation efficiency through planar geometry rather than full 3D ray-tracing.
Data Source
AI summary
A graphics processing circuit includes a pixel shader operative to provide pixel color information in response to image data representing a scene to be rendered; a texture circuit, coupled to the pixel shader, operative to determine a luminance value to be applied to a pixel of interest based on the luminance values of the pixels that define a plane including the pixel of interest; and a render back end circuit, coupled to the texture circuit, operative to compute the luminance values from a shadow map that specifies the distance from the light source of the nearest object at a plurality of locations. A pixel illumination method includes receiving color information for a pixel to be rendered, defining a plane containing at least one pixel of interest, the plane including a plurality of planar values; comparing the plurality of planar values to a corresponding set of distance values; determining a luminance value for the at least one pixel of interest; and applying the luminance value to the at least one pixel of interest.