Texel Addressing Mode for Texture Filtering Artifacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current texture filtering methods in graphics processing, particularly with tiled resources and sparse textures, result in visually distracting artifacts due to the use of unmapped tiles and incorrect interpolation near the edges of the texture domain, leading to issues with anisotropic filtering and texture sampling.
Innovation Solution
Implementing a texel addressing mode that places texels at the corners of the sampling region, reducing the sampling region by one texel, and using valid texels within the domain for filtering operations, while discarding out-of-bounds sample taps to ensure smooth anisotropic sampling across multiple textures and at the edges of null tiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If linear interpolation is used near the border of the texture domain, then filtering operations can access texels outside the valid domain, but this results in incorrect color values and visual artifacts
Solution Approach 1:
The patent extracts and removes the problematic out-of-bounds texel accesses from the filtering operation. By identifying that only the outermost half-texel-wide region causes issues, the solution discards sample taps that would access invalid texels, keeping only the valid portion of the filtering operation.
Solution Approach 2:
The patent applies different handling to different regions of the texture domain. Valid texels within the domain are accessed normally for filtering, while out-of-bounds texels in the outermost half-texel-wide region are discarded. This local differentiation ensures correct color values are used where valid data exists while avoiding artifacts at the boundaries.
2Adaptability or versatility
If wrapping modes are applied to out-of-bounds texels, then the texture can be sampled continuously across edges, but this produces incorrect colors and visual artifacts
Solution Approach 1:
The patent removes the wrapping operation for out-of-bounds texels entirely. Instead of applying wrap modes that produce incorrect colors, the solution extracts and discards the problematic sample taps that would access wrapped texels, preventing the color accuracy issue while maintaining valid sampling within the texture domain.
3Reliability
If null tile fallback is used for unmapped tiles, then filtering can proceed without errors, but this causes images to fade to black and produces visual artifacts
Solution Approach 1:
The patent extracts and removes the null tile fallback mechanism that causes visual artifacts. By discarding sample taps that would access unmapped tiles, the solution eliminates the harmful fallback behavior that produces black fading and artifacts, while maintaining reliable filtering operations that only use valid mapped tiles.
Solution Approach 2:
The patent applies different handling to mapped and unmapped tiles. For mapped tiles, normal filtering operations proceed reliably. For unmapped tiles in the outermost half-texel-wide region, the solution discards sample taps rather than applying null tile fallback, preventing visual artifacts while maintaining operational reliability for valid regions.
4Productivity
If the sampling region includes the outermost half texel-wide region, then linear interpolation can access more texels, but this creates a half texel-wide region of incorrectly interpolated color
Solution Approach 1:
The patent extracts and removes the outermost half-texel-wide region from the sampling operation. By discarding sample taps that would access texels in this problematic region, the solution eliminates the incorrectly interpolated color while maintaining productive sampling operations for the valid inner region.
Data Source
AI summary
The adverse affects of using out-of-bounds texels for bilateral interpolation may be reduced by redefining the valid texel domain as having four corners defined at the centers of four corner texels. As a result, the texels around the periphery of the valid texture domain are partial texels, with the corner texels being one quarter of a texel and the edges being half of a texel.