Ray Tracing Shader API for Non-Recursive Buffer-Based Rendering
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Solution Overview
Problem
Conventional recursive ray tracing methods require significant memory and computational resources due to the need to maintain and store ray state, leading to inefficiencies and stack-based processing that hinder performance.
Innovation Solution
A non-recursive ray tracing approach using a programming interface that allows shaders to emit rays and contribute directly to a buffer without waiting for downstream results, utilizing a programming semantic that includes an 'emit ray' and 'contribute' call to manage ray tracing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If recursive ray tracing is used to maintain complete ray state for downstream processing, then rendering accuracy is improved, but memory usage and computational overhead increase significantly
Solution Approach 1:
The patent applies preliminary action by performing ray intersection testing and identifying intersected primitives before complete downstream processing. Shaders execute immediately with available information, contributing results to buffers without waiting for the entire ray tree to complete. This eliminates the need to store complete ray state for all downstream operations while maintaining rendering accuracy through immediate buffer contributions.
Solution Approach 2:
The patent segments the ray tracing process into independent shader execution units that operate autonomously. Each shader processes its specific primitive intersection and contributes results to buffers independently, rather than maintaining a unified ray state across the entire recursive tree. This segmentation allows memory to be released after each shader completes its contribution, significantly reducing overall memory usage.
2Measurement precision
If recursive ray tracing maintains complete ray state for downstream processing, then rendering accuracy is improved, but processing speed decreases due to stack-based operations
Solution Approach 1:
The patent performs preliminary ray intersection testing and primitive identification before shader execution, allowing shaders to immediately process and contribute results without waiting for downstream ray tree completion. This eliminates stack-based waiting periods and enables parallel processing of multiple rays, significantly improving processing speed while maintaining accuracy through immediate buffer contributions.
Solution Approach 2:
The patent enables continuous useful action by allowing shaders to execute and contribute results as soon as their primitive intersections are identified, without pausing for downstream processing. Multiple shaders can operate concurrently and continuously write to buffers, eliminating the idle waiting periods inherent in recursive stack-based approaches and maximizing processor utilization.
3Ease of operation
If recursive ray tracing is used to process rays in order with stack-based state storage, then shader execution control is simplified, but device complexity increases due to stack management requirements
Solution Approach 1:
The patent extracts the ray state maintenance function from the shader execution control mechanism. Instead of using stack-based state storage within the recursive control flow, the patent separates shader execution into independent units that read intersection data from buffers and write results to buffers, eliminating the need for complex stack management while maintaining execution control through buffer-based data flow.
4Quantity of substance
If non-recursive ray tracing with immediate buffer contribution is used, then memory usage and processing speed are improved, but shader coordination complexity increases
Solution Approach 1:
The patent introduces buffers as intermediary data structures that mediate between independent shader executions. Shaders write intersection results and lighting calculations to buffers, and subsequent shaders read from these buffers to continue processing. This buffer-mediated coordination simplifies the interaction between non-recursive shaders compared to direct shader-to-shader communication, reducing coordination complexity while enabling parallel execution and low memory usage.
Data Source
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AI summary
A system for performing ray-tracing based rendering comprising an intersection testing unit operable to identify an intersection between a ray and a primitive in a 3-D scene being rendered. The system also comprises a processor capable of being configured with shader code to be executed; and a controller operable to determine whether an identified portion of shader code, associated with the primitive, is to begin execution on the processor, responsive to the intersection between the ray and the primitive, based on an estimated number of rays that would be emitted by the portion of shader code during execution and a status of a memory that will store data defining the emitted rays.