Multi-Precision Ray-Primitive Intersection for Faster Ray Tracing
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Solution Overview
Problem
Ray tracing in graphics processing is computationally expensive due to the large number of primitive intersection tests, which can be improved by reducing the computational expense through the use of reduced-precision tests before higher-precision tests.
Innovation Solution
Performing a conservative reduced-precision primitive test followed by a higher-precision test to determine actual hits, using error bounds calculation and quantized representations to reduce computational complexity and resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If higher-precision primitive intersection tests are performed for all rays, then measurement precision is improved, but computational expense increases
Solution Approach 1:
The intersection testing process is segmented into two distinct stages: a reduced-precision conservative test that quickly eliminates non-intersecting rays, followed by a higher-precision test that accurately determines intersections for remaining candidate rays. This segmentation allows the system to apply different precision levels appropriately, reducing overall computational expense while maintaining measurement precision where necessary.
Solution Approach 2:
The patent changes the precision parameter of the intersection test dynamically. Initially, a reduced-precision test is performed with relaxed accuracy requirements to quickly filter out non-intersecting rays. Then, for rays that pass the conservative test, the precision parameter is increased to perform an accurate intersection determination. This parameter change strategy optimizes the balance between computational expense and measurement precision.
2Productivity
If reduced-precision tests are used to reduce computational expense, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
A reduced-precision conservative test is performed as a preliminary action before the higher-precision intersection test. This preliminary test uses error bounds calculation to determine if a ray could possibly intersect a primitive, eliminating clearly non-intersecting rays without requiring full precision calculations. This preliminary filtering action improves productivity while the subsequent high-precision test ensures measurement precision is maintained for candidate intersections.
Solution Approach 2:
Error bounds calculation serves as an intermediary mechanism between the reduced-precision conservative test and the higher-precision intersection test. The error bounds provide a mathematical guarantee that the conservative test will not incorrectly reject valid intersections, thus maintaining measurement precision while enabling the productivity benefits of reduced-precision filtering.
3Device complexity
If conservative reduced-precision tests with error bounds are performed, then device complexity is reduced, but reliability may be affected
Solution Approach 1:
Error bounds are calculated beforehand to cushion against the reduced precision of the conservative test. These pre-calculated error bounds provide a safety margin that ensures the conservative test will not incorrectly reject valid intersections due to precision limitations. This beforehand cushioning maintains intersection test reliability while allowing the use of simpler, reduced-precision computational methods.
Data Source
AI summary
Techniques are disclosed relating to testing whether a ray intersects a graphics primitive, e.g., for ray tracing. In some embodiments, intersection circuitry performs a reduced-precision conservative intersection test and shader circuitry performs an original-precision intersection test if the intersection circuitry indicates a hit. The intersection circuitry may quantize the ray (and may quantize the primitive or may receive a quantized representation of the primitive). The intersection circuitry then determines an intersection result for the reduced-precision test based on the quantized primitive data and quantized ray data. In various embodiments, disclosed techniques may improve performance or reduce power consumption by reducing the number of original-precision intersection tests that do not result in hits.