We explore a first proof-of-concept example of creatively using the Turing generation's hardware ray tracing cores to solve a problem other than classical ray tracing, specifically, point location in unstructured tetrahedral meshes. Starting with a CUDA reference method, we describe and evaluate three different approaches to reformulate this problem in a manner that allows it to be mapped to these new hardware units. Each variant replaces the simpler problem of point queries with the more complex one of ray queries; however, thanks to hardware acceleration, these approaches are actually faster than the reference method.
Compressed wide bounding volume hierarchies can significantly improve the performance of incoherent ray traversal, through a smaller working set of inner nodes and therefore a higher cache hit rate. While inner nodes in the hierarchy can be compressed, the size of the working set for a full traversal stack remains a significant overhead. In this paper we introduce an algorithm for wide bounding volume hierarchy (BVH) traversal that uses a short stack of just a few entries. This stack can be fully stored in scarce on-chip memory, which is especially important for GPUs and dedicated ray tracing hardware implementations. Our approach in particular generalizes the restart trail algorithm for binary BVHs to BVHs of arbitrary widths. Applying our algorithm to wide BVHs, we demonstrate that the number of traversal steps with just five stack entries is close to that of a full traversal stack. We also propose an extension to efficiently cull leaf nodes when a closer intersection has been found, which reduces ray primitive intersections by up to 14%.
Mesh colors provide an effective alternative to standard texture mapping. They significantly simplify the asset production pipeline by removing the need for defining a mapping and eliminate rendering artifacts due to seams. This paper addresses the problem that using mesh colors for real-time rendering has not been practical, due to the absence of hardware support. We show that it is possible to provide full hardware texture filtering support for mesh colors with minimal changes to existing GPUs by introducing a hardware-friendly representation for mesh colors that we call patch textures. We discuss the hardware modifications needed for storing and filtering patch textures.
Data movement, particularly access to the main memory, has been the bottleneck of most computing problems. Ray tracing is no exception. We propose an unconventional solution that combines a ray ordering scheme that minimizes access to the scene data with a large on-chip buffer acting as near-compute storage that is spread over multiple chips. We demonstrate the effectiveness of our approach by introducing Mach-RT (Many chip - Ray Tracing), a new hardware architecture for accelerating ray tracing. Extending the concept of dual streaming, we optimize the main memory accesses to a level that allows the same memory system to service multiple processor chips at the same time. While a multiple chip solution might seem to imply increased energy consumption as well, because of the reduced memory traffic we are able to demonstrate, performance increases while maintaining reasonable energy usage compared to academic and commercial architectures. This article extends our previous work E. Vasiou, K. Shkurko, E. Brunvand, and C. Yuksel, "Mach-RT: A many chip architecture for high-performance ray tracing," in Proc. High-Perform. Graph. Conf., 2019 with design space exploration of the L3 cache size, more detailed evaluation of energy and memory performance, a discussion of energy delay product, and a brief exploration of boards with 16 chips. We also introduce new treelet enqueueing logic for the predictive scheduler.
Although interactive ray tracing has been around since the late 1990s, real-time frame rates had so far only been feasible for low and mid-size screen resolutions. Recent developments in GPU hardware, that specifically accelerate ray tracing, make it possible for the first time to target head-mounted displays (HMDs), which require constant high frame rates as well as high resolution images for each eye. This allows for utilizing ray tracing algorithms in novel virtual reality scenarios, which are impractical to do with rasterization. In this short paper we present our experiences of applying real-time ray tracing to the problem of detecting cosmetic defects in sheet metal stamping simulations by creating a virtual light cage.
