Real-time ray tracing on coarse-grained reconfigurable processor

Ray tracing is a 3D rendering method for generating an image by simulating the path of light. It can generate high quality images, but it requires great computing power. Recent advances in ray tracing technology enable realtime ray tracing on modern desktop CPUs/GPUs. But in the current mobile environment, it is difficult because of inadequate computing power, memory bandwidth, and flexibility in mobile GPUs. In this paper, we present a mobile ray tracing system using Samsung Reconfigurable Processor (SRP). SRP architecture includes a tightly coupled very long instruction word (VLIW) engine and coarse-grained reconfigurable array (CGRA). The VLIW engine is designed for general-purpose computations, such as function invocation and branch selection, and the coarsegrained reconfigurable array is specialized for data-intensive part of the program and can be configured dynamically. We proposed iterative batch-based ray tracing algorithm for SRP, and optimized memory bandwidth with local memory and data cache. Our ray tracing system is implemented on a commercial FPGA-based prototyping system. The experimental results show that our system is suitable for the mobile ray tracing.