Real-time generation of kd-trees for ray tracing using DirectX 11

Abstract: Context. Ray tracing has always been a simple but effective way to create a photorealistic scene but at a greater cost when expanding the scene. Recent improvements in GPU and CPU hardware have made ray tracing faster, making more complex scenes possible with the same amount of time needed to process the scene. Despite the improvements in hardware ray tracing is still rarely run at a interactive speed. Objectives. The aim of this experiment was to implement a new kdtree generation algorithm using DirectX 11 compute shaders. Methods. The implementation created during the experiment was tested using two platforms and five scenarios where the generation time for the kd-tree was measured in milliseconds. The results where compared to a sequential implementation running on the CPU. Results. In the end the kd-tree generation algorithm implemented did not run within our definition of real-time. Comparing the generation times from the implementations shows that there is a speedup for the GPU implementation compared to our CPU implementation, it also shows linear scaling for the generation time as the number of triangles in the scene increase. Conclusions. Noticeable limitations encountered during the experiment was that the handling of dynamic structures and sorting of arrays are limited which forced us to use less memory efficient solutions.