An AMD patent may have just shown the company's hand when it comes to its interpretation of raytracing implementation on graphics cards. The patent, titled "Texture Processor Based Ray Tracing Acceleration Method and System", describes a hybrid, software-hardware approach to raytracing. AMD says this approach improves upon solely hardware-based solutions:

"The hybrid approach (doing fixed function acceleration for a single node of the bounded volume hierarchy (BVH) tree and using a shader unit to schedule the processing) addresses the issues with solely hardware based and/or solely software based solutions. Flexibility is preserved since the shader unit can still control the overall calculation and can bypass the fixed function hardware where needed and still get the performance advantage of the fixed function hardware. In addition, by utilizing the texture processor infrastructure, large buffers for ray storage and BVH caching are eliminated that are typically required in a hardware raytracing solution as the existing vector general purpose register (VGPRs) and texture cache can be used in its place, which substantially saves area and complexity of the hardware solution."