AMD already applied for a patent at the end of 2017 for a technique for real-time ray tracing that combines software and hardware. The manufacturer has not yet announced GPUs that offer hardware acceleration specifically for ray tracing calculations.
The patent filed by AMD in December 2017 with the US Patent and Trademark Office describes a hybrid approach to enable real-time ray tracing under the heading “Texture processor based ray tracing accelerator method and system.” Tom’s Hardware, among others, writes about the patent.
The combination of a texture processor with shader software provides flexibility without the drawbacks of a purely hardware or software approach, according to the patent application. “The flexibility is preserved because the shader unit can manage the overall computations, bypass the fixed function hardware where necessary, and still leverage the performance of that hardware,” according to a passage from the application.
According to AMD, the described approach also does not require a large buffer for the storage of ray information and caching, so that the hardware needs to be less complex than with a purely hardware method for real-time ray tracing.
It is not known to what extent AMD applies the described method in its plans for ray tracing. The company has not yet announced much about those plans. Unlike Nvidia’s RTX cards, the upcoming RX 5700 cards with Navi GPUs do not yet have hardware support for ray tracing, but subsequent Navi chips based on an improved RDNA architecture do. This concerns limited support for light effects. The Xbox Project Scarlett will get a Navi GPU based on this next-gen RDNA architecture. The PlayStation 5 only talks about ‘Navi’ and not about next-gen. At the time of the announcement of Navi, AMD seemed to see more use of servers for full real-time ray tracing.
You can read more about ray tracing in the RTX Turing background article Ray tracing and neural networks in GPUs.