It's not raytracing the scene. It's still using triangle meshes and rasterisation. It's just the lighting model is using a compute method. Laa-Yosh is right that this isn't really software rasterising, but we're getting closer and closer. I doubt we'll go full software any time soon as triangle meshes are still the only reasonable choice for geometry in most games, but the flexibility of GPUs means the removal of fixed function pipelines and fixed rendering. Arguably, pixel and vertex shaders are software rendering - just not as adventurous as one would hope.
Indeed you have, but I've been of that opinion myself for many a year, before joining B3D.Realistic lighting makes things look real and solid, even if unnatural. Stick a PS1 low poly, low texture model in a photorealistic renderer, it'll look like a solid piece of cardboard or something. With the right shaders, it'll look like an organic polygon thing. Stick a billion poly, perfectly sculptured, wonderfully textured object in a PS3 level renderer and it'll look like a computer game.
They're specialised processors in the same way SPUs were. They're fully programmable including branching. This fact has lead to the development of compute which is running algorithms that don't need to be graphics based. They can't get much more software based without becoming CPUs and losing their performance advantage for massively parallel workloads.
Then why didn't you mention async compute? Because it's the async compute part that's saving 5ms, not the use of compute versus graphics pipeline.
I remember a conversation where some people posted that PS4 would be able to get 1.8 TF of graphics and a load more compute work as well.
That's a silly comparison. In this workload, there was lots of spare performance for async compute. In other workloads, the GPU could be pretty saturated at 1.84 TFlops and have little room for parallel compute workloads. So where technically right (The Tomorrow People would need a 2.3 TF GCN GPU to achieve the same results without async compute as a 1.8 TF GCN GPU using async compute), it's a nonsensical number. The purpose of any optimisation is to increase efficiency - there's no value in trying to turn that into a numbers comparison other than % improvement and time saved.
