Is raytracing less "expensive" than planar reflections?

[Pottuvoi]

@Manoel.Neto

Basically, you have a representation of the entire scene on the GPU at all times. If you think about it, that is already the case, since shaders, vertex buffers, and textures are all on GPU memory anyway. For RT you add the locations of the meshes and their bounding boxes, and which shaders they are using, which are executed when the rays hit a triangle.

This means many view-based optimization tricks used during rasterization like deferred shading or clustered forward lighting don’t apply during raytracing so new tricks need to be developed to optimize that.

Shading certainly will be big challenge, especially if there is need for accurate materials and lights to be dynamic.

As for optimizations using ray-tracing doesn’t really mean that everything must be correct and identical in reflections.
I’m quite excited to see how developers will start to exploit ray tracing hardware by using them with all sorts of distance cubemaps and light probes. (IE. True parallax corrected cubemaps with characters rendered within.)