Hybrid raytraced shadows and reflections

Unless you’ve been hidden in a cave the past few months, doing your rendering with finger painting, you might have noticed that raytracing is in fashion again with both Microsoft and Apple providing official DirectX (DXR) and Metal support for it.

Of course, I was curious to try it but not having access to a DXR capable machine, I decided to extend my toy engine to add support for it using plain computer shaders instead.

I opted for a hybrid approach that combines rasterisation, for first-hit determination, with raytracing for secondary rays, for shadows/reflection/ambient occlusion etc. This approach is quite flexible as it allows us to mix and match techniques as needed, for example we can perform classic deferred shading adding raytraced ambient occlusion on top or combine raytraced reflections will screen space ambient occlusion, based on our rendering budget. Imagination has already done a lot of work on hybrid rendering, presenting a GPU which supports it in 2014. Continue reading “Hybrid raytraced shadows and reflections”

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Hybrid raytraced shadows and reflections