Shadow volumes definitely dead?

Vilem_Otte 117 Jan 03, 2014 at 15:15 shadows

Honestly I haven’t seen any game with shadow volume implementations for good few years, is the tech really dead? Because from my point of view, they are much more accurate than shadow mapping and also doesn’t suffer from lots of shadow mapping problems (on the other hand, they suffer from fillrate and complex geometry - although that isn’t a problem since the age of geometry shaders).

Is anyone of you working with shadow volume tech these days?

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TheNut 179 Jan 03, 2014 at 15:49

I haven’t used shadow volumes in a long time (since the widespread of shader support in consumer hardware). Shadow casting is one of those problems that currently doesn’t have an ideal technical implementation yet. Both solutions have their pros and cons, but shadow maps give you much more bang for your buck. Easier to implement, smooth looking penumbras, generally lower performance impact (but this can vary on shadow map complexity too), and independent of scene/geometry complexity.

Personally, I can’t wait until real-time ray tracing becomes more of a reality. Working with lights and shadows in a ray tracer is vastly more intuitive than messing around with hack’ish solutions.

Vilem_Otte 117 Jan 04, 2014 at 20:48

True, well I still have somewhere an implementation of single-pass depth-fail shadow volumes using geometry shader. I even tried plausible shadows using penumbra wedges and visibility buffer (but meh, for complex models this introduces tons of issues, yet yields correct penumbra shadows).

As for shadow mapping - it isn’t possible to achieve correct penumbra shadows with them. And for most solutions they use jittering (which I personally HATE, noise is just pure evil on screen, and players hate it) - so I am using quite heavy filter that doesn’t result in noisy result.

Ray traced shadows are good (I work with ray tracers a lot), doing realtime ray tracing in whitted style isn’t a problem on good gpu. Path tracing is, it is just noisy. Don’t get me wrong, there are ppl with good results (Jacco Bikker with his Brigade for example - nothing against Brigade, it is awesome piece of technology, it’s not just suited for games yet), but it is still noisy and it will still be noisy within next years. I think thats the main problem with path tracing for now, the noise is too huge compared to real world (there is noise too in your vision, but barely visible), I think we need some improvement of current algorithms. Of course, for static frames or movies, it is awesome.

rouncer 103 Jan 19, 2014 at 21:42

man, i buy top of the market and just raytrace em, quick as reflections, quicker if your doing refractions too.