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Best approach for fully dynamic shadows on latest hardware?

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I would like to know what the visually best approach would be for dynamic directional+omni shadows on the current hardware (ps 3+)? Stencil, Mapping, or?

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Stencil shadows and shadow maps are the same thing :). What method you use depends on the number of shadows that are going to be cast and how complex your scenes are.
Shadow Volumes are the best looking visually, but are very dependent on fillrate, the speed of the hardware and the complexity of the scene, and are the slowest (usually) of the various methods.
Shadow maps are (again usually) much faster, but suffer from artifacts as they are a pixel based technique. Theres an article that was featured here not long ago that gave a technique for reducing these artifacts and producing a fake soft shadow effect though.

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hm the only thing both have in common is that they both generate shadows.

shadowmaps all the way. performance is much more stable than shadow volumes, and it scales about the same way your ordinary renderer scales. you can have alpha-masked objects (like trees with leafes etc), and it's really _MUCH_ cheaper.

a tree throwing a shadow volume... ouch.

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Realtime raytracing in the pixel shader [wink]

It depends on your geometry, and where your current bottlenecks are. davepermen rightly 'ouches' at the thought of a tree throwing a shadow volume, but if you're doing very little else with the vertex processor, it might not be too bad. As always, profile profile profile....

That said I'd usually recommend shadow maps as well. Very versatile, and can be easily integrated into an existing projected texture system. There's also the advantage that they're supported on older NVidia hardware, too (though on ATI cards you're SOL because you need floating-point textures).

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Though note that for omni-directional lighting you need to use some extension of the Shadow Mapping technique such as cube or dual paraboloid mapping (the standard method only works with directional lights). Check out this paper for more info.

Shadow Volumes on the other hand handle point lights automatically and since you ask for "the visually best approach", that would be Shadow Volumes. Shadow Maps have sampling problems and aliasing artifacts inherent in the results caused by low-resolution shadow maps, quantisation and perspective projection. Though there are ofcourse several ways of reducing such problems.

[Edited by - gazsux on March 1, 2005 9:29:03 PM]

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