shadow mapping or deferred shading and volume shadows

JPulham · Post by **JPulham** » Thu Jun 07, 2007 11:21 am

I have a game that I want to run on old(er) hardware (OpenGL and 1-2GHz processor

) but I'm not sure how I should add shadows to my characters.

I'm torn between Shadow mapping and Deferred shading. Deferred shading looks good but how easy could the shadow volumes in irrlicht be modified to use it. Shadow-mapping has the problem of one pass per light and blocky aliasing effects (even though there are ways to combat this)

now over to you... how should I shadow my levels?

BlindSide · Post by **BlindSide** » Thu Jun 07, 2007 12:43 pm

I am planning this too and looking at Shadow mapping as it seems to be the most common and best for performance. Also the shadows are automatically a little blurred because of the low resolution of shadows..

Here is a link to a good ShaderX chapter: http://ati.amd.com/developer/shaderx/Sh ... rusion.pdf

JPulham · Post by **JPulham** » Thu Jun 07, 2007 2:16 pm

shadow mapping does look ok... but I thought that deferred shading might be quicker (could be wrong though

)
One thing I haven't considered is that the shadow map only needs to be applied to your gun and 15 other players, not a intensive as a full level

Saturn · Post by **Saturn** » Thu Jun 07, 2007 2:39 pm

Deferred Shading is only faster than "immediate shading" for complex scenes with many lights and only really an option, when you have multiple render targets available, which older cards that you want to address don't support. Else you have to render the scene with multiple passes, which will make rendering even slower. So realistically Deferred Shading is not an option.