cubemapped depth texture

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2 comments, last by JSoftware 19 years, 10 months ago
am i able to make a cubemapped depthtexture for shadow mapping purposes? if yes): how the heck?!? if no): thanks for your time then i would have written something here but i just forgot.. regards jeppe
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Depends on your API and how you encode the depth texture values. Let''s say it like this: on GeForce FX or Radeon 9x00 class hardware, yes, it''s definitely possible by using pixel shaders.

On older hardware, it''s difficult (shadow mapping isn''t natively supported for cubemaps, because of the conflicting usage of the third texture coordinate), but not impossible using lots of tricks (and probably reduced precision).

If you''re trying to shadow map point light sources, dual paraboloid mapping can be a viable alternative to cubemapping.
i''ve tried to find something on dual parabolid ( or however you spell it) but the only info i found had no source included in it..

can you explain how it''s working?
quote:Original post by JSoftware
i''ve tried to find something on dual parabolid ( or however you spell it) but the only info i found had no source included in it..


Huh ? A simple Google search returned over 900 results, the first link is to a demo from Delphi3D (with source), the second one the well known paper from Stefan Brabec... I would suggest taking a look at those two.

quote:Original post by JSoftware
can you explain how it''s working?

Basically you have two shadow maps, in the form of a compressed elipse around the light. A special wide angle projection is used to render the complete environment onto them. That environment is reindexed later on, two shadow comparisons calculated, and an alpha function is used to select the appropriate result. But read Stefan''s paper, everything is detailed in there.

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