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Shadows: In Need Of Resources

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Well, I've been tinkering with lights... and I realized that the only way I'm going to get the effect that I need is if I do real time shadows. So I was wondering if there are any articles out there that may help me in this general area. I don't want anything about Static Shadows or Projective Shadows, because I need the shadow to be able to cast its self onto another portion of the source (different polygons, same shape though). I've read into Stenciled Shadows... And I have a funny feeling that is what I'm going to be using in the end (unless something better comes up). But I'm still insearch of more methods. Thanks again! §tay |{ewl, pDK [EDIT] To clarify a few things... I'm not really looking for "Put this code here" resources (if I wanted that, I have NeHe... Which I have read his Shadow Tutorial already). I'm really looking for new and improved methods. To give you a general idea on what I'm working with: Its for a terrain demo... but I really don’t want to use Static shadows because I'm recreating a Sun Rise/Set. I hope that will stop some flame mail. [edited by - pDK on August 17, 2002 3:37:33 AM] [edited by - pDK on August 17, 2002 3:38:39 AM]

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There are some excellent resources about all kinds of shadowing algorithms at nVidia's developer site. Most are not nVidia specific, or can be easily adapted to non-nVidia hardware.

Basically, you have the choice between stenciled shadow volumes or shadow maps, if you want full realtime shadows. Both have advantages and drawbacks. Stencil shadows are very easy to render, are very sharp and generally good quality. But they take up a lot of fillrate, and the shadow volumes can be very hard to create geometrically, esp. with animated or moving objects/lightsources.

Shadow maps can handle *every* type of geometry in existance. Lightsources and objects can move, be animated, etc, there are no restrictions. They are also very fast to render. But it's a lot harder to implement correctly, and shadows will generally have soft edges (which can be a good or bad thing, depending on your application). It works on GF3+ only.

Here are some links to good papers/tutorials about both methods:

Shadow volumes
Stencil shadows
Hardware shadow mapping
GDC shadow mapping

Many more are on this site. Just run a search or check out the papers presented below the links given above,

/ Yann

[edited by - Yann L on August 17, 2002 12:25:45 AM]

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