Thread: New Fish Models
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Old 06-23-2009, 10:47 AM   #25
flipper
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Join Date: Mar 2002

Location: Texas
Posts: 60
Techniques for handling order independent transparency have been around for a while, but they all involve running through the model geometry twice, once to establish depth and then again to apply the proper color. There are also feathering techniques you can use that just require multiple texture stages. That would at least get the edges of the fins rendered correctly.

The page at http://www.aorensoftware.com/blog/th...ever-heard-of/ discusses the problem in fairly easy to understand terms. There's a link to an Nvidia page with an example OGL app that uses the "depth peeling" technique mentioned in the link.

It's all still very expensive to properly handle a large amount of transparency/translucency in a scene. Jim's technique of sorting and rendering back to front is what most still rely on. What I've seen with a lot of models is the application of a special material to all of the non-opaque verts. Then D3D's attribute sorting is used once to get all of them segregated properly. Then all you have to worry about is the sorting of the faces within the non-opaque attribute set, since the other faces are rendered z-enabled. But you would still have to do some sort of depth layering to determine which non-opaque faces to render before and after the opaque, especially if they're inter-mixed depthwise like on a severely bent fish model.

I don't envy you this task Jim.
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