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Marvin Fröhlich
03-30-2008, 02:17 PM
hi

I have a problem rendering transparent (blended) models. By models I mean non-simple geometries, where parts of the geometry may be behind other parts.

Rendering a geometry like this it is rendered differently from different view-points. Sometimes transparency even disappears completely. The model is only rendered perfectly from a very certain point of view.

I know, that this is an ordering problem. I do render blended objects after opaque ones and I do sort blended ones front-top-back (farer objects first). But I don't have a chance to sort the geometry's polygons without extremely huge cost (I would have to rebuild the VBO or DisplayList). I read this (http://www.glprogramming.com/red/chapter06.html#name1) article (especially the section about "Three-Dimensional Blending with the Depth Buffer". But it doesn't seem to work.

Is there a general solution for this issue?

Please ask, if you need more information or if I wasn't clear enough.

Thanks in advance.

Marvin

ZbuffeR
03-30-2008, 02:37 PM
There are "depth peeling" techniques that allow to display correctly up to a dozen of blender layers.
Modern (GLSL) code :
http://http.download.nvidia.com/developer/SDK/Individual_Samples/samples.html#layerz_3x
Some background on the technique,, with an older implementation :
http://developer.nvidia.com/object/Interactive_Order_Transparency.html

Marvin Fröhlich
03-31-2008, 04:06 AM
Thanks for the quick reply. Looks like a solution. Thanks.

Marvin