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Backfacing polygons after perspective projection

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I''ve been writing some programs that do simple things (got to start somewhere) in order to render a 3D image. Let me give you an overview first: I perform backface culling before the perspective projection - the idea being to reduce the number of polygons that continue through the pipeline. The problem I have is that after the perspective projection, some of the polygons that were previously not backfacing now are. Am I doing something fundamentally wrong, or is there another test for hidden polygons after the projection? Thanks for your time and help.

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I''ve written my own software rendered engine. I do projection on ALL my vertices. Afterwards I do backface culling and depthsort on my polygons.
I could do backface culling before projection, but then I would have to check all vertices on every polygon for the projection calculation, probably making it a costly algo...

This all is offcourse scene-dependand!!!

- Maybe you are forgetting to transform some vertices?
- Did you do a correct inverse matrix transformation?

Doing other backface culling stuff after projection is really senseless!!! Believe me!!!

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Hold on a minute bas - you do your backface culling AFTER the perspective projection?

So, you have your object, bring it into viewspace by applying the inverse matrix on the camera (instead of the non-inverse matrix on the vertices), then you project into perspective followed by the backface culling?

If the answer is roughly yes, then I have some more questions...

BTW, I sent an email to your hotmail account, did you get it?

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