| RE: [AD] Patch for the documentation of polygon_z_normal() |
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- To: <alleg-developers@xxxxxxxxxx>
- Subject: RE: [AD] Patch for the documentation of polygon_z_normal()
- From: "Robert Ohannessian" <ROhannessian@xxxxxxxxxx>
- Date: Tue, 7 Jun 2005 08:58:58 -0700
- Thread-index: AcVreU+XcYhu3EvHQ6OkVzwKV49LzgAADLHQ
- Thread-topic: [AD] Patch for the documentation of polygon_z_normal()
> So what would be a good method for back-face culling without first
> converting into screen space? The advantage this has is that it saves
a
> persp_project() call for any vertices who'se polys are completely
> obscured.
The trouble is that back-face culling requires you to know where your
geometry is in screen-space. You can't just use clip space / eye space
for this, or you'll either miss faces that could be back-face culled, or
you'll cull too many faces.