From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 11 Mar 2022 21:48:17 +0000 (+0200)
Subject: Flip normal if a surface faces away from the camera
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=88c401224220010cb71426fafc5173661c4d48a3;hp=88c401224220010cb71426fafc5173661c4d48a3;p=libs%2Fgl.git

Flip normal if a surface faces away from the camera

This gives correct two-sided lighting for non-closed meshes, which may
be used for tree leaves and such.
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