Split tube polygon across depth bands properly
commitf2d6d32562a2af6766b207734b31b25983b66648
authorOlly Betts <olly@survex.com>
Thu, 22 Jun 2017 06:07:48 +0000 (22 18:07 +1200)
committerOlly Betts <olly@survex.com>
Thu, 22 Jun 2017 07:33:43 +0000 (22 19:33 +1200)
tree30a5e062561d63f5a93dfa33f8f26b15cf625ca6
parente63ce4dfeca77432e070d9c23eac790024705a6c
Split tube polygon across depth bands properly

Previous we just set the colours of the corners and let OpenGL
interpolate, which gives odd looking results for polygons which
cross several depth bands - e.g. high chambers and long legs
down deep pitches.  The issue is worse for surveys without much
vertical range.

Currently the texturing of the split polygons isn't handled
correctly, but it wasn't before either.
src/gfxcore.cc