1.2/PBR thoughts

[RichardDastardly]

• Add single reflection probe to any vessel with PBR shader - probe should ignore vessel layer ( yes this means no reflections from vessels but performance would be atrocious otherwise ). Perhaps investigate if it can ignore the host vessel only. I think someone did a little work on this when 1.1 arrived
• Instancing support is SM4/OGL 4.1+, but is so simple to implement that it's worth pursuing. Check standard shader for surface shader implementation. Performance increase on KSP with many of the same parts should be worth it ( a reason to use DX11 again ).