When I first started on porting the IUE Planetary Engine I tried to bridge the Gap between Open GL and Directx (XNA) by using a C# framework that enables me to use OpenGL.
Well the framework used is the Open Toolkit Library and is, like XNA, more than just a graphics framework. It has besides OpenGL support for input/music and AI. I mainly used it to see if the Geometry part of the porting is correct. And besides that it has some benefits over debugging a VC++ 6.0 application in an obsolete Visual Studio IDE and Visual C# Express 2010.
I’ve spent a week to see something in the viewport, but It didn’t. Than I suddenly found that the ViewMatrix was wrong (If something doesn’t render always look first at the ViewMatrix and than the world matrix).
Boom, a full planet showed up!! After fixing some input I could seamlessly zoom in and out of the planet at high framerates! So It’s a big step ahead into making this work….