Refactor GUI to use shaders and to be GLES and GL3+ friendly
This a big part that prevents OpenMW from being able to take advantage of GL3+ and GLES OSG renderer.
The latest versions of MyGUI support not just GL2 but also now GL3 and GLES backends: https://github.com/MyGUI/mygui/blob/MyGUI3.4.1/CMakeLists.txt#L137-L151
If we can get around this by just using OpenGL MyGUI backend, great. Otherwise we'll need to use their GL3 or GLES targets to get this feature. We'll end up having to do this with OSG as well (telling it to support rendering against GL3 or GLES).
The big question is, can we link against all 3 targets in MyGUI, this hasn't be investigated yet. However this is only one part of the problem. The GUI itself needs to made to user shaders.
Edited by Evil Eye