glShadeModel is depreciated. So, how, exactly, do we do flat shading now?
I want to make a retro-style game like Spectre. I'm trying to stay away from depreciated functions. I DO understand that it will work for the foreseeable future. Still, depreciated means going away at some point and I would like to stay ahead of that.
The problem is that the only way to do flat shading that I can find is via glShadeModel. I cannot find any method of doing flat shading via the programmable pipeline and what little I could find mentioning flat shading states that it cannot be done. Is this correct?
The only idea that I can come up with is to do all transformations and lighting calculations on the CPU side and send the calculated polygon shade to the GPU via a uniform. That doesn't seem to be the most efficient method. Unfortunately, it seems to be the *only* method.
How can I do this? Is this going to be addressed in a future gl version? Flat shading is still needed in 3D modelers and CAD/CAM applications.