Legacy used some strange blending formula to calculate its colormaps for colored 3D floor lighting, this is not available in the software lighting mode, so for these the engine has to temporarily revert to light mode 2 to render them correctly.
- move a few variables from SceneDrawer to FRenderViewpoint.
The global r_viewpoint variable is left alone now to always represent the current viewpoint to the play code.
The main reason behind this change is to reduce the amount of global variables being used by the hardware renderer's scene processing code.
This removes 3 uniforms, consisting of 9 floats. Those were merged into other values that never get used at the same time.
It also moves the costly setup of the fixed colormap out of the render state into the 2D processing code.
Since 3D forces use of render buffers now, it is no longer necessary to draw the entire scene with the colormap active, meaning it can be handled more efficiently.
