- 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.
This was all over the place, with half of it using the function and half doing incomplete checks on the underlying variables.
Also did some optimization on the IGNOREHEIGHTSEC flag: Putting it on the destination sector instead of the model sector makes the check even simpler and allows to precalculate the effect of 3D floors on the heightsec, which previously had to be run on every call and made the function too complex for inlining.