Since these do not fully get processed sequentially the contents need to be preserved until needed.
This required getting rid of the global tsprite array. Polymost still uses a static vatiable, though, but this is only accessed in polymost-exclusive code.
Like for Blood, the Polymost-only code has been moved aside.
Closer examination of the preparations the engine is doing for rendering SE40/150-portals shows that all this was merely done to avoid glitches with a two-phase rendering setup - nothing of this will be needed for doing it properly.
They can just be treated as run-of-the-mill stacked sectors. when using hardware rendering capabilities for clipping.
