Sarien/Hires Badness

Sarien's hires mode causes some behavioural glitches, and should be removed in favour of leaving these Scale2x-style graphical enhancements to the ScummVM backends, especially since it can be made optional at that point.

The primary problem comes from AGI's priority screens, which control how the background scenery and the movable objects interact. For the uninitiated, you can think of it as a sort of "depth channel" (by analogy with an alpha channel). To add more complexity, control lines are also drawn on the priority screen, and they are responsible for the demarcation of no-go areas and for triggering various events (opening automatic doors, triggering traps, etc.).

AGI is a fairly touchy engine, and really requires pixel-perfect rendering internally; the hires mode thus causes a few problems, because it effectively smears the sharp borders that the rest of the AGI engine expects, leading to incorrect interpretation.

Here's a couple of screenshots from Space Quest 2 to demonstrate the kind of things that go wrong: