VIS phase minor switches:
- Only calculates rough visibility data. Quick and dirty, not actually useful for VIS purposes.
- Will merge the bsp leaves (except for hint portals) before calculating the visiblity list.
- Will merge the bsp leaves before calculating the visibility list.
- Disables the passage visiblity algorithm. Passage VIS is a bit faster and tighter than the old algorithm.
- Disables the sorting of portals by complexity. Sorting speeds up visiblity calculations.
- Will use the passage visibility algorithm only.
- Disables the automatic deletion of the .prt portal file after VIS finishes.
- Enables verbose mode. Always use this.