Mask maps are now mostly included in the Tile class. While refactoring terrain map I realized that Gameview class has to be refactored. It's a class that draws the final 17x17 tiles on screen. Previously it had both static and dynamic light maps copied into a special 35x35 buffer which includes nearby light sources still visible from that 17x17 view.
However I found out that there is no need to copy the light information to the gameview, or anything else, because Tile class can include them. Even dynamic light values can be stored in Tile and recalculated on a specific area around the player to show only light sources that can be visible to the player.
The original Gameview was a result of copying FOV data and then determining how tiles and light would be displayed, but FOV was moved away from Gameview even before I started this refactoring and I didn't figure out how much there was unneccessary copying until now. Another great thing is that the new code will completely remove difficult coordinate transformations. Also, tile graphics are now stored in Gameview which is a wrong place, because they belong to GUI class. Gameview wont become completely useless, because it still has the update map which speeds up displaying of tiles by remembering empty tiles from previous turn and not drawing them at all.
Even now the gameview routine is fast, but it's going to be really fast after this refactoring. Well, I'm going to need that speed to include lights that have FOV routine in them. At the moment lights are just simple spots that don't know anything about walls or other obstacles.