I have also considered real time but it feels like it's one upper level of difficulty to code/complexity to the game so I might skip it and make it more like the Elvira games.
Ok, you have the exact solution to the viewpoint as I have with alot of IF's. As long as it works I guess.. But I can't escape the feeling that it should be a easier/shorter way to calculate view
About the graphical assets, why not "borrow" some graphics from Eye of the beholder / DM as a start and then edit them beyond recognition for your own needs?
I wish you good luck with the game!
Believe me, I've considered asset flipping. Unfortunately my viewpoint is way bigger than EOB, DM, Captive, Knightmare, Walls of Illusion, Ishar, etc. Also my perspective is different if you look at it; the "camera" is equidistant from floor and ceiling. Also also, none of the above have murderous antelopes with horns and tusks, soldier ants with chitin spears, or manticores. (I don't want boring monsters such as orcs, goblins, undead, etc.)
And there must be an easier way to calculate it, I'm sure, however, brute forcing seems to work for now.
Don't knock Elvira / Waxworks. They're good games. I'm told that they actually started with a graphical MUD engine and basically bashed it until it fit their purposes. I think you could probably do the same in STOS no problem. Compact each location image together with its mask (a secondary image that might include all variants such as objects taken / not taken, etc.) and a directory of where each mask element goes, a room description, exits and where they go to, and examine descriptions into a single .MBS file, then load it in, BLIT everything into place, wait for player input, and you've probably got something a bit like the Legend Interactive adventure games on PC (Companions of Xanth, Spellcasting series, Death Gate, Shannara, etc.)
I believe one of our number in the Facebook group has also worked out how to do a resolution split as well, so you can have low res to show the image in colour and med res to make the text less chunky at the bottom...