Wall polygons

[temnix]

Are wall polygons necessary in an area? I have already made a search map of this place I'm working on, marked walls as impenetrable obstacles, and true enough, the character can't see or walk through them. But the TIS I used as a starting point also has rows of turqoise wall polygons, not corresponding to anything any longer - I swapped the area around. Do I need them? Do I need to make my own? Can these polygons be the reason why special effects are cut off strangely in tight places and corridors? One of the types of polygons is a "shade wall." What's that?

While I'm at this, the area shows as jumbled. This time I didn't forget to include the TIS file generated from the PNG, in fact, the game crashes if I try to go to the area without a TIS, but with it there is a chaos of broken scenery. I thought at first that the TIS might have become corrupted somehow, but this is all brand-new stuff derived from the same PNG, the PVRZs and the TIS in a bunch. Any guesses as to why this might happen?

[temnix]

I want to bump up this thread and ask again: what is the purpose of polygons? I solved the problems mentioned here in my own area, but the area-of-effect drawing strangeness is probably due to polygons cutting in. What is it polygons do that simple search mapping can't?

[DavidW]

Polygons are part of the illusion of three-dimensionality. Character, and some spell-effect, pixels inside a polygon are dithered, i.e. drawn faded out, to indicate that the sprite is behind something. A tree, for instance, needs a blob on the search map (marking the region that you can't stand in because the tree is there) but also a polygon (marking the region where the tree is in front of you.