Discussion:Field of Vision
Half-width walls, center to center
This is a symmetrical system.
Consequences:
################D @
Fig 1. @ can see D, D can see @
##D ## @
Fig 2. Indeterminate (probably resolve to not visible).
#m # @#
Fig 3. Vital that @ can see m in this case.
...................... .@# M ......................
Fig 4. @ cannot see M (by zero-width blockage sub-rule - see fig 2)
....... .@..... ...#... ..... . .......
Fig 5. Discontinuous gaps in viewable area (by zero-width blockage)
Monsters occupy half the width/height of grid
Monsters, characters, items are in the center of their grid's square taking up half the width/height. If lines from any point in the @'s sub-square can go to any point in the M's sub-square without crossing a wall then each is visible by the other. Walls take up the full grid square.
This is a symmetrical system.
Consequences.
#####D###### @
Fig 6. @ cannot see D.
####D####### @
Fig 7. It is indeterminate whether @ can see D or not (zero-width cross).
###D######## @
Fig 8. @ can see D and D can see @