Can someone explain how line-of-sight really works?

[jv123]

Can someone explain the deal with line-of-sight, breath attacks, hockey-sticks, awareness, projectability and all that jazz? I've never really understood it.

[PaulBlay]

Originally Posted by jv123

Can someone explain the deal with line-of-sight, breath attacks, hockey-sticks, awareness, projectability and all that jazz?

Maybe. I shall give it a go anyway.

In Angband there's LOS, viewable, and projectable.

Viewable means you can see it. Projectable means you can throw a rock at it. LOS means you (potentially) have a direct line of sight on it.

Angband LOS / viewable is generous - you can see some things even if you couldn't hit them with a rock (spell bolt, etc.).

#####
#  @ - I can see you there, dude.
#d###
# #

 #####
 # @ - I can hit you with a rock.
## ###
#d   #
######

Viewable (I think) includes fixes for walls so that you don't get blank corners in rooms and stuff.

#######
#
# @ - logically I can't know that red block of rock is there, yet i do.
#
#

Somebody will now come along to correct me. ;-)

[jv123]

Right! And how does targetable fit in to this?

[Nick]

Originally Posted by jv123

Right! And how does targetable fit in to this?

Targetable = projectable.

[Magnate]

Originally Posted by PaulBlay

Maybe. I shall give it a go anyway.

In Angband there's LOS, viewable, and projectable.

Viewable means you can see it. Projectable means you can throw a rock at it. LOS means you (potentially) have a direct line of sight on it.

Angband LOS / viewable is generous - you can see some things even if you couldn't hit them with a rock (spell bolt, etc.).

The difference between LOS and viewable is IIUC that LOS can include things which are unlit - viewable means either lit squares or warm bodies & infravision. This is the issue with ESP: things detected by ESP can be in LOS but not viewable. I am not convinced that r1439 has fixed this correctly.

[PowerDiver]

Originally Posted by jv123

Can someone explain the deal with line-of-sight, breath attacks, hockey-sticks, awareness, projectability and all that jazz? I've never really understood it.

The most important thing is the assymetry. When you are a knight's move away, the first step of projection is orthogonal and the second step is diagonal. That means that one of you can shoot the other without being shootable in return if there is a wall in the path in one direction but not the other. One way to remember is

##########################
..........................@
G########################

You want to target the ghost, but when it comes toward you it stays in the wall. That is not because it is smart, just because the first step is orthogonal rather than diagonal. If you want to shoot it on the way, use stone to mud above and step up and when it moves out of the wall step back down and shoot.

[PaulBlay]

Originally Posted by PowerDiver

The most important thing is the assymetry. When you are a knight's move away, the first step of projection is orthogonal and the second step is diagonal. That means that one of you can shoot the other without being shootable in return if there is a wall in the path in one direction but not the other.

That sort of thing illustrates the potential advantage of hex-grid based systems. Damned if I'd want to code one, though.

[Nolendil]

In case you haven't checked HexRogue, you can have a look here (Java required), it's interesting: http://www.hexatron.com/hexrogue/index.html