Add the boulder trap.

[Bertram25]

Prerequisite: #194

@Danimal696 @hwoarangmy @akien-mga Feel free to correct those little specs as I might have missed something. :)

The trap boulder is triggered when an enemy is within the 5 nearest tiles.
A boulder appears and rolls slowy (movement speed to define) toward the unit.
When reaching a wall, the boulder change its direction randomly (making it more hazardous)
After two or three bounces, it breaks and disappears.

The trap is out of order after being triggered.

Model: http://forum.freegamedev.net/viewtopic.php?p=59832#p59832
Icon: http://game-icons.net/lorc/originals/stone-sphere.html

[hwoarangmy]

I think the idea is good but it should trigger when a creature is closer. This trap will be a powerfull one and if it triggers too early, it would be too easy to pickup the creature before it is hurt.

[Danimal696]

closer trigger +1

[Bertram25]

Np. I guess it's something we'll have to fine-tune anyway.

[hwoarangmy]

In the actual code, boulder trap is supposed to be directional. For now, I've set it to trigger only when a creature is on its left as there is currently no way of setting it. Do we want to keep that way (if no, more generally, do we want to keep traps that can trigger in only one direction) ?
If yes, does someone have an idea how to represent that ? A popup ? Some visual artefact ?

[Bertram25]

I think we don't want limited traps. The boulder trap should ideally trigger on the straight tile the victim is, IMHO. @hwoarangmy How do you see it, as a player?

[hwoarangmy]

As a player, I could understand both. But if you prefer not being a directional map at all, I will change that and add it in the PR :-)

[Bertram25]

Hmm, let's vote! @Danimal696 @akien-mga @oyvindln ?

[Danimal696]

i would prefer it detects the enemy and triggers in the direction it is.