Adding Non-Stackable Attribute To Auras

[Nikos]

Many units have planned auras such as celtic druids, war elephants etc. The problem is that those are currently only designed for heroes and adding one to a normal unit makes the effect double for each nearby extra unit of that type, breaking balance. An option to prevent this would make auras much more handy and help implement missing features.

[Radagast]

You need to register the Aura + Entity template globally and only add the effect if it's not already registered if this option "isUniqueAura && isGlobalAura" is defined. Pretty straight forward, any half-way programmer can add it within some minutes.

For ranged auras it's a bit more complicated, when adding the bonus, check if such modifications in a row already exist in the target entity. Could be costly but works as it identifies an Aura.

When removing the bonus of one entity nearby pay attention to only remove the modifications if it's the last aura of this kind within the range. May be costly for performance.

[sanderd17]

Did you test this? I think I implemented this from the start. Per unit type, the aura is only applied once.

[elexis]

Refs #3792