A Framework for Special Abilities

I have been working on the framework that will handle the characters' special abilities in my as-yet-unnamed RPG.  Special abilities include skills and spells, as well as the effects of equipment and consumable items.

The main idea is that an ability is triggered and has certain effects, some of which are instant and some of which are delayed.  For instance, if there was a spell called 'Frog', it would be triggered when the character casts the spell. The effect would be to apply a frog transformation on the target, and to put a 'cancel transformation' event in the event queue, to be applied when the spell would wear off.

Some typical trigger use-cases that I considered were:

• An active ability registers its trigger object(s) with a player or AI, indicating that it needs to be activated when the controller sees fit.
• A semi-passive ability registers itself with its character object, giving a trigger object that specifies when it should activate.
• A passive ability triggers when the ability is gained.

It looks like all abilities can be handled with triggers and effects, but during transformations, possessions and body swaps there will need to be special handling of non-instant and delayed-effect abilities.  Maybe the event queue is not the best way to handle long-term effects.

Back to the drawing board!