On the complexity of missile combat

This bog post is the kick off post for ADOM II 0.3.0 development. The past two days did not unearth any particularly disturbing bugs in ADOM II 0.2.7 (although a couple of very nice enhancement ideas and game balance improvements already have been suggested). According to my evaluation none of them are harmful to the enjoyment of the game so that I decided to move on and start the development of ADOM II 0.3.0. I already have updated DevState in order to inform you about the most pressing issues I want to tackle with ADOM II 0.3.0. Despite "release early, release often" 0.3.0 is going to take a while longer (it probably will get released around the end of June).

Now for the main topic of this blog post: missile combat.

Let's look at the past first. In ADOM Classic missile combat is rather simple:

• The player declares his intention to shoot a missile or throw a weapon (by keyboard input).
• ADOM checks all prerequisites and either aborts or shoots the missile.
• The shot itself is instantaneous. The path is calculated, the flight of the missile is animated, a target is reached, hits or misses are resolved, etc.
• The game continues.

I want this to be different (and internally a lot more complex) for ADOM II as I believe that the new enhanced implementation will add tons of interesting details.

The most basic and most important change will be that shots no longer are going to be instantaneous. While this might sound like a trivial change the implications are tremendous. Let me explain:

• In ADOM II a basic unit of action (internally called a "tick") is made up from 1000 minuscule units of time. One base time unit (1000 ticks) basically is equivalent to 10 seconds.
• As soon as a "shot" (my current abstraction name for a missile attack) takes place and no longer is instantaneous it becomes a thing in the game world - even if just for a brief while.

And that's already the exciting thing. If a shot (a flying arrow, a thrown dagger, maybe even a thrown opponent - think of monks) becomes an actual entity in the game world and moves at high speed from source to target there are possible interactions:

• A monster or the PC might step into the flight path, actually begin accidentally hit by the missile.
• The target might move out of the flight path if he or she gets very lucky (the target would have to be able to move in the split second between shooting and hitting).
• Other environmental effects might influence the shot (e.g. high liquid levels might stop or destroy it, strong gusts of wind might change the course, an exploding fireball might catch up with it before the shot reaches the target thus destroying it, etc.).

Sadly the complexity of the implementation also rises:

• A shot needs to be an abstraction for everything from a thrown being to an arrow launched from a bow.
• A shot needs to be able to actively influence the environment (what happens if a troll thrown by a monk hits a door?).
• A shot needs to be influenceable by the environment (fireballs, wind, liquids, etc.).

While the complexity is quite high (as all the things above need to take into account the material and speed of the shot, the makeup of the intercepting environmental factor, etc.) I think it's definitely worth the effort since both combat and the general environment become a lot more interesting.

Just imagine a trap at the end of a very long tunnel - it shoots highly poisonous arrows but the PC just needs to move around a short corner... magic that speeds up movement extremely suddenly might become very desirable... and so on.

Additionally I'm currently pondering to allow more targets for missile attacks:

• Monsters are the trivial targets.
• Items might be interesting targets (think about a quest of the type "prevent the evil lich Marcarak from gaining the vial of might - and when you finally reach the vial of might Marcarak also already is there and moving towards it to get it - it might be nice to decide whether to try destroying the vial before Marcarak gets to it or take some other gamble).
• The environment itself might be interesting (maybe smashing doors by repeatedly shooting at them with special ammunition).
• It might be interesting to add traits in the form of "can stop missiles" to other things in the game (walls are a natural candidate) in order to be able to build interesting spells in the 0.4.x development line (e.g. "area of protection from missiles").

It also would be a great ability for tinkers to be able to craft special ammunition. And high-level archers also might get some skill in that - or be tempted to travel to large cities to buy such stuff in Tinker Bazaars.

And finally it could be very interesting for combat to have varying missile speeds... e.g. thrown daggers being slower that arrows, which in turn might be slower that crossbow quarrels. So there are ample ideas I'm gambling with right now and I expect missile combat to be a lot more interesting and exciting in ADOM II :-)

Further ideas and discussion naturally is extremely welcome!