There are two major computations performed by the battle system. First, space combat is computed. Once this part is over, and provided there are still attacking ships in orbit, computations regarding ground combat are performed. Once these two main chunks have been computed, experience points are attributed.

This posts attempts to explain what the various steps of each computation are and how they work, generally speaking.

This flowchart shows the essential steps of the battle computations. Exit conditions and various internal steps have been omitted for clarity.

Space combat

The first step of space combat is fleet updates. When attacking fleets first start a battle or when fleets join an ongoing battle, they suffer “time dilation” which causes them to be less efficient for some time. This time dilation effect must be decreased over time.

Once fleets’ time dilation strengths have been updated, ships need to undergo various systematic updates: ships that can repair themselves will regain hit points, countermeasures will recover from previous damage absorption, and weapons will charge or cool down. If no weapons are ready to fire, then the space combat computation is over.

If there are weapons ready to fire, the first step is target selection. If a weapon already has a target, there’s a chance it might still select another target – this depends on a fleet’s strategy (for planet-based weapon platforms, there is a fixed, very small probability of target change). If such a change needs to occur, or if the weapon had no target for some other reason, it will seek a target based on the fleet’s (or the planet’s) tactics – basically, it can select targets by size, weaponry or defences, with different priorities. An attacking fleet’s strategy will determine whether the weapon may target the planet’s infrastructure.

Once weapons have selected their targets, they may fire. A computation is performed to determine whether the weapon actually hits, whether the shot may be intercepted and which amount of damage it would cause on a “naked” ship from various variables such as the ship’s experience, current hit points, manoeuvrability… When a weapon fires, there’s also a small chance of a critical hit, which cannot be intercepted and deals twice as much damage.

Depending on strategy settings, some ships may try to intercept shots aimed at other fleets or at the planet. Such an interception depends on how successful the aim was, and on various other factors such as how many hits the intercepting fleet might sustain. A successful intercept will cause the ship that intercepted the shot to take the damage – which is particularly useful to defend planets. No ship can intercept two shots in a single battle update, however.

Once the destination of all shots have been computed, the corresponding damage is inflicted to ships and buildings. Ships may have countermeasures which can sometimes absorb part or totality of the damage. Of course, should a ship or building reach 0 hit points, it is destroyed. In addition, any ships or buildings that provide ground armies will have their army strength reduced accordingly.

Ground combat

Once space combat has been resolved, and provided there are any attacking ships left, the computation of ground combat begins.

First, the ground defence advantage is computed. It is determined by the amount and type of ships supporting ground troupes, by the amount and type of military buildings, and by the population’s happiness.

The support that fleets provide for ground armies may vary depending on a fleet’s current strategy. Fleet strategy also determines whether ships that carry armies should drop the troupes to the planet’s surface or attempt to extract them.

Once the system knows which armies are on the planet, providing there are both attacking and defending armies, ground combat is computed. The damage dealt by either side is mostly determined by the advantage value, although their respective sizes has an influence. Finally, damage is applied to armies (and to the corresponding ships or buildings).

Assigning experience points

After all actual fighting has been computed, experience points are given to ships (buildings will have no XP in milestone 2, but that might change later). The amount of experience points granted to a ship is determined by the damage it inflicted to other ships, by the shots it intercepted, and by the damage the ground armies it carries inflicted.

Next time…

… I will explain the mechanics of space combat more precisely, and how it is affected by fleet tactics and strategies.

In order to make sure that the fleet-related information is complete, the most crucial component is the battle system. It affects a few things on planets, and has far-reaching consequences on the whole ship design and fleet management system.

The most basic types of information handled by the battle system are the definitions of weapons and their countermeasures. The basic principle – three types of weapons vs. three types of countermeasures – has been described many times. This time I needed to come up with the details.

Weapons

In addition to their types, weapons will have four characteristics.

• Base damage is the “standard” amount of damage a weapon deals when it hits. Depending on circumstances, the actual damage may be different.
• Accuracy describes the probability that, in a perfectly neutral environment, the weapon actually hits what it is aimed at.
• Charge time and Cool-down time are delays that occur before and after the weapon is fired.

It is easy to compute the average damage inflicted by a weapon at each tick. This allows weapons of the same level, but of different types, to be relatively different in behaviour without sacrificing game balancing.

For example, one could imagine a beam weapon that fires once every two ticks, with a base damage of 5 and an accuracy of 80%. This weapon would inflict, on average, 2 points of damage every minute. It is easy to create a mass driver with similar results; such a weapon would fire once every 4 minutes, inflicting a base damage of 20 with an accuracy of 40%.

In battles, each weapon fires independently. Weapons on the same ship may have different targets – while this makes no real sense for fighters, it prevents really big ships from concentrating their fire on a potentially much weaker target.

Countermeasures

Just like weapons, countermeasures have a few more characteristics in addition to their type.

• Maximal absorption is the maximal amount of damage that can be absorbed by a countermeasure before it becomes inefficient.
• Efficiency describes the probability that a countermeasure intercepts damage.
• Absorption recovery is the amount of absorption points recovered at each tick after damage absorption.

Balancing for countermeasures is a little more tricky than it is for weapons. I chose to use a (totally artificial) value corresponding to the efficiency multiplied by the amount of minutes a countermeasure would be efficient for if it was absorbing half its maximal capacity at each minute:

Efficiency * Maximal absorption / ( Maximal absorption * 0.5 – Absorption recovery )

Obviously, this means that the recovery should always be lower than half the maximal absorption…

In battles, all countermeasures of the same type act as one single countermeasure on a ship, with an weighted average used as the efficiency and sums for both the maximal absorption and the recovery.

Balancing weapons and countermeasures

No countermeasure can prevent damage indefinitely unless its recovery rate is higher than the damage being inflicted. While this might happen when pitting e.g. a very big ship against a single fighter, it makes it relatively easy to balance weapons and countermeasures of the same level – a weapon’s average damage should be slightly higher than its respective countermeasure’s recovery rate.

Next time…

I am still working on the battle system at the moment. My next post will be about fleet tactics and strategies, as this has been (is?) a major headache.

Missile countermeasures come in three different types.

• Anti-missile weapon systems (AMWS) are weapons that try to shoot incoming missiles to destroy them; this type of countermeasure uses a lot of space on board.
• Electronic missile countermeasures (EMC) try to fool an incoming missile’s guidance system to prevent it from reaching its target. They are much smaller than anti-missile weapon systems, however they are very demanding on the ship’s generators.
• Physical missile countermeasures (PMC – for lack of a better name) use advanced knowledge of the universe’s structure to get rid of incoming missiles. While these systems use quite a lot of space and energy, they are more efficient than EMCs or AMWSs.

Do you have other ideas of possible missile counter measures?

Do you have ideas of other categories of missile counter measures?