Stats System (Patreon)

Author: Hopfel

Hi, it’s Hopfel again!
Previous month I have worked on the stats system and added a lot of features. All graphics shown are “programmer art” as usual and not meant to be the final look.

Effects

Due to our movement system being physically simulated we have direct access to how much energy is burned with locomotion. In the following gif you see the energy usage to the left (yellow) and stamina bar (orange).

Effects such as Ready and Tired are triggered as the stamina bar reaches certain thresholds. These effects change attributes that have direct influence on the character.

We decided not to go with a purely timer based buff/debuff system but instead bind them to these bars. We will later add more bars, for example Toxicity when walking in toxic sludge or Suffocation when you run out of air. Those can also be added easily via mods.

Example: Once the stamina bar reaches the lowest threshold, the effect Fainting is triggered. This effect decreases movement speed and stamina regeneration while increasing energy usage.

The effect Tired is also active at the same time, accumulating to 19% movement speed.

Stats response

The stats bars can be changed by ingesting matter or influences in different ways. This can happen by absorbing matter through organs like the skin (e.g. toxic sludge), lungs (e.g. smoke) or stomach (e.g. food). It can also happen by forces (discussed in an earlier post) being applied (e.g. heat damage from a weapon).

With modularity in mind, each stats bar has a list of responses that convert incoming matter or influences to a change in value.

Example: Eating an item that has damaging matter can directly reduce your character’s health.

For this we have introduced a sections system, where each section identifies a part of the body that matter or influences can interact with.

Additionally they can also store matter.

Example: Your body has multiple different parts like the legs, torso and head. Losing your leg is equivalent to having no Bio matter in your leg. When you go through dirt, dirt matter is added to your leg.

Matter in those storages can later also be made visible on your character (e.g. dirty leg).

Example: An NPC covered in toxic sludge is killed in battle. A big creature swallows them. Their bodyparts are slowly digested away, giving the big creature Bio matter but also poisoning them.

One of the main challenges for this system is reducing the bandwidth needed to send this data via network. Every storage entry takes exactly as many bits as they need to.

Since the order of values is known, only the values themselves need to be sent.
For each value, only as many bits as absolutely necessary log2(#MaxCount) are sent.

Gradient generator

For later use we have extended the Unreal Editor with a custom Texture type representing gradients. These textures can be used in materials and exported to files. As most materials in our game use these gradients for coloring, having them be generatable in engine simplifies making new content greatly.