Game Foundation Tutorials

Adding mutable properties with Stats

With the Json Detail, we've seen how to add static properties to enhance the item definition. This system wouldn't be complete without a solution to play with mutable data at the instance level. A piece of equipment can wear down, a character can level up, ammunition can decrease, ... those properties are mutable.

To solve this aspect, Game Foundation features a Stat System. This system involves three components:

  1. the StatDetail
  2. some Stat Definitions
  3. the Stat Manager

We'll see in this tutorial how to define the first two, and the following tutorial will focus on using Stat Manager to play with them at runtime.

Details are static data... the StatDetail is also a static configuration, but it defines with stat the instance will expose as mutable properties.

Create a Stat Definition

We need first to create a Stat Definition. This is a named property, with a type (currently only int and float are supported).

To create a Stat Definition, open the Stat Window by selecting Window → Game Foundation → Stat

The layout should now look familiar. Otherwise please check the inventory tutorial.

We'll focus here on the creation form, which shows a specific parameter.

The Value type is the type of this stat. Every catalog item using this stat will expose the same property, with the same type.

Create your Stat Definition according to the screenshot above.

  • Display Name: "My Int Stat"
  • Id: "myIntStat" (let the system fill this field for you)
  • Value type: choose Int

Adding the Stat Detail to an item definition

We've seen in the previous tutorial how to attach details to a catalog item.

Please follow the same steps to add the Stat Detail to our item definition.

Adding a Stat to the Stat Detail

The Stat Detail Editor

The Stat Detail section show the list of the [stats] and their default value.
At the bottom of the section, you can see a popup list and an Add at the opposite side.

Select the stat you've just created ("My Int Stat"), then click on Add.

The Stat Detail Editor with a stat

Now that the stat is added, you can define a default value (we've put 42). That means when the item instance is created from this item definition, the value of its "My Int Stat" will be 42.

Conclusion

We can now configure an item definition with mutable properties. The next step is to manipulate this mutable property at runtime.