derived-studio / drapedotnet

Data-driven game stat modeling framework for .Net

Drape

Drape is C# data-driven modeling framework for game stats/attributes. It is being developed for Unity but is not Unity dependent, thus can be used without it.

Important It is work in progress and current API is subject to change.

Motivation

Drape has been started as a side project facilitating management of numeric game stats. Main requirement was ability to create and register stats that then could be dynamically modified with stat modifier objects.

Goals

• Flexibility
• Extendability
• Small footprint
• Performance

Features

• Creating stats from code
• Stat registration and retrieval
• Dynamically calculated stat values
• Modifying stats with stat modifiers
• Local stat
• Creating stats using data files
  • JSON support
  • YAML support

Stat types

• Stat (simple stat)
• Modifier
• Resource
• Multistat

Stat formulas

Stat and modifiers

Stat components
---------------
B - base value
R - raw modifier
F - final modifier

Modifier types
---------------
f - flat
m - multiplier

Raw value formula
-----------------
R = (B + Rf) * Rm
Rf = Rf(a) + Rf(l) + Rf(g) + … + Rf(x)
Rm = Rm(a) + Rm(l) + Rm(g) + … + Rm(y)

Final value formula
-------------------
F = (R + Ff) * Fm
Ff = Ff(a) + Ff(l) + Ff(g) + …. + Ff(x)
Fm = 1 + Fm(a) + Ff(l) + Ff(g) + … + Ff(x)

Serialization

Json

JSON serialization supported with SaladLab fork of Newtonsoft Json.NET. You can get latest DLL file from here.

Private setter serialization supported with custom contract resolver method as described in Daniel's blog.

Yaml

Yaml serialization supported with YamlDotNet. Get latest release dll from here.

Consideration

• What is the reason of using final stat modifier (F)? Is it needed at all?
• BaseStatData.ToJSON() method only serializes public properties and doesn't allow to serialize members.
• Is BaseStatData needed? Can Stat be serialized directly?
• Applying global modifier to multiple stats of same type not supported. Eg. improved melee damage should apply to all melee damage type stats: sword damage, axe damage, etc.

Project setup

1. Clone repository
2. Open it from unity
   • Ignore console errors. You need to build it .dll.
   • Let unity create .sln solution file and open it from Visual Studio
3. Add ./Drape.Source/Drape.Source.csproj (existing project) to the solution
4. Build added Drape.Source project.

drapedotnet's Issues

Move example code into own repository.

Library should be independent from UnityEngine namespace.

Performance test needed

Registry factory should be public

Refactor Registry to StatRegistry to minimise clashes

Local stats dependencies error

If local stats is created based on reference stat that contains dependencies it throws and error.

Registry factory constructor should allow single installer as a argument.

RegistryFactory registryFactory = new RegistryFactory(new List<IInstaller>() {
	{ new YamlInstaller<Stat, StatData>((Resources.Load("example03/stats") as TextAsset).text) },
	{ new YamlInstaller<Resource, ResourceData>((Resources.Load("example03/resources") as TextAsset).text) },
	{ new YamlInstaller<Modifier, ModifierData>((Resources.Load("example03/modifiers") as TextAsset).text) },
});

Should work with

RegistryFactory registryFactory = new RegistryFactory(new YamlInstaller<Stat, StatData>((Resources.Load("example03/stats") as TextAsset).text));

Removing dependencies throws "out of sync" error

Add support for Local Resource

I want to be able to use create local version of Resource stat.

yaml installer should be public

Factor error

Factors should be added together before multiplication

Local stat dependencies limitations

Currently stat dependencies can't be modified. It works ok for RPG like dependent properties, eg:
_ melee damage -> strength _

Local stats, however, since are created on the fly should have local dependencies. Framework doesn't allow that. To fix the problem in Forsaken Expanse I have introduced few modifications to the framework.

IUpdatable interface should be public

Prevent adding local stat to registry

Local stat shouldn't be added to a registry. It is dynamic value based stat that only stores reference to a registered stat.

Problem with local stats

Currently if different entities need stat with the same id,, each of the entities would have to use own stat registry, which makes it difficult to apply common modifier to all of them. It requires manual intervention.

Base stat value currently can not be modified

Test coverage is needed

Local stat has no dependencies

I want to be able to add and removed dependencies from Local stat.

Add Stat.ContainsDependency helper method