Add preprocessor define symbols to Unity builder

Context

Basically, we have a few preprocessor macros that we use and it looks like there isn’t an easy way of doing that without creating a custom builder. However, I think being able to specify custom defined symbols via yaml would be really nice!

So I was thinking something like this

defines:
    - STEAM

I can implement this, if this is something you’d think would be worth having.

[pearcemichal]

I got it working, I will post the process here for anyone else that comes across this:

first, I set up my project to use a custom build script by following the steps in the documentation here: https://game.ci/docs/github/builder

relevant sections are buildMethod and customParameters

after copying the supplied template buldMethod.cs file into the Assets/Editor/UnityBuilderAction folder, in the GetValidatedOptions() method, I added the following if statement:

if (validatedOptions.TryGetValue("DEMO", out string _))
{
    string definesString = PlayerSettings.GetScriptingDefineSymbolsForGroup ( EditorUserBuildSettings.selectedBuildTargetGroup );
    definesString += ";DEMO";
    PlayerSettings.SetScriptingDefineSymbolsForGroup(EditorUserBuildSettings.selectedBuildTargetGroup, definesString);
}

this will look for a customParameters -DEMO, and if it finds it, it will add it to the scripting defines list.

the yml code:

with:
    targetPlatform: StandaloneWindows64
    buildName: debris_field_demo_PC
    buildsPath: demo
    versioning: Semantic
    buildMethod: UnityBuilderAction.BuildScript.Build
    customParameters: -DEMO

[pearcemichal]

in the past, I used the scripting defines to create separate release and demo builds for my game. based on the description of the customParameters, I thought something like customParameters: -DEMO would work, but based on my testing it does not.

I do not understand what the stated solution to this is. could you please describe the process in more detail? (or add it to the documentation somewhere, for future reference)