add post process ccvar

Content.Shared/CCVar/CCVars.Graphics.cs

@@ -0,0 +1,14 @@
+using Robust.Shared.Configuration;
+
+namespace Content.Shared.CCVar;
+
+public sealed partial class CCVars
+{
+    /// <summary>
+    /// Toggle for non-gameplay-affecting or otherwise status indicative post-process effects, such additive lighting.
+    /// In the future, this could probably be turned into an enum that allows only disabling more expensive post-process shaders.
+    /// However, for now (mid-July of 2024), this only applies specifically to a particularly cheap shader: additive lighting.
+    /// </summary>
+    public static readonly CVarDef<bool> PostProcess =
+        CVarDef.Create("graphics.post_process", true, CVar.CLIENTONLY | CVar.ARCHIVE);
+}