Add mod setting for custom/fixed seed

init.lua

@@ -55,6 +55,10 @@ dofile("mods/noita-mapcap/files/ui.lua")
 
 ---Called in order upon loading a new(?) game.
 function OnModPreInit()
+	if ModSettingGet("noita-mapcap.seed") ~= "" then
+		SetWorldSeed(tonumber(ModSettingGet("noita-mapcap.seed")) or 0)
+	end
+
 	-- Read Noita's config to be used in checks later on.
 	Check.StartupConfig = Modification.GetConfig()
 

settings.lua

@@ -128,6 +128,14 @@ modSettings = {
 		foldable = true,
 		_folded = true,
 		settings = {
+			{
+				id = "seed",
+				ui_name = "World seed",
+				ui_description = "Lock the world to the given seed\n \nClear field to use a random seed.",
+				value_default = DebugAPI.IsDevBuild() and "123" or "",
+				allowed_characters = "0123456789",
+				scope = MOD_SETTING_SCOPE_NEW_GAME,
+			},
 			{
 				id = "grid-size",
 				ui_name = "Grid size",