Mega Tree API

API reference

Every public type and member in MegaTree.Api, flat and anchored.

Namespace: MegaTree.Api. Assembly: MegaTree.dll. Nothing outside this namespace is public - the rest of the mod is internal on purpose, so there is exactly one door.

Every member here takes or returns plain objects and delegates. Nothing in the surface is a Sprite, a Color or a GameObject, so a mod can use the API without referencing a single Unity UI assembly.

MegaTreeApi

public static class MegaTreeApi

Member	Description
`const string ModGuid`	Always `"MegaTree"`. Use it in `[BepInDependency]`.
`static readonly int ApiVersion`	Contract version of the installed dll. `readonly`, never `const` - see Versioning. Currently `1`.
`MegaTreeModule ForPlugin(string pluginGuid, string tabName)`	Creates or renames your sub-tab and returns your module. Call once, keep the result. Never returns null.
`int GetLevel(string nodeId)`	Owned levels, clamped to that node's `MaxLevel`. `0` for an unknown id. Dictionary lookup - cheap enough for a hot patch.
`bool IsRegistered(string nodeId)`	Whether the id is currently in the tree.
`void RefreshUi()`	Ask an open tree window to repaint. No-op when nothing is open, and it only marks the view stale - calling it in a loop costs one redraw.
`event Action<string,int> LevelChanged`	`(nodeId, newLevel)`, after a buy or a sell-back. All nodes, including built-ins. Does not fire for a level restored on registration.
`event Action Apply`	About twice a second, after Mega Tree's own effects. Not a per-frame hook.
`event Action<int> SaveLoaded`	`(slotIndex)`, once levels for that slot have been read.

MegaTreeModule

public sealed class MegaTreeModule - obtained from ForPlugin, never constructed directly.

Member	Description
`string PluginGuid { get; }`	The guid you passed in.
`string TabName { get; }`	Your sub-tab label after trimming to 18 characters.
`UpgradeHandle Register(UpgradeDefinition definition)`	Adds one upgrade line. Never throws; check `.Success`.
`bool Unregister(string nodeId)`	Removes one of your nodes. The player's level is kept in the save.
`void AddTranslations(string locale, IDictionary<string,string> values)`	UI strings for one language. Accepts `"pt-BR"` or `"Portuguese"`. Mega Tree's own keys are skipped. Details

UpgradeDefinition

public sealed class UpgradeDefinition - a plain object with public fields. Full explanations on Node definition.

Field	Type	Default
`Id` required	`string`	-
`DisplayName`	`string`	`null`
`NameKey`	`string`	`null` (auto: `<id>.name`)
`MaxLevel`	`int`	`1`
`BaseCost`	`float`	`1000`
`CostMultiplier`	`float`	`1.8`
`CostForLevel`	`Func<int,int>`	`null`
`SellBackRate`	`float?`	`null` (50%)
`Icon`	`UpgradeIcon`	`null`
`DescribeLevel` required	`Func<int,string>`	-
`IsUnlocked`	`Func<bool>`	`null`
`LockedReason`	`Func<string>`	`null`
`RequiredStoreLevel`	`Func<int,int>`	`null`
`ComingSoon`	`bool`	`false`
`SortOrder`	`int`	`0`
`LegacyIds`	`string[]`	`null`
`OnLevelChanged`	`Action<int>`	`null`
`OnApply`	`Action`	`null`

There is no category field. Every registered node lives in the Mods tab, in your sub-tab. Why

UpgradeIcon

public sealed class UpgradeIcon - built through factory methods.

Member	Description
`static UpgradeIcon Builtin(string name)`	One of the 14 built-in icons. Unknown names fall back to a generic one. List
`static UpgradeIcon FromPng(byte[] data, bool whiteSilhouette = false)`	Your own PNG. Ship white artwork with alpha, or pass `whiteSilhouette: true`.

UpgradeHandle

public sealed class UpgradeHandle - what Register returns. Always non-null.

Member	Description
`string NodeId { get; }`	The id you registered.
`string OwnerGuid { get; }`	The plugin guid that owns it.
`RegisterResult Result { get; }`	Why it succeeded or failed.
`bool Success { get; }`	Shorthand for `Result.Success`.
`int Level { get; }`	Current owned level. Same as `MegaTreeApi.GetLevel(NodeId)`.
`bool Unregister()`	Removes the node; the level stays in the save.

RegisterResult

public sealed class RegisterResult

Member	Description
`bool Success { get; }`	True for `Ok` and `Replaced`.
`RegisterStatus Status { get; }`	Machine-readable outcome.
`string Message { get; }`	The same text that went to the log.
`string ToString()`	`"Status: message"`.

RegisterStatus

public enum RegisterStatus

Value	Meaning
`Ok`	Added.
`Replaced`	Same plugin re-registered the id; level kept.
`MissingField`	Null definition, or no `DescribeLevel` / no name.
`InvalidId`	Not `prefix.name`, or bad characters.
`ReservedId`	Starts with `megatree.` or `mt.`
`OwnedByAnother`	Another plugin owns the id.
`InvalidLevels`	`MaxLevel` outside 1..20.
`InvalidCost`	No positive `BaseCost` and no `CostForLevel`.
`InvalidModule`	Empty plugin guid.

Built-in node ids

Stable, and none of them contains a dot - which is exactly why your ids must. Useful for gating.

Id	Name	Tab	Levels
`walk`	Walking Speed	You	5
`sprint`	Sprint Speed	You	5
`reach`	Long Reach	You	4
`push`	Push Through	You	4
`cashier`	Fast Cashier	Staff	5
`fullday`	Full Day Shift	Staff	1
`training`	Staff Training	Staff	1 soon
`mv_cashier`	Cashier Legs	Staff	5 soon
`mv_restocker`	Restocker Legs	Staff	5 soon
`mv_unloader`	Unloader Legs	Staff	5 soon
`mv_baker`	Baker Legs	Staff	5 soon
`mv_butcher`	Butcher Legs	Staff	5 soon
`mv_seafood`	Seafood Legs	Staff	5 soon

The ones marked soon are drawn and unbuyable. GetLevel returns 0 for them and will keep doing so until they ship - do not gate anything on them.

Limits at a glance

Limit	Value
Nodes per plugin	64
Levels per node	1 - 20
Id length	3 - 64 characters
Sub-tab label	18 characters
Sub-tabs per page	5, then arrows
Kept lines per save slot	4096
`IsUnlocked` cache	0.25 s
Sell-back rate	50% by default; a registered node can declare 0..1 via `SellBackRate`

Differences from the Tech Tree API

The surface is the same, name for name. What differs is the platform and a few numbers:

	Tech Tree	Mega Tree
Namespace	`TechTree.Api`	`MegaTree.Api`
Entry class	`TechTreeApi`	`MegaTreeApi`
Module type	`TechTreeModule`	`MegaTreeModule`
Reserved prefixes	`techtree.` `tt.`	`megatree.` `mt.`
Default sell-back	60%	50%
`Apply` period	~2 s	~0.5 s
Locale argument	BCP-47 (`pt-BR`)	BCP-47 or the game's name (`Portuguese`)
Plugin base	`BasePlugin` / `Load()`	`BaseUnityPlugin` / `Awake()`