sm64ex-coop/docs/lua/guides/hooks.md

⏪ Lua Reference

Hooks

Hooks are a way for SM64 to trigger Lua code, whereas the functions listed in functions allow Lua to trigger SM64 code.

Supported Hooks

• hook_behavior
• hook_chat_command
• hook_event
• hook_mario_action
• hook_on_sync_table_change

hook_behavior

hook_behavior() allows Lua mods to override existing behaviors or create new ones.

Parameters

Field	Type	Notes
behaviorId	enum BehaviorId	Set to nil to create a new behavior
objectList	enum ObjectList
replaceBehavior	bool	Prevents the original behavior code from running
initFunction	Lua Function (Object obj)	Runs once per object
loopFunction	Lua Function (Object obj)	Runs once per frame per object
behaviorName	string	Optional, name to give to the behavior

Returns

• enum BehaviorId

Lua Example

function bhv_example_init(obj)
    obj.oFlags = OBJ_FLAG_UPDATE_GFX_POS_AND_ANGLE
    network_init_object(obj, true, nil)
end

function bhv_example_loop(obj)
    obj.oPosY = obj.oPosY + 1
end

id_bhvExample = hook_behavior(nil, OBJ_LIST_DEFAULT, true, bhv_example_init, bhv_example_loop, "bhvExample")

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hook_chat_command

hook_chat_command() allows Lua mods to react and respond to chat commands. Chat commands start with the / character. The function the mod passes to the hook should return true when the command was valid and false otherwise.

Parameters

Field	Type
command	string
description	string
func	Lua Function (string message) -> bool

Lua Example

function on_test_command(msg)
    if msg == 'on' then
        djui_chat_message_create('Test: enabled')
        return true
    elseif msg == 'off' then
        djui_chat_message_create('Test: disabled')
        return true
    end
    return false
end

hook_chat_command('test', "[on|off] turn test on or off", on_hide_and_seek_command)

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hook_event

The lua functions sent to hook_event() will be automatically called by SM64 when certain events occur.

Hook Event Types

Type	Description	Parameters
HOOK_UPDATE	Called once per frame	None
HOOK_MARIO_UPDATE	Called once per player per frame at the end of a mario update	MarioState mario
HOOK_BEFORE_MARIO_UPDATE	Called once per player per frame at the beginning of a mario update	MarioState mario
HOOK_ON_SET_MARIO_ACTION	Called every time a player's current action is changed	MarioState mario
HOOK_BEFORE_PHYS_STEP	Called once per player per frame before physics code is run, return an integer to cancel it with your own step result	MarioState mario, integer stepType
HOOK_ALLOW_PVP_ATTACK	Called when one player attacks another, return true to allow the attack	MarioState attacker, MarioState victim
HOOK_ON_PVP_ATTACK	Called when one player attacks another	MarioState attacker, MarioState victim
HOOK_ON_PLAYER_CONNECTED	Called when a player connects	MarioState connector
HOOK_ON_PLAYER_DISCONNECTED	Called when a player disconnects	MarioState disconnector
HOOK_ON_HUD_RENDER	Called when the HUD is being rendered	None
HOOK_ALLOW_INTERACT	Called before mario interacts with an object, return true to allow the interaction	MarioState interactor, Object interactee, enum InteractionType interactType
HOOK_ON_INTERACT	Called when mario interacts with an object	MarioState interactor, Object interactee, enum InteractionType interactType, bool interactValue
HOOK_ON_LEVEL_INIT	Called when the level is initialized	None
HOOK_ON_WARP	Called when the local player warps	None
HOOK_ON_SYNC_VALID	Called when the current area is synchronized	None
HOOK_ON_OBJECT_UNLOAD	Called when any object is unloaded	Object unloadedObject
HOOK_ON_SYNC_OBJECT_UNLOAD	Called when any networked object is unloaded	Object unloadedObject
HOOK_ON_PAUSE_EXIT	Called when the local player exits through the pause screen, return false to prevent the exit	boolean usedExitToCastle
HOOK_GET_STAR_COLLECTION_DIALOG	Called when the local player collects a star, return a DialogId to show a message	None
HOOK_ON_SET_CAMERA_MODE	Called when the camera mode gets set, return false to prevent the camera mode from being set	Camera, integer mode, integer frames
HOOK_ON_OBJECT_RENDER	Called right before an object is rendered. Note: You must set the hookRender field of the object to a non-zero value	Object renderedObj
HOOK_ON_DEATH	Called when the local player dies, return false to prevent normal death sequence	MarioState localMario
HOOK_ON_PACKET_RECEIVE	Called when the mod receives a packet that used network_send() or network_send_to()	table dataTable
HOOK_USE_ACT_SELECT	Called when the level changes, return true to show act selection screen and false otherwise	integer levelNum
HOOK_ON_CHANGE_CAMERA_ANGLE	Called when the player changes the camera mode to Lakitu cam or Mario cam, return false to prevent the change.	integer mode
HOOK_ON_SCREEN_TRANSITION	Called when the game is about to play a transition, return false to prevent the transition from playing.	integer type
HOOK_ALLOW_HAZARD_SURFACE	Called once per player per frame. Return false to prevent the player from being affected by lava or quicksand.	MarioState mario, integer hazardType
HOOK_ON_CHAT_MESSAGE	Called when a chat message gets sent. Return false to prevent the message from being sent.	MarioState messageSender, string messageSent
HOOK_OBJECT_SET_MODEL	Called when a behavior changes models. Also runs when a behavior spawns.	Object obj, integer modelID
HOOK_CHARACTER_SOUND	Called when mario retrieves a character sound to play, return a character sound or 0 to override it.	MarioState mario, enum CharacterSound characterSound
HOOK_JOINED_GAME	Called when the local player finishes the join process (if the player isn't the host)	None
HOOK_BEFORE_SET_MARIO_ACTION	Called before Mario's action changes. Return an action to change the incoming action or 1 to cancel the action change.	MarioState mario, integer incomingAction
HOOK_ON_OBJECT_ANIM_UPDATE	Called when an object's animation is updated.	Object objNode
HOOK_ON_DIALOG	Called when a dialog appears. Return false to prevent it from appearing.	integer dialogId
HOOK_MIRROR_MARIO_RENDER	Called when a Mirror Mario is rendered.	GraphNodeObject mirrorMario

Parameters

Field	Type
hook_event_type	HookEventType
func	Lua Function (...)

Lua Example

The following example will print out a message 16 times per frame (once for every possible player).

function mario_update(m)
    print('Mario update was called for player index ', m.playerIndex)
end

hook_event(HOOK_MARIO_UPDATE, mario_update)

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hook_exclamation_box

Activated when an exclamation box breaks, allowing mods to take control over exclamation boxes.

• readFunction is called after the exclamation box breaks, allowing mods to read the object that spawned.
  • No return value is necessary.
• writeFunction is called when the exclamation box breaks, allowing mods to override the spawned object.
  • Returning the spawned object is highly recommended as it prevents spawning both the vanilla and new object at the same time. It also allows readFunction to function properly.

Parameters

Field	Type
readFunction	Lua Function (Object)
writeFunction	Lua Function (Object): Object

Lua Example

local objects_to_spawn = {
    [0] = {id_bhvGoomba, E_MODEL_GOOMBA},
    [1] = {id_bhvKoopa, E_MODEL_KOOPA_WITH_SHELL},
    [2] = {id_bhvTenCoinsSpawn, E_MODEL_NONE},
    [3] = {id_bhvChainChomp, E_MODEL_CHAIN_CHOMP},
    [4] = {id_bhvHeaveHo, E_MODEL_HEAVE_HO},
    [5] = {id_bhvWingCap, E_MODEL_MARIOS_WING_CAP},
    [6] = {id_bhvKoopaShell, E_MODEL_KOOPA_SHELL},
    [7] = {id_bhvBoo, E_MODEL_BOO},
}

local function readFunction(obj)
    if obj_has_behavior_id(obj, id_bhvFlame) ~= 0 then
        print("FIREEEEEEEEE")
    end
end

---@param box Object
local function writeFunction(box)
    local spawn_object = objects_to_spawn[box.oBehParams2ndByte]
    return spawn_sync_object(spawn_object[1], spawn_object[2], box.oPosX, box.oPosY, box.oPosZ, nil)
end

hook_exclamation_box(readFunction, writeFunction)

hook_mario_action

hook_mario_action() allows Lua mods to create new actions or override existing ones.

Parameters

Field	Type
action_id	integer
func	Table with entries for Action Hook Types of Lua Function (MarioState m)
interaction_type	enum InteractionFlag

Action Hook Types

Type	Description	Returns
every_frame	Main action code, called once per frame	true if action cancelled, else false
gravity	Called inside apply_gravity when in action	Unused

Lua Example

ACT_WALL_SLIDE = (0x0BF | ACT_FLAG_AIR | ACT_FLAG_MOVING | ACT_FLAG_ALLOW_VERTICAL_WIND_ACTION)

function act_wall_slide(m)
    if (m.input & INPUT_A_PRESSED) ~= 0 then
        local rc = set_mario_action(m, ACT_TRIPLE_JUMP, 0)
        m.vel.y = 72.0

        if m.forwardVel < 20.0 then
            m.forwardVel = 20.0
        end
        m.wallKickTimer = 0
        return rc
    end

    -- attempt to stick to the wall a bit. if it's 0, sometimes you'll get kicked off of slightly sloped walls
    mario_set_forward_vel(m, -1.0)

    m.particleFlags = m.particleFlags | PARTICLE_DUST

    play_sound(SOUND_MOVING_TERRAIN_SLIDE + m.terrainSoundAddend, m.marioObj.header.gfx.cameraToObject)
    set_mario_animation(m, MARIO_ANIM_START_WALLKICK)

    if perform_air_step(m, 0) == AIR_STEP_LANDED then
        mario_set_forward_vel(m, 0.0)
        if check_fall_damage_or_get_stuck(m, ACT_HARD_BACKWARD_GROUND_KB) == 0 then
            return set_mario_action(m, ACT_FREEFALL_LAND, 0)
        end
    end

    m.actionTimer = m.actionTimer + 1
    if m.wall == nil and m.actionTimer > 2 then
        mario_set_forward_vel(m, 0.0)
        return set_mario_action(m, ACT_FREEFALL, 0)
    end

    return 0
end

function act_wall_slide_gravity(m)
    m.vel.y = m.vel.y - 2

    if m.vel.y < -15 then
        m.vel.y = -15
    end
end

function mario_on_set_action(m)
    -- wall slide
    if m.action == ACT_SOFT_BONK then
        m.faceAngle.y = m.faceAngle.y + 0x8000
        set_mario_action(m, ACT_WALL_SLIDE, 0)
    end
end

hook_event(HOOK_ON_SET_MARIO_ACTION, mario_on_set_action)
hook_mario_action(ACT_WALL_SLIDE, { every_frame = act_wall_slide, gravity = act_wall_slide_gravity } )

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hook_on_sync_table_change

hook_on_sync_table_change() allows Lua mods to react to sync table changes.

• syncTable parameter must be a sync table, e.g. gGlobalSyncTable, gPlayerSyncTable[], or one of their child tables.
• field parameter must be one of the fields in the SyncTable.
• tag parameter can be any type, and is automatically passed to the callback.
• func parameter must be a function with three parameters: tag, oldVal, and newVal.
  • tag will be the same tag passed into hook_on_sync_table_change().
  • oldVal will be the value before it was set.
  • newVal will be the value that it was set to.

Parameters

Field	Type
syncTable	SyncTable
field	value
tag	value
func	Lua Function (value tag, value oldValue, value newValue)

Lua Example

function on_testing_field_changed(tag, oldVal, newVal)
    print('testingField changed:', tag, ',', oldVal, '->', newVal)
end

hook_on_sync_table_change(gGlobalSyncTable, 'testingField', 'tag', on_testing_field_changed)

-- now when testingField is set, either locally or over the network, on_testing_field_changed() will be called
gGlobalSyncTable.testingField = 'hello'

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