LuaScript/Callbacks

The Lua scripting environment contains several callbacks which the game will call at certain points. You can define these callback functions to run code.

init(is_sandbox)

A callback that runs once on the initial load of the LuaScript.

First argument is_sandbox can be used to check whether the level is played from the sandbox or not (true/false).

Example:

function init(is_sandbox)
    game:message("is_sandbox: " .. (is_sandbox and "yes" or "no"))
end

step(count)

A callback that runs on every game step.

First argument count is an incrementing counter that increments by one for every step.

function step(count)
    game:show_numfeed(count)
end

on_event(id)

A callback that gets called whenever an event occurs.

First argument id is the event ID.

Example:

function on_event(id)
    if id == EVENT_ENEMY_ID then
        game:message("Enemy robot just died!")
    end
end

on_input(type, data)

A callback that gets called when a key is pressed.

The first argument is the input type ID. The following IDs exist, which have respective constants defined:

ID	Constant
4	INPUT_KEY_DOWN
8	INPUT_KEY_UP
16	INPUT_POINTER_DOWN
32	INPUT_POINTER_UP

The second argument is a table containing some data which depends on the input ID.

For keys:

One key called keycode which contains a keycode of the pressed key. While TMS' keycodes include more than those below, these are the most common keys that also have helper constants provided:

ID	Constant
4	KEY_A
5	KEY_B
6	KEY_C
7	KEY_D
8	KEY_E
9	KEY_F
10	KEY_G
11	KEY_H
12	KEY_I
13	KEY_J
14	KEY_K
15	KEY_L
16	KEY_M
17	KEY_N
18	KEY_O
19	KEY_P
20	KEY_Q
21	KEY_R
22	KEY_S
23	KEY_T
24	KEY_U
25	KEY_V
26	KEY_W
27	KEY_X
28	KEY_Y
29	KEY_Z
30	KEY_1
31	KEY_2
32	KEY_3
33	KEY_4
34	KEY_5
35	KEY_6
36	KEY_7
37	KEY_8
38	KEY_9
39	KEY_0
40	KEY_ENTER
41	KEY_ESC
42	KEY_BACKSPACE
43	KEY_TAB
44	KEY_SPACE
79	KEY_RIGHT
80	KEY_LEFT
81	KEY_DOWN
82	KEY_UP

For pointer input (i.e. mouse click, finger press):

A table with three keys is provided:

• pid: The ID of the pointer.
  • On desktop the primary mouse button is mapped to 0, secondary mouse button is mapped to 1 and the scrollwheel button is mapped to 2.
  • On mobile each finger touching the screen is given an increasing ID.
• x: X position where the input happened in the native windows resolution and with origin in the bottom left.
• y: Y position where the input happened in the native windows resolution and with origin in the bottom left.

Example:

function on_input(id, data)
    if id == INPUT_KEY_DOWN then
        if data.keycode == KEY_F then
            game:message("You just paid your respects.")
        end
    elseif id == INPUT_POINTER_DOWN then
        game:message("You pressed the screen at ("..data.x..","..data.y..")!")
    end
end

on_response(response, prompt_id)

A callback that gets called when a prompt opened with game:prompt() is closed with a button being pressed.

Example:

function on_response(response, prompt_id)
    game:message('The response I got from prompt ' .. prompt_id .. ' was ' .. response)
end

on_halt()

Called when the script is halted due to reaching the execution time limit.