Mouse

import "lumen:mouse"

The mouse module reports where the pointer is, which buttons are down, and controls the cursor.

Position

function draw() {
  position = mouse.getPosition()

  canvas.setColor(color.white)
  canvas.filledCircle(position[0], position[1], 8)
}

getPosition() returns [x, y]; mouse.x and mouse.y are the same two numbers read one at a time.

Positions are in the same coordinate space the game draws in. With a logical size set, they arrive already scaled into it, so nothing in your game has to know that scaling is happening.

getWorldPosition() maps the pointer back through the current transform, which is how a game finds what the player clicked on while a camera is active:

function draw() {
  canvas.push()
  canvas.translate(-camera.x, -camera.y)

  world = mouse.getWorldPosition()
  hovered = tileAt(world[0], world[1])

  canvas.pop()
}

Buttons

Buttons are named 'left', 'middle', 'right', 'x1', and 'x2'.

Method	What it reports
isButtonDown(button)	The button is held down right now.
isButtonUp(button)	The button is not held down.
wasButtonPressed(button)	The button went down this frame.
wasButtonReleased(button)	The button came up this frame.

The same held-versus-pressed distinction applies as on the keyboard: use isButtonDown for dragging, wasButtonPressed for clicking.

function update(dt) {
  if (mouse.wasButtonPressed('left')) {
    select(mouse.getWorldPosition())
  }
}

The mousepressed, mousereleased, mousemoved, and wheelmoved callbacks carry the same events with their coordinates attached, including a click count that distinguishes a double-click.

Methods

Method	What it does
getPosition()	[x, y] of the pointer.
setPosition(x, y)	Warps the pointer.
getWorldPosition()	[x, y] mapped back through the current transform.
showCursor() / hideCursor()	Shows or hides the system cursor.
isVisible()	Whether the cursor is showing.
isButtonDown(button) / isButtonUp(button)	Button state.
wasButtonPressed(button) / wasButtonReleased(button)	Button edges.
setRelativeMode(bool)	Hides the cursor and reports movement instead of position — for a first-person or free-look camera.
setGrabbed(bool)	Confines the cursor to the window.

Properties

Property	Value
mouse.x	Pointer x.
mouse.y	Pointer y.
mouse.wheel	Vertical wheel movement this frame.
mouse.wheelX	Horizontal wheel movement this frame.

function update(dt) {
  if (mouse.wheel != 0) {
    camera.zoom = math.clamp(camera.zoom + mouse.wheel * 0.1, 0.5, 4)
  }
}