Timer

The timer module reports frame timing: how long the last frame took, how many frames a second the game is managing, and how long it has been running.

Frame Time

timer.delta is the same value handed to update(dt) — the seconds the previous frame took. Multiplying movement by it keeps a game running at the same speed on any machine.

function update(dt) {
  // dt and timer.delta are the same number
  game.x = game.x + 180 * dt
}

Reading it from timer is useful in a function that isn't update() and wasn't handed dt.

Methods

Method	What it returns
getDelta()	Seconds the previous frame took.
getFps()	Frames per second, as measured.
getTime()	Seconds since the game started.
sleep(seconds)	Blocks for that long.

getDelta(), getFps(), and getTime() are the method forms of the properties below and return the same values.

timer.sleep() stalls the whole game — the loop does not run, nothing draws, and input is not read. It exists for scripts and tools rather than gameplay. To make something happen later in a game, count dt down instead.

Properties

Property	Value
timer.delta	Seconds the previous frame took.
timer.averageDelta	Frame time averaged over recent frames — steadier than delta for display.
timer.fps	Frames per second.
timer.time	Seconds since the game started.
timer.frame	How many frames have been drawn.

Showing a Frame Counter

function draw() {
  canvas.setColor(color.white)
  canvas.print('FPS: ' + timer.fps.toString(), 10, 10)
}

Use averageDelta rather than delta for anything a player looks at: a per-frame number flickers too much to read.

Timers Without sleep

Counting down in update() is how a game waits.

game = { cooldown: 0 }

function update(dt) {
  if (game.cooldown > 0) {
    game.cooldown = game.cooldown - dt
  }

  if (keyboard.wasPressed('space')) {
    if (game.cooldown <= 0) {
      fire()

      game.cooldown = 0.4 // seconds until the next shot
    }
  }
}