Cartridge API

The complete API available to every cartridge. Functions are deterministic unless noted.

Lifecycle

init

export function init(): void

Run once when the cartridge starts.

update

export function update(): void

Run at 60 Hz to update game state and read input.

draw

export function draw(): void

Run after every update to emit drawing commands.

Drawing

clear

clear(color = 0)

Fill the canvas with one palette color.

pixel

pixel(x, y, color)

Draw one pixel.

line

line(x0, y0, x1, y1, color)

Draw a line between two points.

rect

rect(x, y, width, height, color, fill = false)

Draw an outlined or filled rectangle.

circle

circle(x, y, radius, color, fill = false)

Draw an outlined or filled circle.

text

text(value, x, y, color)

Draw text with the built-in bitmap font.

sprite

sprite(pixels, width, height, x, y, transparent = 0)

Draw row-major indexed sprite pixels.

map

map(tiles, columns, tileWidth, tileHeight, spritesheet, sheetColumns, x = 0, y = 0, transparent = 0)

Draw a row-major tile map from an indexed spritesheet.

Input

button

button(input)

Check whether an input is currently held.

buttonPressed

buttonPressed(input)

Check whether an input was pressed this update.

World and camera

camera

camera(x = 0, y = 0)

Offset subsequent drawing coordinates; call without arguments to reset.

Deterministic utilities

seed

seed(value = 1)

Reset the deterministic random sequence.

random

random(min = 0, max = 1)

Return the next deterministic random number.

overlap

overlap(ax, ay, aw, ah, bx, by, bw, bh)

Check two axis-aligned rectangles for overlap.

pointInRect

pointInRect(px, py, x, y, width, height)

Check whether a point is inside a rectangle.

frame

frame()

Return the current deterministic update number.

every

every(interval, offset = 0)

Return true on a repeating frame interval.

after

after(frames)

Return true after a frame threshold.

Audio

tone

tone(frequency, duration = 100, volume = 0.15, wave = "square")

Play one bounded cartridge tone.

sfx

sfx(notes, step = 80, volume = 0.15, wave = "square")

Play up to 32 frequencies as a short effect.