Engine

promise Promise<any>

Returns

• The same promise

async function gameInit() { level = await engineAddLoad(fetchJSON('level.json')); }

update PluginCallback optional

render PluginCallback optional

glContextLost PluginCallback optional

glContextRestored PluginCallback optional

preRender PluginCallback optional

Called after the canvas is cleared and before gameRender

updatePost PluginCallback optional

Called after the objects update each tick, before gameUpdatePost, paused included, for what follows an object, like a camera

gameInit GameInitCallback optional

Called once after the engine starts up, can be async for loading

gameUpdate GameCallback optional

Called every frame before objects are updated (60fps), use for game logic

gameUpdatePost GameCallback optional

Called after physics and objects are updated, even when paused, use for UI updates

gameRender GameCallback optional

Called before objects are rendered, use for drawing backgrounds/world elements

gameRenderPost GameCallback optional

Called after objects are rendered, use for drawing UI/overlays

imageSources Array<string>|string optional, default []

List of image file paths to preload (e.g., ['player.png', 'tiles.png']), or one path

rootElement HTMLElement optional

Root DOM element to attach canvas to, defaults to document.body; it is styled for a game (no scroll bars or selection, touch-action none) where its own inline style does not say otherwise, and the canvas centers inside it, but the canvas is still sized from the window, so set canvasFixedSize or canvasMaxSize to fit a smaller element

Returns

• Done when the images have loaded and gameInit has run

// Basic engine startup
engineInit(
  ()=> { LOG('Game initialized!'); },  // gameInit
  ()=> { updateGameLogic(); },         // gameUpdate
  ()=> { updateUI(); },                // gameUpdatePost
  ()=> { drawBackground(); },          // gameRender
  ()=> { drawHUD(); },                 // gameRenderPost
  ['tiles.png', 'tilesLevel.png']       // images to load
);

pos Vector2 optional

Center of test area, or undefined for all objects

size Vector2|number optional

Diameter of a circle if a number, full size of a rectangle if a Vector2

callbackFunction ObjectCallbackFunction optional

Calls this function on every object that passes the test, needed (marked optional only because the area before it is)

objects Array<EngineObject> optional, default engineObjects

List of objects to check

testCenters boolean optional, default false

Test only each object's center, see engineObjectsCollect

pos Vector2 optional

Center of test area, or undefined for all objects

size Vector2|number optional

Diameter of a circle if a number, full size of a rectangle if a Vector2, left out or 0 the objects that overlap the point at pos

objects Array<EngineObject> optional, default engineObjects

List of objects to check

testCenters boolean optional, default false

Test only each object's center, a little faster, and ignores object sizes

Returns

• List of collected objects

immediate boolean optional, default true

true removes attached effects like particle emitters at once, false lets them finish first

start Vector2

end Vector2

objects Array<EngineObject> optional, default engineObjects

List of objects to check

Returns

• List of objects hit

frames number optional, default 1

frames of 1/60 of a second to advance, max 36000; timeScale sets how many fixed updates they run, as in the normal loop, one each at timeScale 1

setHeadlessMode(true);
setEngineManualStep(true);
await engineInit(gameInit, gameUpdate, gameUpdatePost, gameRender, gameRenderPost);
engineStep(600); // 600 updates of 1/60 second; the first is at time 0, so time is then 599/60, with
                 // setEngineVariableStep(true) the first is at 1/60 and time is 600/60

isPaused boolean optional, default true

progress number

The part of the loads done, 0 to 1

object EngineObject