Class: rlEngine

rlEngine

new rlEngine(containerId, name, debug, width, height, glContextAttributesopt, useOwnTimeropt) → {rlEngine}

Instantiate an object for easily handling an application/game main loop(gathering input and performing logic state and view updates at regular intervals).

An engine will also provide two Canvas elements along with a webgl and a 2d context, ready-to-use in view updates.

The canvas elements are layered in a way that the 2d canvas will be rendered on top of the webgl canvas.

The 2d canvas will also be used by the engine to display debug information (if enabled).

By default, the engine will instantiate and handle a timer running in a separate thread, so that logic updates can be performed even when the engine is not in the active browser-tab.

An engine starts in Paused state to allow setting the onInputEvent, onUpdateLogic and onUpdateViews properties before calling togglePause to start it.

Parameters:
Name Type Attributes Default Description
containerId string

the DOM id of an Element into which to insert the engines views
name string

the name of the engine as it appears in debug messages, if debug is enabled
debug boolean

set to true to enable debug messages and debug info to be displayed on view updates
width number

the width of the engines views in pixels
height number

the height of the engines views in pixels
glContextAttributes WebGLContextAttributes <optional>

WebGLContextAttributes
useOwnTimer boolean <optional>
 true

set to false to prevent the engine from instantiating and managing its own logic update timer
Returns:
Type
rlEngine

Members

onInputEvent :rlEngine~callbackOnInputEvent

Type:

onUpdateLogic :rlEngine~callbackOnUpdateLogic

Type:

onUpdateViews :rlEngine~callbackOnUpdateViews

Type:

Methods

changeLUPS(newLUPSTarget)

Change the desired number of logic updates per second to perform. (Does not apply if the engine was prevented from managing its own timer at instantiation time.)

Parameters:
Name Type Description
newLUPSTarget number

the desired number of logic updates per second

forceUpdateLogic()

Force a single logic update (even if the engine is in Paused state).

forceUpdateViews()

Force a single views update.

getG2D() → {CanvasRenderingContext2D|null}

Get the 2D rendering context which was instantiated at construction time.

See:
Returns:

the 2D rendering context or null if none is available

Type
CanvasRenderingContext2D | null

getGL() → {WebGLRenderingContext|null}

Get the webgl rendering context which was instantiated at construction time.

See:
Returns:

the webgl rendering context or null if none is available

Type
WebGLRenderingContext | null

getInputState() → {rlInputEvent.mouseKeyboardEvent}

Get the current mouse and keyboard input state (as known by the last processed input event).

Returns:
Type
rlInputEvent.mouseKeyboardEvent

isPaused() → {boolean}

Get the Paused state.

Returns:
Type
boolean

manualTick()

Provided to be called by any external timer on tick (does nothing if engine is in Paused state). (Meant to be use by multiple engine instances sharing the same external timer.)

setCursorImage(newImage, cax, cay)

Set the image to use for rendering the mouse cursor while it is within the engines view area.
e.g.: myEngine.setCursorImage(rlCursors.getDefaultCursorImage(), 0, 0); to set it back to the built-in default cursor.

Parameters:
Name Type Description
newImage HTMLImageElement | string

the image to display as the mouse cursor (or a string to set the cursor CSS property of the engines views)
cax number

cursor active x: horizontal-axis position of the cursor images active pixel
cay number

cursor active y: vertical-axis position of the cursor images active pixel
See:

toggleDebug()

Toggle the debug state.

togglePause()

Toggle the Paused state. As long as an engine is paused, it will not call logic updates.
It will still gather input events and call view updates.

Type Definitions

callbackOnInputEvent(previousEvent, currentEvent)

Function signature for callbacks to use with onInputEvent.

Parameters:
Name Type Description
previousEvent rlInputEvent.mouseKeyboardEvent
currentEvent rlInputEvent.mouseKeyboardEvent

callbackOnUpdateLogic(LUTick)

Function signature for callbacks to use with onUpdateLogic.

Parameters:
Name Type Description
LUTick number

the logic update tick (increases by 1 with each logic update)

callbackOnUpdateViews(GL, G2D, time)

Function signature for callbacks to use with onUpdateViews.

Parameters:
Name Type Description
GL WebGLRenderingContext

a WebGLRenderingContext for the lower layer of the engines view
G2D CanvasRenderingContext2D

a CanvasRenderingContext2D for the upper layer of the engines view
time DOMTimeStamp | DOMHighResTimeStamp

a timestamp as provided by requestAnimationFrame