Game Boulder

Game Boulder logo

Game Boulder is a game engine built in JavaScript. I modeled this around the language paradigms from older versions of GameMaker. This is still pretty early in it’s life, but it’s already fairly stable and competent as a game making tool.

Download

You can download Game Boulder or browse the source code on Github.

Let’s play some demos!

Reference

This table contains every object and function you need to get started with Game Boulder. There’s more information on the Github page.

Type Property Description
EngineResource GameEngine(String canvasSelector || Object HTMLCanvasElement, fps=24) ID selector for canvas, game FPS
array GameEngine.rooms Array of all rooms in the game, accessible to the engine.
array GameEngine.sprites Array of all registered sprites.
array GameEngine.resources Array of all registered files
array GameEngine.objects Array of all registered objects.
array GameEngine.sounds Array of all registered sounds (EngineResources, not files)
array GameEngine.tiles Array of all registered tiles
array GameEngine.backgrounds Array of all registered backgrounds
function GameEngine.generateID Generates a new unique ID
function GameEngine.checkKey(String KeyEvent.type) Function to check if key is currently being held
function GameEngine.checkMouse(Number mouseButton) Function to check if mouse button is currently being held
function GameEngine.getEngineResources(Number any=-1 || String name || Number ID) Returns EngineResources across all categories. If a name or ID is specified, only resources matching that name or ID will be returned.
function GameEngine.getSprite(Number ID=-1 || String name || EngineResource Sprite) Returns a registered Sprite resource from a name, ID, or object. Note that Instances created using Instance() will not be retrieved.
function GameEngine.getObject(Number ID=-1 || String name || EngineResource GameObject) Returns a registered Object resource from a name, ID, or object. Note that Instances created using Instance() will not be retrieved.
function GameEngine.addRoom(EngineResource Room) Function to add rooms to game registry. This is done automatically when a room is created.
function GameEngine.getRoom(Number ID || String roomName) Get a room object from either an ID or name
function GameEngine.getCurrentRoom() Gets the currently active game room
function GameEngine.setCurrentRoom(Number ID || String roomName) Switches game to a room
function GameEngine.importTiles(JSON tileData) Import tileset from JSON. Useful for designing rooms in-game
function GameEngine.begin() Start the game loop
function GameEngine.getIntersecting(x1,y1,x2,y2) Get if two rectangles are intersecting based on their coordinates
function GameEngine.mDistance(Number x1, Number y1, Number x2, Number y2) Returns Manhattan distance given two sets of coordinates.
function GameEngine.distance(Number x1, Number y1, Number x2, Number y2, Boolean precise=true) Returns Pythagorean distance given two sets of coordinates, or, if precise is false, return Manhattan distance.
function GameEngine.getPointDirection(Number direction, Number distance) Returns an array of the X and Y coordinates given a direction and distance (ie, direction 270 and distance 1 yields Array [0,1]).
function GameEngine.getPointDir(Number direction, Number distance) Alias of GameEngine.getPointDirection
function GameEngine.getDirectionFromPoints(Number x1, Number y1, Number x2, Number y2) Returns the angle in degrees from coordinate x1,y1 to coordinate x2,y2.
function GameEngine.choose(Array toChooseFrom) Chooses a random element from an array.
function GameEngine.random(Number min=0, Number max=1) Returns a random number between min and max.
function GameEngine.irandom(Number min=0, Number max=1) Returns a random integer between min and max.
function GameEngine.degToRad(Number degrees) Converts the provided degrees into radians.
function GameEngine.radToDeg(Number radians) Converts the provided radians into degrees.
object GameEngine.draw Collection of drawing functions to draw somewhere in a room, based on the view position, not the canvas position.
function GameEngine.draw.rect(Number x, Number y, Boolean fill=false, Number color=-1 || String color=””) Draws a filled or unfilled rectangle at a given point in the room. Not supplying a color will draw it at whatever the current canvas context fill or stroke color is.
function GameEngine.draw.text(String text, Number x, Number y, Boolean fill=false, Number color=-1 || String color=””) Draws a filled or unfilled text at a given point in the room. Not supplying a color will draw it at whatever the current canvas context fill or stroke color is.
function GameEngine.draw.arc(Number x, Number y, Number startAngle, Number endAngle, Boolean counterClockWise=false, Number color=-1 || String color=””) Draws an arc at a given point in the room. Note that angles are in degrees, not radians. Not supplying a color will draw it at whatever the current canvas context fill or stroke color is.
function GameEngine.draw.ellipse(Number x, Number y, Number radiusX, Number radiusY, Number rotation, Number startAngle, Number endAngle, Boolean counterClockWise=false, Number color=-1 || String color=””) Draws an ellipse at a given point in the room. Note that angles are in degrees, not radians. Not supplying a color will draw it at whatever the current canvas context fill or stroke color is.
function GameEngine.draw.image(HTMLImageElement image, Number dx, Number dy) || (HTMLImageElement image, Number dx, Number dy, Number dWidth, Number dHeight) || (HTMLImageElement image, Number sx, Number sy, Number sWidth, Number sHeight, Number dx, Number dy, Number dWidth, Number dHeight) Draws an image at a given point in the room. See the MDN for a more detailed reference on the arguments.
function GameEngine.draw.line(Array coordinates[Array [Number x, Number y],…], Number width=1, Number color=1 || String color=””) Draws a line or lines between all coordinates provided in the coordinates argument. Not supplying a color will draw it at whatever the current canvas context fill or stroke color is.
number GameEngine.currentRoom Array index of current active game room.
number GameEngine.fps Framerate at which the game will run
object GameEngine.debug Debug flags
object GameEngine.engine Object containing utilities and canvas data
object GameEngine.engine.ctx Reference to 2D context. Can be used to draw to the canvas natively.
object GameEngine.engine.importResource(String fileName, forceNewResource=false) Adds a file resource to the game’s resource registry. This is mainly called internally.
string GameEngine.status Current gamestate
EngineResource GameObject(String name, Number x=0, Number y=0, EngineResource Sprite=-1, Function onstep=-1, Function ondraw=-1, Boolean visible=true, Boolean active=true, Array collisionBox=false || Boolean collisionBox=false, Number depth=0) Building block of game interactivity.
array GameObject.collisionBox Coordinates to use when checking for collisions. Defaults to sprite width/height or 16×16 if no sprite is specified.
collisionBox entries are [x,y,width,height].
boolean GameObject.visible Whether the object should draw a sprite and perform its draw event
function GameObject.onstep() Custom event to execute every game step (frame)
function GameObject.getCoordinates(Boolean object=true) Returns an object with the values of this objects x1, x2, y1, and y2, based on its location and collision box.
function GameObject.getCoords(Boolean object=true) Alias of GameObject.getCoordinates.
function GameObject.getCollisions(solidOnly=false, offsetX = 0, offsetY = 0) Returns an array of all objects this object is currently overlapping with. Solid only specifies whether to check for collisions with all objects, or just ones marked solid. offsetX and offsetY indicate offsets from the current location of the collisionBox.
function GameObject.wrap(wrapX=true,wrapY=true) Checks to see if an object is outside of the room, and if it is, will move the object to the other side. Specifying wrapX and wrapY will determine which axes the object should wrap on.
function GameObject.ondraw() Custom event to execute every game draw (frame)
function GameObject.ondestroy() Custom event to execute when the GameObject is destroyed via destroy()
function GameObject.onkeypress(KeyboardEvent ev) Custom event to handle key presses. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event.
function GameObject.onkeyup(KeyboardEvent ev) Custom event to handle key releases. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event.
function GameObject.onkeydown(KeyboardEvent ev) Custom event to handle key downs. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event.
function GameObject.onmousedown(KeyboardEvent ev, Boolean local) Custom event to handle mouse presses. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event. The local argument indicates whether the mouse event occured over the objects collision box.
function GameObject.onmouseup(KeyboardEvent ev, Boolean local) Custom event to handle mouse releases. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event. The local argument indicates whether the mouse event occured over the objects collision box.
function GameObject.onmousemove(KeyboardEvent ev, Boolean local) Custom event to handle mouse movement. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event. The local argument indicates whether the mouse event occured over the objects collision box.
function GameObject.oncontextmenu(KeyboardEvent ev, Boolean local) Custom event to handle right clicks. This recieves input events from native JavaScript event listeners. The first argument provides the data from the event. The local argument indicates whether the mouse event occured over the objects collision box.
function GameObject.generatePath(Number x, Number y, Number gridWidth, number gridHeight) Generate a path to a given location on a certain grid, avoiding solid objects. Note that this is an extremely performance-heavy function and should only be called when needed. Using a larger gridWidth/gridHeight decreases the performance cost, but lowers the path resolution..
function GameObject.pathStep(Number speed=0) Take a step to/towards the next step in the path generated by generatePath(). A speed of 0 will make the object jump to its next coordinate. A non-zero speed will make the object execute moveTowardsPoint() towards its next path coordinate.
function GameObject.moveTowardsPoint(Number x, Number y, Number speed) Move towards given coordinates, ignoring objects in the way
function GameObject.moveInDirection(Number direction, Number speed) Move at a given speed in a given direction (degrees)
function GameObject.moveContactSolid(Number direction, Number maxDistance=-1) Move this GameObject in a given direction until it has come in contact with a solid object. If it does not reach a solid object in less than the maxDistance, it will not move. A maxDistance of -1 will move the object until it finds a solidObject, or until it is outside of the room. Returns false if no solid is contacted.
function GameObject.snapToGrid(Number gridWidth=room.gridWidth, Number gridHeight=room.gridHeight) Snaps the GameObject’s x and y coordinates to a specified grid.
function GameObject.getOutsideRoom() Returns true if the outside of the current room’s bounds.
function GameObject.getOutsideView() Returns true if the outside of the current view’s bounds.
function GameObject.setSprite(String spriteName || Number ID || EngineResource Sprite, Number frameX=-1, Number frameY=-1, Number speed=-1, Number scaleX=-1, Number scaleY=-1) Changes the GameObject’s sprite IF the sprite is different from the object’s current sprite. Specifying -1 for any of the optional arguments will leave the value unchanged for the current sprite.
function GameObject.setDepth(Number z=0) Set the position in the draw order (z-index)
function GameObject.destroy() Remove this object from the current room
function GameObject.deactivate() Prevent this object from performing any of its actions or drawing without removing it from the room.
function GameObject.activate() Reactivate the object
number GameObject.x X coordinate of object in room
number GameObject.y Y coordinate of object in room
number GameObject.sprite EngineResource Sprite to draw at the GameObject’s position in the room
number GameObject.hspeed Horizontal speed
number GameObject.vspeed Vertical speed
number GameObject.friction Friction to apply to object’s movements
number GameObject.gravity Gravity to apply to object
number GameObject.gravityDirection Direction of gravity to apply
number GameObject.fallSpeed The current speed at which an object is falling in the direction of its specified gravity.
number GameObject.terminalVelocity The maximum fallSpeed an object can achieve.
number GameObject.id Internal unique ID
object GameObject.path Path generated by generatePath()
object GameObject.tags Object containing tag data related to the object. Tag data can be used to apply identifying properties to an object.
function GameObject.tags.list() Returns all tags for the current GameObject.
function GameObject.tags.has(String tagName) Checks to see if the GameObject has a specific tag. Returns true if the tag is found, and false if it is not.
function GameObject.tags.get(String tagName) Gets the index of the tag in the GameObjects tag array.
function GameObject.tags.add(String tagName) Adds a tag to the GameObject. Returns false if the tag is already present.
function GameObject.tags.push(String tagName) Alias of GameObject.tags.add
function GameObject.tags.remove(String tagName) Removes a tag from the GameObject. Returns the new list of tags.
string GameObject.name String used to identify the object in a room
EngineResource Instance(String EngineResource.name || Number EngineResource.id || Object EngineResource || Object object Creates a deep copy of an EngineResource. Note that no references are passed to the new object with the exception of HTML resources. For performance reasons, it is recommended that you use the Instance resource sparingly, and instead create instances using constructor functions.
EngineResource Room(String roomName, Number width = 1280, Number height = 720, Number gridX=32, Number gridY=32, Array roomObjects = [], Array tiles=[], EngineResource Background) || String color)
array roomObjects All objects currently in the room
array Room.tiles All tiles currently in the room
function Room.addObject(EngineResource GameObject, Boolean copy=false, sortDepth=true) Adds an object to this room. Specifying that it should be a copy will create a shallow copy of the object. It is recommended you create constructor functions for objects that need instances. sortDepth will cause the room to adjust the depth order according to the new object’s depth. If the object’s depth doesn’t matter, setting sortDepth to false will slightly improve performance.
function Room.getObject(String objectName || Number ID) Get an object in the room given an ID or object name. If there are multiple objects with the name, it will return the first in the room array.
function Room.getObjects(String objectName || String[] objectName) Get an array of instances of an object in the room given an object name, or array of object names.
function Room.getTilesAt(Number x, Number y, Boolean solidOnly = false, Number width = 1, Number height = 1) Get all tiles at a given location
function Room.getObjectsAt(Number x, Number y, Boolean solidOnly = false, Number width = 1, Number height = 1, Array ignoreObjects[String objectName || Number ID]=[]) Get all objects at a given location, within a given width. Adding objects to the ignoreObjects argument will exclude them from the search.
function Room.getAllAt(Number x, Number y, Boolean solidOnly = false, Number width = 1, Number height = 1) Get all objects and tiles at a given location
function Room.checkEmpty(Number x, Number y, Boolean solidOnly = false, Number width = 1, Number height = 1) Check if there is anything at a given location
number Room.width Playable room width
number Room.height Playable room height
number Room.gridX Grid X dimension
number Room.gridY Grid Y dimension
number Room.view.x X to start drawing from
number Room.view.y Y to start drawing from
number Room.view.width Width of view to draw to
number Room.view.height Height of view to draw to
number Room.id Internal unique ID
object Room.background EngineResource Background to draw behind room
object Room.view Object containing variables related to how the room is displayed on the canvas
string Room.name String used to identify the object in a room
string Room.view.objectName Object to follow with view
EngineResource Sprite(String spriteName, Number sheetX = 0, Number sheetY = 0, Number sheetWidth = 16, Number sheetHeight=16, Number drawWidth=16, Number drawHeight=16, Number animationSpeed = 1, Boolean forceNewResource=false) An image loaded from an image file used to draw tiles, objects, and backgrounds. Sprites can be from sheets, or use entire images. They can be animated, or still.
boolean Sprite.resource File resource from image
function Sprite.draw(Number x, Number y) Draws the sprite. This is usually called automatically.
function Sprite.setFrame(Number frameX=0, Number frameY=0) Jumps the sprite to a given X and Y frame in its animation.
number Sprite.speed Animation speed, if applicable
number Sprite.sheetX X to start taking sprite from. This is primarily for sprite sheets where the sprite you want to draw may not be at position 0,0. For animations, specify an array of X positions.
number Sprite.sheetY Y to start taking sprite from. This is primarily for sprite sheets where the sprite you want to draw may not be at position 0,0. For animations, specify an array of Y positions.
number Sprite.sheetWidth Width of sprite on the sheet. This is primarily for sprite sheets where the sprite you want to draw may be smaller than the entire sheet.
number Sprite.sheetHeight Height of sprite on the sheet. This is primarily for sprite sheets where the sprite you want to draw may be smaller than the entire sheet.
number Sprite.drawWidth Actual width to draw sprite in room. This will scale the sprite.
number Sprite.drawHeight Actual height to draw sprite in room. This will scale the sprite.
number Sprite.scaleX The X scale at which to draw the sprite. Supplying a negative value will cause the image to flip.
number Sprite.scaleY The Y scale at which to draw the sprite. Supplying a negative value will cause the image to flip.
number Sprite.id Internal unique ID
string Sprite.name String used to identify the sprite
string Sprite.fileName Location of file containing image or images
EngineResource Background(String color, EngineResource Sprite=-1, Boolean tiled=true) An image or color to be drawn in a room behind all objects and tiles.
string Background.color Color to draw to in room, if no sprite is present.
string Background.colour Alias of color for our friends across the pond.
number Background.sprite EngineResource Sprite to draw in room, either tiled or not.
boolean Background.tiled Whether or not to tile the sprite in the room, if it is not larger than the room.
function() Background.draw Draw the background. This is usually called automatically.
EngineResource Tile(String name, EngineResource Sprite=EngineResource Sprite(), Number x=0, Number y=0, Boolean solid=false, Array properties=[]) Decorative element to be drawn in a room. Like an object, these can be pathable, but they cannot have scripts or events attached to them.
array Tile.properties Properties to help identify this tile. Useful for water or terrain properties.
boolean Tile.solid Whether this tile should affect pathfinding
function Tile.destroy() Remove this tile from the current room.
number Tile.x X coordinate of tile in room
number Tile.y Y coordinate of tile in room
number Tile.id Internal unique ID
object Tile.sprite EngineResource Sprite to draw at the Tiles position in the room
string Tile.name String used to identify the object in a room
EngineResource Sound(String soundName, String fileName, Number volume=1,Boolean forceNewResource=false) EngineResource to play audio in game.
boolean Sound.resource JS file resource from sound
function Sound.play(Number volume) Plays the sound
function Sound.loop() Plays the sound, looping on completion
function Sound.pause() Pauses the sound, retaining its current playback position
function Sound.stop() Stops playing the sound, losing its current playback position
function Sound.seek(Number time) Seeks to a point in the sound
function Sound.setVolume(Number volume) Set the volume at which to play the sound
function Sound.mute() Mutes the sound, remembering previous volume
function Sound.unmute() Unmutes the sound, returning its playback to its previous volume
function Sound.setSpeed(Number speed) Sets the speed at which to play the sound
number Sound.id Internal unique ID
string Sound.name String used to identify the Sound
string Sound.fileName Location of file containing sound