Instant HTML5 2D Platformer - Instant HTML5 2D Platformer - page 11

6. The next step required is to initialize keyboard input and call both the KeyDown and

KeyUp events inside of the InitObjectManager constructor as follows:
document.onkeydown = function(key){objectManager.keyDown(key);}
document.onkeyup = function(key){objectManager.keyUp(key);}

7. Once a key is pressed, each of the previously declared events trigger one of two

corresponding functions, which we will now declare below the InitObjectManager
constructor.
this.keyDown = function(event) {

for (obj in this.objects) {
if (this.objects[obj].keyDown)
this.objects[obj].keyDown(event);
}
}

this.keyUp = function(event) {

for (obj in this.objects) {
if (this.objects[obj].keyUp)
this.objects[obj].keyUp(event);
}
}

8. The inal step required is to modify the object manager's Draw function. Replace the
for loop within our Draw function with the modiied loop as follows:

for (obj in this.objects) {

if (this.objects[obj].Update) {
this.objects[obj].Update(deltaTime, this.context, this.deltaX,
this.deltaY);
}

if (this.objects[obj].Draw) {
this.objects[obj].Draw(deltaTime, this.context, this.deltaX, this.
deltaY);
}
}