Mr Sun Studios - All about Design, Programming and Game Development.

//These variables will note which keys are down
//We don't need the up or down key just yet
//but we will later
var leftKeyDown:Boolean = false;
var upKeyDown:Boolean = false;
var rightKeyDown:Boolean = false;
var downKeyDown:Boolean = false;
//the main character's speed
var mainSpeed:Number = 7;
 
//adding a listener to mcMain which will make it move 
//based on the key strokes that are down
mcMain.addEventListener(Event.ENTER_FRAME, moveChar);
function moveChar(event:Event):void{
	//if certain keys are down then move the character
	if(leftKeyDown){
		mcMain.x -= mainSpeed;
	}
	if(rightKeyDown){
		mcMain.x += mainSpeed;
	}
	if(upKeyDown || mainJumping){
		mainJump();
	}
}
 
//listening for the keystrokes
//this listener will listen for down keystrokes
stage.addEventListener(KeyboardEvent.KEY_DOWN, checkKeysDown);
function checkKeysDown(event:KeyboardEvent):void{
	//making the booleans true based on the keycode
	//WASD Keys or arrow keys
	if(event.keyCode == 37 || event.keyCode == 65){
		leftKeyDown = true;
	}
	if(event.keyCode == 38 || event.keyCode == 87){
		upKeyDown = true;
	}
	if(event.keyCode == 39 || event.keyCode == 68){
		rightKeyDown = true;
	}
	if(event.keyCode == 40 || event.keyCode == 83){
		downKeyDown = true;
	}
}
//this listener will listen for keys being released
stage.addEventListener(KeyboardEvent.KEY_UP, checkKeysUp);
function checkKeysUp(event:KeyboardEvent):void{
	//making the booleans false based on the keycode
	if(event.keyCode == 37 || event.keyCode == 65){
		leftKeyDown = false;
	}
	if(event.keyCode == 38 || event.keyCode == 87){
		upKeyDown = false;
	}
	if(event.keyCode == 39 || event.keyCode == 68){
		rightKeyDown = false;
	}
	if(event.keyCode == 40 || event.keyCode == 83){
		downKeyDown = false;
	}
}

//whether or not the main guy is jumping
var mainJumping:Boolean = false;
//how quickly should the jump start off
var jumpSpeedLimit:int = 15;
//the current speed of the jump;
var jumpSpeed:Number = jumpSpeedLimit;

//jumping function
function mainJump():void{
	//if main isn't already jumping
	if(!mainJumping){
		//then start jumping
		mainJumping = true;
		jumpSpeed = jumpSpeedLimit*-1;
		mcMain.y += jumpSpeed;
	} else {
		//then continue jumping if already in the air
		//crazy math that I won't explain
		if(jumpSpeed < 0){
			jumpSpeed *= 1 - jumpSpeedLimit/75;
			if(jumpSpeed > -jumpSpeedLimit/5){
				jumpSpeed *= -1;
			}
		}
		if(jumpSpeed > 0 && jumpSpeed <= jumpSpeedLimit){
			jumpSpeed *= 1 + jumpSpeedLimit/50;
		}
		mcMain.y += jumpSpeed;
		//if main hits the floor, then stop jumping
		//of course, we'll change this once we create the level
		if(mcMain.y >= stage.stageHeight - mcMain.height){
			mainJumping = false;
			mcMain.y = stage.stageHeight - mcMain.height;
		}
	}
}