ScrollingBitmap.hx

package com.stencyl.models.scene;

import openfl.display.Sprite;
import openfl.display.Bitmap;
import com.stencyl.Engine;

class ScrollingBitmap extends Sprite
{
	public var image1:Bitmap; //Center
	public var image2:Bitmap; //W
	public var image3:Bitmap; //E
	public var image4:Bitmap; //NW
	public var image5:Bitmap; //N
	public var image6:Bitmap; //NE
	public var image7:Bitmap; //SW
	public var image8:Bitmap; //S
	public var image9:Bitmap; //SE
	
	public var speed:Float;
	public var curStep:Float;
	
	public var running:Bool;
	public var parallax:Bool;
	public var scrolling:Bool;
	
	public var cacheWidth:Float;
	public var cacheHeight:Float;
	
	public var xP:Float;
	public var yP:Float;
	public var xPos:Float;
	public var yPos:Float;
	public var xVelocity:Float;
	public var yVelocity:Float;
	public var parallaxX:Float;
	public var parallaxY:Float;
	
	public var backgroundID:Int;
	public var repeats:Bool;
	
	public function new(img:Dynamic, dx:Float, dy:Float, px:Float=0, py:Float=0, ID:Int=0, repeats:Bool = true) 
	{
		super();
		
		curStep = 0;
	
		running = true;
		this.repeats = repeats;
		
		image1 = new Bitmap(img);
		addChild(image1);
		
		cacheWidth = image1.width;
		cacheHeight = image1.height;
        
		if (repeats)
		{
			image2 = new Bitmap(img);
			image2.x = image1.x-cacheWidth;
			addChild(image2);
			
			image3 = new Bitmap(img);
			image3.x = image1.x+cacheWidth;
			addChild(image3);
			
			//
			
			image4 = new Bitmap(img);
			image4.x = image1.x-cacheWidth;
			image4.y = image1.y-cacheHeight;
			addChild(image4);
			
			image5 = new Bitmap(img);
			image5.y = image1.y-cacheHeight;
			addChild(image5);
			
			image6 = new Bitmap(img);
			image6.x = image1.x+cacheWidth;
			image6.y = image1.y-cacheHeight;
			addChild(image6);
			
			//
			
			image7 = new Bitmap(img);
			image7.x = image1.x-cacheWidth;
			image7.y = image1.y+cacheHeight;
			addChild(image7);
			
			image8 = new Bitmap(img);
			image8.y = image1.y+cacheHeight;
			addChild(image8);
			
			image9 = new Bitmap(img);
			image9.x = image1.x+cacheWidth;
			image9.y = image1.y+cacheHeight;
			addChild(image9);
		}
		
		xP = 0;
		yP = 0;
		
		xPos = 0;
        yPos = 0;
        
        xVelocity = dx;
        yVelocity = dy;
		
		parallaxX = px;
		parallaxY = py;
		
		scrolling = (dx  != 0 || dy != 0);
		parallax = (px != 0 || py != 0);
		
		backgroundID = ID;
	}
	
	public function update(x:Float, y:Float, elapsedTime:Float)
	{
		var needsReset:Bool = false;
		
		if(parallax)
		{
			xPos = -Std.int(x * parallaxX);
			yPos = -Std.int(y * parallaxY);

			needsReset = true;
		}
		else if(running)
		{
			xPos = 0;
			yPos = 0;
		}
		else
		{
			xPos = xP;
			yPos = yP;
		}

		if(scrolling && running)
		{
			var width = cacheWidth;
			var height = cacheHeight;
			
			xP += xVelocity / 10.0 * Engine.SCALE;
			yP += yVelocity / 10.0 * Engine.SCALE;
			
			if (this.repeats)
			{
				if(xP < -width || xP > width)
				{
					xP = xP % width;
				}
				
				if(yP < -height || yP > height)
				{
					yP = yP % height;
				}
			}
	        
	        xPos += Math.floor(xP);
	        yPos += Math.floor(yP);
	        
			curStep += 1;
			
			if(curStep >= 1) 
			{
				needsReset = true;
					        
				curStep -= Math.floor(curStep);
			}
		}
		
		if(needsReset)
		{
			//TODO: optimize?
			resetPositions();
		}
	}
	
	public function resetPositions()
	{
		cacheWidth = image1.width;
		cacheHeight = image1.height;
		
		if (this.repeats)
		{
			if (xPos < -cacheWidth)
			{
				xPos = xPos % cacheWidth;
			}
			
			if (yPos < -cacheHeight)
			{
				yPos = yPos % cacheHeight;
			}
		}

		image1.x = xPos;
	    image1.y = yPos;
	        
		if (this.repeats)
		{
			image2.x = xPos - cacheWidth;
			image2.y = yPos;
				
			image3.x = xPos + cacheWidth;
			image3.y = yPos;
				
			image4.x = xPos - cacheWidth;
			image4.y = yPos - cacheHeight;
				
			image5.x = xPos;
			image5.y = yPos - cacheHeight;
				
			image6.x = xPos + cacheWidth;
			image6.y = yPos - cacheHeight;
				
			image7.x = xPos - cacheWidth;
			image7.y = yPos + cacheHeight;
				
			image8.x = xPos;
			image8.y = yPos + cacheHeight;
				
			image9.x = xPos + cacheWidth;
			image9.y = yPos + cacheHeight;
		}
	}
	
	public function start()
	{
		running = true;
	}
	
	public function stop()
	{
		running = false;
	}
}