using UnityEngine;
using System.Collections;


public class Utils {
	public static Rect GetCameraRect2D(Camera cam){
		float pixWidth = (cam.orthographicSize * Camera.main.aspect) * 2;
		float pixHeight = cam.orthographicSize * 2;
		
		return new Rect(
			Camera.main.transform.localPosition.x - (pixWidth * 0.5f), 
			Camera.main.transform.localPosition.y + (pixHeight * 0.5f),
			pixWidth, pixHeight);
	}
	
	public static Rect RectFromBounds(Bounds b){
		return new Rect (b.center.x - b.size.x * 0.5f, b.center.y + b.size.y * 0.5f, b.size.x, b.size.y);
	}
	
}



public class ParallaxBackground : MonoBehaviour {
	public float scrollSpeed = 0.5f;
	public bool KeepTextureAspect = true;
	public Camera cam;
	public float Scale = 0.01f;
	public float LerpSpeed = 0.5f;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {

		Vector2 offset = gameObject.renderer.sharedMaterial.mainTextureOffset;
		Vector3 mousePos = Input.mousePosition;
		Vector2 screenCenter = new Vector2 (Screen.width / 2, Screen.height / 2);
		Vector2 mouseDir = new Vector2 (mousePos.x, mousePos.y) - screenCenter;
		Vector2 nextOffset = mouseDir * -Scale;

		gameObject.renderer.sharedMaterial.mainTextureOffset = Vector2.Lerp (offset, nextOffset, LerpSpeed * Time.deltaTime);
		//offset.x += tcScrollSpeed * Time.deltaTime;
		//gameObject.renderer.sharedMaterial.mainTextureOffset =offset;


		/*float textureAspect = gameObject.renderer.sharedMaterial.mainTexture.width / gameObject.renderer.sharedMaterial.mainTexture.height;
		float textureScale = cam.aspect / textureAspect;
		var camRect = Utils.GetCameraRect2D (cam);
		float tcScrollSpeed = textureScale * scrollSpeed;

		if (Application.isPlaying) {
			Vector2 offset = gameObject.renderer.sharedMaterial.mainTextureOffset;
			offset.x += tcScrollSpeed * Time.deltaTime;
			gameObject.renderer.sharedMaterial.mainTextureOffset =offset;
		}


		if (KeepTextureAspect) {

			gameObject.renderer.sharedMaterial.mainTextureScale = new Vector2(textureScale, 1);
		}

		transform.localScale = new Vector3 (camRect.width, camRect.height, 1);*/
	}
}