using UnityEngine;
using System;

public class AnimateSprite : MonoBehaviour
{
 
	//vars for the whole sheet
	public int colCount =  4;
	public int rowCount =  4;
	 
	//vars for animation
	public int  rowNumber  =  0; //Zero Indexed
	public int colNumber = 0; //Zero Indexed
	public int totalCells = 4;
	public int  fps     = 10;
	
	private Vector2 offset;
	
	//Update
	void Update () { SetSpriteAnimation(colCount,rowCount,rowNumber,colNumber,totalCells,fps);  }
 
	//SetSpriteAnimation
	void SetSpriteAnimation(int colCount ,int rowCount ,int rowNumber ,int colNumber,int totalCells,int fps ){
	 
	    // Calculate index
	    int index  = (int)(Time.time * fps);
	    // Repeat when exhausting all cells
	    index = index % totalCells;
	 
	    // Size of every cell
	    float sizeX = 1.0f / colCount;
	    float sizeY = 1.0f / rowCount;
	    Vector2 size =  new Vector2(sizeX,sizeY);
	 
	    // split into horizontal and vertical index
	    var uIndex = index % colCount;
	    var vIndex = index / colCount;
	 
	    // build offset
	    // v coordinate is the bottom of the image in opengl so we need to invert.
	    float offsetX = (uIndex+colNumber) * size.x;
	    float offsetY = (1.0f - size.y) - (vIndex + rowNumber) * size.y;
	    Vector2 offset = new Vector2(offsetX,offsetY);
	 
	    GetComponent<Renderer>().material.SetTextureOffset ("_MainTex", offset);
	    GetComponent<Renderer>().material.SetTextureScale  ("_MainTex", size);
	}
}