TilerChild.cs

using UnityEngine;
using System.Collections;

// Force inject a sprite renderer before initialization (if not present)
[RequireComponent(typeof(SpriteRenderer))]

// @TODO Warning, does not take into account parallaxed weight, needs to be added manually
// @NOTE Must have a parent container
public class TilerChild : MonoBehaviour {
	public bool repeatX = false;
	public bool repeatY = false;

	// Tracking mechanism to discover the current whereabouts of a tile
	public int xAxis = 0;
	public int yAxis = 0;

	public int offsetX = 2;
	public int offsetY = 2;

	// Draw checks
	bool hasARightBuddy = false;
	bool hasALeftBuddy = false;
	bool hasATopBuddy = false;
	bool hasABottomBuddy = false;

	public bool reverseScaleX = false;
	public bool reverseScaleY = false;

	float spriteWidth;
	float spriteHeight;
	Camera cam;
	public Tiler tileApi;

	void Awake () {
		cam = Camera.main;
	}

	void Start () {
		SpriteRenderer sRenderer = GetComponent<SpriteRenderer>();
		spriteWidth = sRenderer.sprite.bounds.size.x;
		spriteHeight = sRenderer.sprite.bounds.size.y;
	}
	
	void Update () {
		if (repeatX && (hasALeftBuddy == false || hasARightBuddy == false)) {
			// Calculate half the width of what the camera can see (world coords, not pixels)
			float camHorizontalExtend = cam.orthographicSize * Screen.width / Screen.height;

			// Calculate positions where the camera can see the edge of the sprite
			float edgeVisiblePositionRight = (transform.position.x + spriteWidth / 2) - camHorizontalExtend;
			float edgeVisiblePostionLeft = (transform.position.x - spriteWidth / 2) + camHorizontalExtend;

			// Is left or right edge visible?
			if (cam.transform.position.x >= edgeVisiblePositionRight - offsetX && hasARightBuddy == false) {
				if (tileApi.IsTile(xAxis + 1, yAxis) == false) {
					MakeNewBuddyX(1);
					tileApi.AddTile(xAxis + 1, yAxis);
				} 
				hasARightBuddy = true;
			} else if (cam.transform.position.x <= edgeVisiblePostionLeft + offsetX && hasALeftBuddy == false) {
				if (tileApi.IsTile(xAxis - 1, yAxis) == false) {
					MakeNewBuddyX(-1);
					tileApi.AddTile(xAxis - 1, yAxis);
				} 
				hasALeftBuddy = true;
			}

		} else if (repeatY && (hasATopBuddy == false || hasABottomBuddy == false)) {
			float camVerticalExtend = cam.orthographicSize * Screen.height / Screen.width;

			// Calculate top and bottom visible positions
			float edgeVisiblePositionTop = (transform.position.y + spriteHeight / 2) - camVerticalExtend;
			float edgeVisiblePositionBottom = (transform.position.y - spriteHeight / 2) + camVerticalExtend;

			// Is top or bottom edge visible?
			if (cam.transform.position.y >= edgeVisiblePositionTop - offsetY && hasATopBuddy == false) {
				if (tileApi.IsTile(xAxis, yAxis + 1) == false) {
					MakeNewBuddyY(1);
					tileApi.AddTile(xAxis, yAxis + 1);
				} 
				hasATopBuddy = true;
			} else if (cam.transform.position.y <= edgeVisiblePositionBottom + offsetY && hasABottomBuddy == false) {
				if (tileApi.IsTile(xAxis, yAxis - 1) == false) {
					MakeNewBuddyY(-1);
					tileApi.AddTile(xAxis, yAxis - 1);
				}
				hasABottomBuddy = true;
			}
		}
	}

	void MakeNewBuddyX (int rightOrLeft) {
		// Calculate new pos
		Vector3 newPosition = new Vector3(transform.position.x + spriteWidth * rightOrLeft, transform.position.y, transform.position.z);
		Transform newBuddy = Instantiate(transform, newPosition, transform.rotation) as Transform;

		// Flip the tiled item in reverse (usually for non-tiled items)
		if (reverseScaleX == true) {
			newBuddy.localScale = new Vector3(newBuddy.localScale.x * -1, newBuddy.localScale.y, newBuddy.localScale.z);
		}

		if (reverseScaleY == true) {
			newBuddy.localScale = new Vector3(newBuddy.localScale.x, newBuddy.localScale.y * -1, newBuddy.localScale.z);
		}

		// Indicate pre-existing buddy is available to the element JUST created
		newBuddy.parent = transform.parent;
		if (rightOrLeft > 0) {
			newBuddy.GetComponent<TilerChild>().hasALeftBuddy = true;
		} else {
			newBuddy.GetComponent<TilerChild>().hasARightBuddy = true;
		}

		// Update the axis position properly
		newBuddy.GetComponent<TilerChild>().xAxis += rightOrLeft;
	}

	void MakeNewBuddyY (int topOrBottom) {
		// Calculate new pos
		Vector3 newPosition = new Vector3(transform.position.x, transform.position.y + spriteHeight * topOrBottom, transform.position.z);
		Transform newBuddy = Instantiate(transform, newPosition, transform.rotation) as Transform;
		
		if (reverseScaleX == true) {
			newBuddy.localScale = new Vector3(newBuddy.localScale.x * -1, newBuddy.localScale.y, newBuddy.localScale.z);
		}
		
		if (reverseScaleY == true) {
			newBuddy.localScale = new Vector3(newBuddy.localScale.x, newBuddy.localScale.y * -1, newBuddy.localScale.z);
		}
		
		newBuddy.parent = transform.parent;
		if (topOrBottom > 0) {
			newBuddy.GetComponent<TilerChild>().hasABottomBuddy = true;
		} else {
			newBuddy.GetComponent<TilerChild>().hasATopBuddy = true;
		}

		// Update the axis position properly
		newBuddy.GetComponent<TilerChild>().yAxis += topOrBottom;
	}
}