EnemyPhysics.cs

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(BoxCollider))]
public class EnemyPhysics : MonoBehaviour {
	
	public LayerMask collisionMask;
	public bool hasPowerup= false;
	private BoxCollider colliderX;
	private Vector3 s;
	private Vector3 c;
	public float EnemySpeed;
	public float gravity;
	private bool offScreen = false;
	private string lastHit;
	private float skin = .005f;
	private float dirX;
	private float dirY;
	private float direction = -1;
	private Vector3 movement;
	public GameObject PowerupPrefabz;
	
	[HideInInspector]
	public bool grounded;
	[HideInInspector]
	public bool movementStopped;
	
	Ray rayV;
	Ray rayD;
	Ray rayH;
	RaycastHit hit;
	
	void Start(){
		colliderX = GetComponent<BoxCollider>();
		s = colliderX.size;
		c = colliderX.center;
		
	}
	public void move(Vector2 moveAmt) {
		
		float deltaY = moveAmt.y *Time.deltaTime;
		float deltaX = moveAmt.x;
		Vector2 p = transform.position;
		
		grounded= false;
		for (int i = 0; i <3; i++) {
			dirY = Mathf.Sign (deltaY);
			float x = (p.x + c.x - s.x/2) + s.x/2 * i;
			float y = p.y + c.y +s.y/2 * dirY;
			
			rayV = new Ray(new Vector2(x,y), new Vector2(0,dirY));
			Debug.DrawRay (rayV.origin, rayV.direction);
			if (Physics.Raycast (rayV,out hit, Mathf.Abs (deltaY) + skin, collisionMask)) {
				
				float dst = Vector3.Distance (rayV.origin, hit.point);
				
				
				if (dst > skin) {
					deltaY = -dst - skin * dirY;
				}
				else{ 
					deltaY = 0;
				}
				grounded = true;
				break;
				
			}
		}
		
		movementStopped = false;
		for (int i = 0; i <3; i++) {
			dirX = Mathf.Sign (deltaX);
			float x = p.x + c.x + s.x/2 * dirX;
			float y = (p.y + c.y - s.y/2) + s.y/2 * i;
			
			rayH = new Ray(new Vector2(x,y), new Vector2(dirX,0));
			Debug.DrawRay (rayH.origin, rayH.direction);
			if (Physics.Raycast (rayH,out hit, Mathf.Abs (deltaX) + skin, collisionMask)) {
				
				float dst = Vector3.Distance (rayH.origin, hit.point);
				
				
				if (dst > skin) {
					deltaX = dst * dirX - skin * dirX;
				}
				else{ 
					//deltaX = 0;
				}
				movementStopped = true;
				break;
				
			}
		}
		if (!grounded && !movementStopped) {
			Vector3 playerDir = new Vector3(deltaX,deltaY);
			Vector3 o = new Vector3((p.x + c.x + s.x/2 * dirX),(p.y + c.y +s.y/2 * dirY));
			Debug.DrawRay (o, playerDir.normalized);
			rayD = new Ray(o, playerDir.normalized);
			if(Physics.Raycast (rayD,Mathf.Sqrt (deltaX*deltaX + deltaY*deltaY),collisionMask)){
				grounded = true;
				deltaY = 0;
			}
		}
		
		Vector2 finalTransform = new Vector2 (deltaX,deltaY);
		if (offScreen){
			transform.Translate (new Vector2 (moveAmt.x, deltaY), Space.World);
		}
		else{
			transform.Translate(finalTransform, Space.World);	
		}
		
	}
	
	
	void OnTriggerEnter(Collider other) {
		lastHit = other.tag;
		if (lastHit =="Backboard"){
			//Debug.Log (lastHit);
		}
		else if (lastHit=="Weapon"){
			if (hasPowerup){
				Instantiate (PowerupPrefabz, transform.position, Quaternion.identity);
			}
			DestroyObject (this.gameObject);
		}
	}
	
	
	void Update () {
		
		if (lastHit == "Backboard"){
			Invoke ("SelfDestruct", 3);	
			offScreen= true;
		}
		else if (movementStopped && !offScreen) {
			direction *= -1;			
		}
		else{}
		
		float amtToMove = EnemySpeed * Time.deltaTime * direction;
		
		movement.x = amtToMove;
		movement.y -= gravity * Time.deltaTime; 
		
		
		move (movement);
		
		if (this.transform.position.y < -6){
			SelfDestruct();
		}
	}
	
	void SelfDestruct(){
		DestroyObject (this.gameObject);
	}
}