Limiting distance while moving an object with mouse

Questions & Answers
1

I`m trying to come with an Angry Birds clone in top down perspective, 3D.
So, I have a sling and a bird.

  1. To move the bird with a mouse I use ScreenPointToRay. Cast a ray from the camera and see if it hit a plane where my sling is placed.
  2. To limit the drag distance between the bird and a sling I use a ray again. This time its cast from the sling in the direction of the bird. In case my draggin exceeds maximum stretch distance (lets say it is 4), I place my bird on this ray, at point 4.

Here is my code:

using UnityEngine;
using System.Collections;

public class super : MonoBehaviour {

	int floorMask;                      // A layer mask so that a ray can be cast just at gameobjects on the floor layer.
	float camRayLength = 100f;          // The length of the ray from the camera into the scene.
	public Transform ass;
	public Ray rayToMouse;
	private Vector3 playerToMouse;


	// Use this for initialization

	void Start () {
		floorMask = LayerMask.GetMask ("Floor");
		rayToMouse = new Ray (ass.position, Vector3.zero);
		}
	
	// Update is called once per frame
	void Update () {
		float Distance = Vector3.Distance (ass.position, transform.position);
				
	
		// Create a ray from the mouse cursor on screen in the direction of the camera.
		Ray camRay = Camera.main.ScreenPointToRay (Input.mousePosition);
		
		// Create a RaycastHit variable to store information about what was hit by the ray.
		RaycastHit floorHit;
		
		// Perform the raycast and if it hits something on the floor layer...


			if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask) && Distance <= 4)
		{
				Vector3 playerToMouse = floorHit.point;
				playerToMouse.y = 0f;
			transform.position = playerToMouse;		
		}

		else if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask) && Distance >= 4)
		{
			Vector3 playerToMouse = floorHit.point;
			playerToMouse = floorHit.point;
			rayToMouse.direction = playerToMouse;
			playerToMouse = rayToMouse.GetPoint (4);
			playerToMouse.y = 0f;
			transform.position = playerToMouse;				
		}
	}
}

Instead of doing what I intended, when I drag the bird to the maximum stretch it begins to blink. One frame it`s away from max distance, another — within in.
How should I fix it?
Thanks.

2

the firts thing that hit my eye is that your 2 conditions

if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask) && Distance <= 4)

and

else if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask) && Distance >= 4)

both satisfy the condition when distance is == 4. Therefore you should add a block of instructions

else {...}

that finally tells what to do when distance == 4 and modify the others removing the equal sign