Finding Nearest Object Both Positive And Negative?

Questions & Answers
1

Hi,

I’m trying to find the closest point to where the mouse is clicked (topArrow, bottomArrow etc are Vector3 points on screen).

The problem is no matter where I click, it either says rightArrow or topArrow are closest; this is because they are both in the positive direction.

How can I fix this to return the actual closest?

Vector3 topArrow = new Vector3(0,12,0);
Vector3 bottomArrow = new Vector3(0,-12,0);
Vector3 leftArrow = new Vector3(-30,0,0);
Vector3 rightArrow = new Vector3(30,0,0);

Vector3 getNearestArrow()
	{
		Vector3 closestPos = new Vector3(0,0,0);
		float closestDistance = Mathf.Infinity;
		
		if(Vector3.Distance (topArrow,Input.mousePosition) < closestDistance)
		{
			closestDistance = Vector3.Distance (topArrow,Input.mousePosition);
			closestPos = topArrow;
		}
		
		if(Vector3.Distance (bottomArrow,Input.mousePosition) < closestDistance)
		{
			closestDistance = Vector3.Distance (bottomArrow,Input.mousePosition);
			closestPos = bottomArrow;
		}
		
		if(Vector3.Distance (leftArrow,Input.mousePosition) < closestDistance)
		{
			closestDistance = Vector3.Distance (leftArrow,Input.mousePosition);
			closestPos = leftArrow;
		}
		
		if(Vector3.Distance (rightArrow,Input.mousePosition) < closestDistance)
		{
			closestDistance = Vector3.Distance (rightArrow,Input.mousePosition);
			closestPos = rightArrow;
		}
							
		return closestPos;
	}
2

Vector3.Distance is unsigned, so you problem is not an issue with “positive direction.” You issues is that Input.mousePosition is in screen coordinates. Screen coordinates go from (0,0) in the lower left of your game to (Screen.width, Screen.height) in the upper right. In order to do the calculation you need to convert your mouse position into a world coordinates.

World coordinates are in 3D space, so to make the conversion, you have have to decide about how far in front of the camera you want the point. I’m going to assume your camera is looking down the ‘Z’ axis, and since all of your arrow Vector3 values have a ‘z’ coordinate of ‘0’, you want the point at the origin:

Vector3 v3Pos = new Vector3(Input.mousePosition.x, Input.mousePosition.y, Mathf.Abs(Camera.main.transform.position.z));
v3Pos = Camera.main.ScreenToWorldPoint(v3Pos);

After the this conversion, you can use v3Pos in place of your Input.mousePosition in all of your Vector3.Distance() calls.