How to move game object towards mouse on x and z only?

Questions & Answers
1

I’ve been trying to figure this out for weeks but what I want to do is launch a projectile towards the mouse location. The game is iso style but Im having trouble converting the mouse location to 3d space, I want the ray to be locked at the same height as the sphere when I do that though the ray no longer follows the mouse and I don’t know how to fix that. Also there is an invisible plane stretching out that detects the mouse, to detect the depth in the world. Thanks for taking the time to help or read this.
Code below

void Update () 
	{
		//when energy is in hand, holding left mouse enables to aim ball
		if(Input.GetMouseButton(0) && velocity == Vector3.zero)
		{

			ray = Camera.main.ScreenPointToRay (new Vector3(Input.mousePosition.x, Input.mousePosition.y, 
				energy.transform.position.z - Camera.main.transform.position.z));

		////////ray.direction = new Vector3 (ray.direction.x, Mathf.Clamp(ray.direction.y, energy.transform.position.y, energy.transform.position.y), ray.direction.z);//Clamped, but doesn't follow mouse

		}
}//end of update

void FixedUpdate()
	{
		energy.transform.position += velocity * travelSpeed * Time.deltaTime;

		RaycastHit hit;
		if(Physics.Raycast(ray, out hit, 10000, mouseHitPoint))
		{

			Debug.Log (hit.point.x);
			Debug.DrawRay (energy.transform.position, new Vector3(ray.direction.x, transform.position.y, ray.direction.z) * 200, Color.black);
		}

		if(releasedEnergy == true)
		{
			travelSpeed = 15f;
			velocity = new Vector3(ray.direction.x, 0, ray.direction.z) * travelSpeed * Time.deltaTime;
			energy.transform.parent = null;
		}

		if(destroyEnergy == true)
		{
			travelSpeed = 3;
			velocity = new Vector3 (0, travelSpeed, 0);
		}
	}//end of FixedUpdate
2

if(Input.GetMouseButton(0) && velocity == Vector3.zero)
{
ray = Camera.main.ScreenPointToRay (new Vector3(Input.mousePosition.x, Input.mousePosition.y,
energy.transform.position.z - Camera.main.transform.position.z));
}

Don’t supply any z value here. Always supply 0. You want the ray to begin from the 0th ‘depth’ pixel, from the pixel which is on the surface of your monitor.

Paremeters supplied into ScreenPointToRay have nothing to do with the world-coordinates.

They are in pixels, relative to your screen’s lower left corner. The resulting ray however, will have its components in the world-space, so you can use them as usual world coordinates.

I believe the code should be:

 void FixedUpdate()
     {
          //when energy is in hand, holding left mouse enables to aim ball
         if(Input.GetMouseButton(0) && velocity == Vector3.zero)
         {
             ray = Camera.main.ScreenPointToRay (new Vector3(Input.mousePosition.x, Input.mousePosition.y, 0));

         energy.transform.position += velocity * travelSpeed * Time.deltaTime;
         Vector3 dir = Vector3.zero;

         RaycastHit hit;
         if(Physics.Raycast(ray, out hit, 10000, mouseHitPoint))
         {
              dir =  new Vector3(hit.point.x, yourWantedHeightAboiveGround, hit.point.z) - energy.transform.position;
             Debug.Log (hit.point.x);
             Debug.DrawLine (transform.position, transform.position + dir), Color.black);
         }
 
         if(releasedEnergy == true)
         {
             travelSpeed = 15f;
            
             velocity = dir.normalized * travelSpeed * Time.deltaTime;
             energy.transform.parent = null;
         }
 
         if(destroyEnergy == true)
         {
             travelSpeed = 3;
             velocity = new Vector3 (0, travelSpeed, 0);
         }
     }//end of FixedUpdate