Intermediate Unity Sushi

Move the Player

  • Create a folder in your Assets folder and name it Scripts. Now create a new C# script in your new folder. When you create a script, you want to know what it does, so give it a descriptive name, for example PlayerController.

  • Attach your new script to your Player object.

  • Open the script and add this code inside the Update function:

Vector3 mousePos = Input.mousePosition;
mousePos.z = 15f;
transform.position = Camera.main.ScreenToWorldPoint(mousePos);

What does the code do?

A Vector3s is a structure. A structure stores multiple variables in one unit.

Unity uses Vector3 to keep track of an object’s position in the world — its (X, Y, Z) coordinates. So, when you set the Vector3 equal to the Input.mouseposition, the x and y values of the Vector3 are changed each frame (because it is in the Update function).

Input.mousePosition doesn’t change the z value of the Vector3. With the second line of code, you’re setting the z value by using . (called the ‘dot operator’).

The third line of code moves the Player object to the position of the mouse:

  • transform.position changes the location of your Player object
  • Camera.main.ScreenToWorldPoint(mousePos) sets the position of your Player object in the game world
  • Now try to run your game!

What is something that you might want to change about where the Player object goes?

Getting a better view

It can be helpful to arrange your Unity window so that you can see both the Scene tab and the Game tab at the same time when you test your game.

In the Scene tab, you can change the angle you’re viewing from, and zoom out so that you can see objects that go “off the screen”. This can be quite usefu, for example when an object is not appearing and you want to work out why, or where it went.

The Scene and Game view with the Scene zoomed out

  • Did you notice that the Player object doesn’t stay on the screen? You can fix this by adding this section of code below the code you’ve already added.
Vector3 spritePos = Camera.main.WorldToViewportPoint(transform.position);
spritePos.x = Mathf.Clamp(spritePos.x, 0.05f, 0.95f);
spritePos.y = Mathf.Clamp(spritePos.y, 0.1f, 0.9f);
transform.position = Camera.main.ViewportToWorldPoint(spritePos);

What does the code do?

The first line of code here gets the position of our Player object.

You can then use the Mathf function Clamp to keep the Player object within the camera’s viewpoint. Clamp restricts the position of the Player object by preventing the values of its X and Y coordinates from exceeding the given values.

Now the Player object follows your cursor, but it would be nice to remove the cursor now!

  • Adding this line of code into the Start function does will get rid of the cursor:
Cursor.visible = false;
  • Try running the game and moving the Player object with your mouse!
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