Move player according to the camera direction

Question

Hi, I want to be able to make my player move forward in different directions depending on what direction the camera is facing, so say if by default my player moved north when I pressed W (W = forward), how could I make it that if my camera was facing east my player would follow in the east direction instead of the north? I will list my Camera and Movement script files below...

Camera file:

 [Header("Variables")]
 public Transform player;

 [Space]
 [Header("Position")]
 public float camPosX;
 public float camPosY;
 public float camPosZ;

 [Space]
 [Header("Rotation")]
 public float camRotationX;
 public float camRotationY;
 public float camRotationZ;

 [Space]
 [Range(0f, 10f)]
 public float turnSpeed;

 //Misc
 public static bool CamOrbit = true;

 private void Start()
 {
     offset = new Vector3(player.position.x + camPosX, player.position.y + camPosY, player.position.z + camPosZ);
     transform.rotation = Quaternion.Euler(camRotationX, camRotationY, camRotationZ);
 }


 private void LateUpdate()
 {
     offset = Quaternion.AngleAxis(Input.GetAxis("Mouse X") * turnSpeed, Vector3.up) * Quaternion.AngleAxis(Input.GetAxis("Mouse Y") * turnSpeed, Vector3.right) * offset;
     transform.position = player.position + offset;
     transform.LookAt(player.position);
 }

Movement file:

 //"rb" Is A Reference To Rigidbody
 public Rigidbody rb;

 //Internal Names To Change Values In Unity
 public float forwardForce = 100f;
 public float sidewayForce = 100f;
 public float backwardForce = 100f;

 //Controls For Player
 void FixedUpdate ()
 {
     if (Input.GetKey("w"))
     {
         rb.AddForce(0, 0, forwardForce * Time.deltaTime, ForceMode.VelocityChange);
     }

     if (Input.GetKey("a"))
     {
         rb.AddForce(-sidewayForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
     }

     if (Input.GetKey("s"))
     {
         rb.AddForce(0, 0, -backwardForce * Time.deltaTime, ForceMode.VelocityChange);
     }

     if (Input.GetKey("d"))
     {
         rb.AddForce(sidewayForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
     }
 }

Answer 1

Best Answer

Answer by Vyzier · Mar 23, 2018 at 02:06 PM

Try this: for each of your AddForce, make it so that you're passing a whole Vector3 parameter instead of separate floats. Then pass them the main camera's transform.forward/right multiplied by the amount of forces and Time.deltaTime. So, something like this:

 // I'm just making variables for these things so our lines of code don't get too long
 Vector3 forward = Camera.main.transform.forward;
 Vector3 right = Camera.main.transform.right;
 
 // The .normalized here is important
 Vector3 forwardDir = new Vector3(forward.x, 0, forward.z).normalized;
 Vector3 rightDir = new Vector3(right.x, 0, right.z).normalized;
 
 if (Input.GetKey(KeyCode.W))
 {
     rb.AddForce(forwardDir * forwardForce * Time.deltaTime,
                 ForceMode.VelocityChange);
 }
 
 if (Input.GetKey(KeyCode.A))
 {
      rb.AddForce(rightDir * -sidewayForce * Time.deltaTime, 
                  ForceMode.VelocityChange);
 }
 
 if (Input.GetKey(KeyCode.S))
 {
     rb.AddForce(forwardDir * -backwardForce * Time.deltaTime,
                 ForceMode.VelocityChange);
 }
 
 if (Input.GetKey(KeyCode.D))
 {
     rb.AddForce(rightDir * sidewayForce * Time.deltaTime, 
                 ForceMode.VelocityChange);
 }

Edit: Updated answer so the direction of movement doesn't include the y-axis.

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gm091203 · Mar 23, 2018 at 03:29 PM 0

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That works so good! Thank you so much... The only problem is, is when moving forward it's really slow, I've tried to change the force but it still seems to be going a bit slow, any idea why?

Vyzier gm091203 · Mar 23, 2018 at 04:51 PM 0

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Hmm.. I guess you can try changing the Force$$anonymous$$ode. Have you tried changing the force values to some ridiculous number? I'm not on my PC at the moment, so I can't really check this out right now.

gm091203 Vyzier · Mar 23, 2018 at 05:01 PM 0

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Yeah, I changed the force values the only dilemma with that is it mess' with my gravity and physics and launches you when you leave the edge of a game object...

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Move player according to the camera direction

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