Detecting which way my mouse is moving the most

Hello,

Assuming you only want the directions up, down, left and right, I'll give a few suggestions:

Check which axis has the highest magnitude:

 //first we find whether the x or the y axis have a higher magnitude
 
 float xmag = Mathf.Abs(mouseDelta.x);
 float ymag = Mathf.Abs(mouseDelta.y);
 
 if (xmag > ymag) {
     //mouse is moving mostly along the x axis
     
     if (mouseDelta.x > 0) {
         //RIGHT
     }
     else {
         //LEFT
     }
 }
 else if (ymag < xmag) {
     //mouse is moving mostly along y axis
     
     if (mouseDelta.y > 0) {
         //UP
     }
     else {
         //DOWN
     }
 }
 else {
     //NO MOVEMENT
     //OR PERFECTLY SIDEWAYS
 }

Use the dot product to find which axis the direction of mouseDelta is closest to:

 //will get a 0/0 error if mouse does not move
 Vector3 direction = mouseDelta.normalized;
 
 float dot = Vector3.Dot(direction, Vector3.up);
 if (dot > 0.5) { //can be >= for sideways
     //UP
 }
 else if (dot < -0.5) { //can be <= for sideways
     //DOWN
 }
 else {
     dot = Vector3.Dot(direction, Vector3.right);
     if (dot > 0.5) { //can be >= for sideways
         //RIGHT
     }
     else if (dot < -0.5) { //can be <= for sideways
         //LEFT
     }
 }

As you can see, both methods are quite compact, while one handles sideways movement more easily and the other handles no movement more easily. The latter method can also be expanded to support more directions while the upper method is restricted to the number of dimensions.

Hope this helps,
Benproductions1