koobas.hobune.stream
Math: How to rotate a wheel by drag&drop (Canvas, 2D)?
I'm struggling with probably simple math to spin/rotate a wheel using drag&drop.
There is a Radial Layout in a Canvas (Unity UI) and it can already be rotated by setting a property called StartAngle that is in a range from 0-360. In this Radial there are items, so the StartAngle is for the first item and places all the child elements around the layout radius.
I want to implement drag & drop for the items so that you can drag a child around and the Radial will spin accordingly (infinitely).
Right now, I have this as a starting point:
public void OnDrag(PointerEventData eventData)
{
var delta = eventData.delta.x * Time.deltaTime;
var newAngle = radialLayout.StartAngle + delta;
if (newAngle >= 360)
newAngle = newAngle - 360;
else if (newAngle < 0)
newAngle = Mathf.Abs(360 - newAngle);
radialLayout.StartAngle = newAngle;
}
It kind of works but doesn't feel very smooth. This is for mobile/touch, so I want both the X and Y delta of the drag operation to be taken into account. Apparently, the y delta is not considered in my example and I have no idea how to incorporate this correctly. The user might do a linear drag & drop on either axis or he/she might also do like a circular drag movement.
So how can I map mouse movement to a rotation angle from 0-360 so that it feels good?
