void OnMouseDown()
{
beingDragged = true; // Start dragging.
touchOffset = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position; //offset between the cursor and the block centre
lastSnap = transform.position; // this is obviously where we snapped the last time
bounds = SlidingPuzzleExample.CalculateSlidingBounds(transform.position, transform.lossyScale); // create default bounds
SlidingPuzzleExample.RegisterObstacle(transform, true); // marks this space as free in the matrix (or else we won't be able to return back here)
}
///<summary>This is where the dragging logic takes places.</summary>
void Drag()
{
// the destination is where the cursor points (minus the offset) clamped by the bounds
Vector3 destination = ClampPosition(Camera.main.ScreenToWorldPoint(Input.mousePosition) - touchOffset);
destination.z = transform.position.z;
// now use that information to get the new bounds
bounds = SlidingPuzzleExample.CalculateSlidingBounds(lastSnap, transform.lossyScale);
// simulate a snap to the grid so we can get potentially new bounds in the next step
lastSnap = ClampPosition(SlidingPuzzleExample.mainGrid.AlignVector3(destination, transform.lossyScale));
// move to the destination!
transform.position = destination;
}