public TwoFingerGesture(NSSet touches, ARSCNView view, VirtualObject parentObject, VirtualObjectManager manager) : base(touches, view, parentObject, manager)
{
var tArray = touches.ToArray <UITouch>();
FirstTouch = tArray[0];
SecondTouch = tArray[1];
var firstTouchPoint = FirstTouch.LocationInView(SceneView);
var secondTouchPoint = SecondTouch.LocationInView(SceneView);
InitialMidpoint = firstTouchPoint.Add(secondTouchPoint).Divide(2f);
// Compute the two other corners of the rectangle defined by the two fingers
// and compute the points in between.
var thirdCorner = new CGPoint(firstTouchPoint.X, secondTouchPoint.Y);
var fourthCorner = new CGPoint(secondTouchPoint.X, firstTouchPoint.Y);
// Compute points in between.
var midpoints = new[]
{
thirdCorner.Add(firstTouchPoint).Divide(2f),
thirdCorner.Add(secondTouchPoint).Divide(2f),
fourthCorner.Add(firstTouchPoint).Divide(2f),
fourthCorner.Add(secondTouchPoint).Divide(2f),
InitialMidpoint.Add(firstTouchPoint).Divide(2f),
InitialMidpoint.Add(secondTouchPoint).Divide(2f),
InitialMidpoint.Add(thirdCorner).Divide(2f),
InitialMidpoint.Add(fourthCorner).Divide(2f)
};
// Check if any of the two fingers or their midpoint is touching the object.
// Based on that, translation, rotation and scale will be enabled or disabled.
var allPoints = new List <CGPoint>(new[] { firstTouchPoint, secondTouchPoint, thirdCorner, fourthCorner, InitialMidpoint });
allPoints.AddRange(midpoints);
FirstTouchedObject = allPoints.Select(pt => this.VirtualObjectAt(pt)).Where(vo => vo != null).FirstOrDefault();
if (FirstTouchedObject != null)
{
ObjectBaseScale = FirstTouchedObject.Scale.X;
AllowTranslation = true;
AllowRotation = true;
InitialDistanceBetweenFingers = (firstTouchPoint.Subtract(secondTouchPoint)).Length();
InitialFingerAngle = Math.Atan2(InitialMidpoint.X, InitialMidpoint.Y);
InitialObjectAngle = FirstTouchedObject.EulerAngles.Y;
}
else
{
AllowTranslation = false;
AllowRotation = false;
}
}
override protected void UpdateGesture(object state)
{
// Two finger touch enables combined translation, rotation and scale.
if (FirstTouchedObject == null)
{
return;
}
var virtualObject = FirstTouchedObject;
// First: Update the touches.
if (currentTouches.Count < 2)
{
return;
}
var tAry = currentTouches.ToArray <UITouch>();
var newTouch1 = tAry[0];
var newTouch2 = tAry[1];
if (newTouch1.GetHashCode() == FirstTouch.GetHashCode())
{
FirstTouch = newTouch1;
SecondTouch = newTouch2;
}
else
{
FirstTouch = newTouch2;
SecondTouch = newTouch1;
}
InvokeOnMainThread(() =>
{
var loc1 = FirstTouch.LocationInView(SceneView);
var loc2 = SecondTouch.LocationInView(SceneView);
if (AllowTranslation)
{
// 1. Translation using the midpoint between the two fingers.
UpdateTranslation(virtualObject, loc1.MidPoint(loc2));
}
var spanBetweenTouches = loc1.Subtract(loc2);
if (AllowRotation)
{
// 2. Rotation based on the relative rotation of the fingers on a unit circle.
UpdateRotation(virtualObject, spanBetweenTouches);
}
});
}
public static void CallFirstTouch()
{
FirstTouch?.Invoke();
}
