private SCNNode FocusSquareNode()
{
if (focusSquareNode == null)
{
/*
* The focus square consists of eight Segments as follows, which can be individually animated.
*
* s1 s2
* _ _
* s3 | | s4
*
* s5 | | s6
* - -
* s7 s8
*/
var sl = 0.5f; // segment length
var c = FocusSquareThickness / 2f; // correction to align lines perfectly
var s1 = new FocusSquareSegment("s1", Corner.TopLeft, Alignment.Horizontal);
var s2 = new FocusSquareSegment("s2", Corner.TopRight, Alignment.Horizontal);
var s3 = new FocusSquareSegment("s3", Corner.TopLeft, Alignment.Vertical);
var s4 = new FocusSquareSegment("s4", Corner.TopRight, Alignment.Vertical);
var s5 = new FocusSquareSegment("s5", Corner.BottomLeft, Alignment.Vertical);
var s6 = new FocusSquareSegment("s6", Corner.BottomRight, Alignment.Vertical);
var s7 = new FocusSquareSegment("s7", Corner.BottomLeft, Alignment.Horizontal);
var s8 = new FocusSquareSegment("s8", Corner.BottomRight, Alignment.Horizontal);
s1.Position = s1.Position.Add(new SCNVector3(-(sl / 2 - c), -(sl - c), 0));
s2.Position = s2.Position.Add(new SCNVector3(sl / 2 - c, -(sl - c), 0));
s3.Position = s3.Position.Add(new SCNVector3(-sl, -sl / 2, 0));
s4.Position = s4.Position.Add(new SCNVector3(sl, -sl / 2, 0));
s5.Position = s5.Position.Add(new SCNVector3(-sl, sl / 2, 0));
s6.Position = s6.Position.Add(new SCNVector3(sl, sl / 2, 0));
s7.Position = s7.Position.Add(new SCNVector3(-(sl / 2 - c), sl - c, 0));
s8.Position = s8.Position.Add(new SCNVector3(sl / 2 - c, sl - c, 0));
var planeNode = new SCNNode();
planeNode.EulerAngles = new SCNVector3((float)(Math.PI / 2), planeNode.EulerAngles.Y, planeNode.EulerAngles.Z);
planeNode.SetUniformScale(FocusSquareSize * ScaleForClosedSquare);
planeNode.AddChildNode(s1);
planeNode.AddChildNode(s2);
planeNode.AddChildNode(s3);
planeNode.AddChildNode(s4);
planeNode.AddChildNode(s5);
planeNode.AddChildNode(s6);
planeNode.AddChildNode(s7);
planeNode.AddChildNode(s8);
planeNode.AddChildNode(FillPlane);
segments = new FocusSquareSegment[] { s1, s2, s3, s4, s5, s6, s7, s8 };
IsOpen = false;
// Always render focus square on top
planeNode.RenderOnTop();
focusSquareNode = planeNode;
}
return(focusSquareNode);
}