Doors: add 2D visualization by using TryToGraphicsBuffers override

LayoutFunctions/Doors/dependencies/Door.cs

@@ -29,6 +29,102 @@ public static bool CanFit(Line wallLine, DoorType type, double width)
             return wallLine.Length() - doorWidth > DOOR_FRAME_WIDTH * 2;
         }
 
+        public override bool TryToGraphicsBuffers(out List<GraphicsBuffers> graphicsBuffers, out string id, out glTFLoader.Schema.MeshPrimitive.ModeEnum? mode)
+        {
+            List<Vector3> points = new List<Vector3>();
+            points.AddRange(DoorSchema(true, false, 90));
+            if( Type == DoorType.Double)
+            {
+                points.AddRange(DoorSchema(false, false, 90));
+            }
+
+            GraphicsBuffers buffer = new GraphicsBuffers();
+            Color color = Colors.Black;
+            for (int i = 0; i < points.Count; i++)
+            {
+                buffer.AddVertex(points[i], default, default, color);
+                buffer.AddIndex((ushort)i);
+            }
+
+            id = $"{this.Id}_door";
+            // Only one type is allowed, since line are not linked into one loop, LINES is used.
+            // This mean that each line segment need both endpoints stored, often duplicated.
+            mode = glTFLoader.Schema.MeshPrimitive.ModeEnum.LINES;
+            graphicsBuffers = new List<GraphicsBuffers> { buffer };
+            return true;
+        }
+
+        private List<Vector3> DoorSchema(bool leftSide, bool inside, double angle)
+        {
+            var doorWidth = Type == DoorType.Double ? ClearWidth / 2 : ClearWidth;
+
+            // Depending on which side door in there are different offsets.
+            var doorOffset = leftSide ? ClearWidth / 2 : -ClearWidth / 2;
+            var horizontalOffset = leftSide ? DOOR_THICKNESS : -DOOR_THICKNESS;
+            var verticalOffset = inside ? DOOR_THICKNESS : -DOOR_THICKNESS;
+            var widthOffset = inside ? doorWidth : -doorWidth;
+
+            // Draw open door silhouette rectangle.
+            Vector3 corner = Vector3.XAxis * doorOffset;
+            var c0 = corner + Vector3.YAxis * verticalOffset;
+            var c1 = c0 + Vector3.YAxis * widthOffset;
+            var c2 = c1 - Vector3.XAxis * horizontalOffset;
+            var c3 = c0 - Vector3.XAxis * horizontalOffset;
+
+            // Rotate silhouette is it's need to be drawn as partially open.
+            if (!angle.ApproximatelyEquals(90))
+            {
+                Transform t = new Transform();
+                double rotation = 90 - angle;
+                if (!leftSide)
+                {
+                    rotation = -rotation;
+                }
+
+                if (!inside)
+                {
+                    rotation = -rotation;
+                }
+
+                t.RotateAboutPoint(c0, Vector3.ZAxis, rotation);
+                c1 = t.OfPoint(c1);
+                c2 = t.OfPoint(c2);
+                c3 = t.OfPoint(c3);
+            }
+            List<Vector3> points = new List<Vector3>() { c0, c1, c1, c2, c2, c3, c3, c0 };
+
+            // Calculated correct arc angles based on door orientation.
+            double adjustedAngle = inside ? angle : -angle;
+            double anchorAngle = leftSide ? 180 : 0;
+            double endAngle = leftSide ? 180 - adjustedAngle : adjustedAngle;
+            if (endAngle < 0)
+            {
+                endAngle = 360 + endAngle;
+                anchorAngle = 360;
+            }
+
+            // If arc is constructed from bigger angle to smaller is will have incorrect domain 
+            // with max being smaller than min and negative length.
+            // ToPolyline will return 0 points for it.
+            // Until it's fixed angles should be aligned manually.
+            bool flipEnds = endAngle < anchorAngle;
+            if (flipEnds)
+            {
+                (anchorAngle, endAngle) = (endAngle, anchorAngle);
+            }
+
+            // Draw the arc from closed door to opened door.
+            Arc arc = new Arc(c0, doorWidth, anchorAngle, endAngle);
+            var tessalatedArc = arc.ToPolyline((int)(Math.Abs(angle) / 2));
+            for (int i = 0; i < tessalatedArc.Vertices.Count - 1; i++)
+            {
+                points.Add(tessalatedArc.Vertices[i]);
+                points.Add(tessalatedArc.Vertices[i + 1]);
+            }
+
+            return points;
+        }
+
         public override void UpdateRepresentations()
         {
             Vector3 left = Vector3.XAxis * ClearWidth / 2;