2D over 3D anti-aliasing artifacts - wpf

Question

We have 3D models in WPF and use a cursor made from a Canvas and some internal parts. We turn the HW cursor off and move the Canvas through MouseEvent. The issue is that there are terrible artifacts on the screen as you move from left to right (not nearly as bad right to left). I have played with snaptodevicepixels, Edge mode and nvidea AA settings but the only thing that "fixes" is setting edge mode to aliased for the 3dviewport - and we don't want that. I have even made the cursor completely transparent and it still leaves artifacts.
I broke out some of the code for demonstration. You can especially see the artifacts moving upper-left to lower-right.
Anyone think they can help me out here? I'm head banging and not in a good way. It's looking more like a bug in the AA code.
Thanks
T
FYI: I used some Petzold code here for the beach ball.
Bad AA BeachBall
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Windows.Shapes;
namespace Cursoraa2
{
class Program : Window
{
[STAThread]
public static void Main() => new Application().Run(new Program());
public Program()
{
Width = 500;
Height = 500;
var grid = new Grid();
var viewport = new Viewport3D();
grid.Children.Add(viewport);
Content = grid;
//RenderOptions.SetEdgeMode(viewport,EdgeMode.Aliased);
DynamicCurosr.Start(grid, grid, 40, Color.FromArgb(40, 0x33, 0x33, 0xff), Colors.Blue);
MouseMove += MainWindow_MouseMove;
MakeBeachBallSphere(viewport);
}
private void MainWindow_MouseMove(object sender, MouseEventArgs e) => DynamicCurosr.Move(e.GetPosition(this));
public void MakeBeachBallSphere(Viewport3D viewport)
{
// Get the MeshGeometry3D from the GenerateSphere method.
var mesh = GenerateSphere(new Point3D(0, 0, 0), 1, 36, 18);
mesh.Freeze();
// Define a brush for the sphere.
var brushes = new Brush[6] { Brushes.Red, Brushes.Blue,
Brushes.Yellow, Brushes.Orange,
Brushes.White, Brushes.Green };
var drawgrp = new DrawingGroup();
for (var i = 0; i < brushes.Length; i++)
{
var rectgeo = new RectangleGeometry(new Rect(10 * i, 0, 10, 60));
var geodraw = new GeometryDrawing(brushes[i], null, rectgeo);
drawgrp.Children.Add(geodraw);
}
var drawbrsh = new DrawingBrush(drawgrp);
drawbrsh.Freeze();
// Define the GeometryModel3D.
var geomod = new GeometryModel3D
{
Geometry = mesh,
Material = new DiffuseMaterial(drawbrsh)
};
// Create a ModelVisual3D for the GeometryModel3D.
var modvis = new ModelVisual3D { Content = geomod };
viewport.Children.Add(modvis);
// Create another ModelVisual3D for light.
var modgrp = new Model3DGroup();
modgrp.Children.Add(new AmbientLight(Color.FromRgb(128, 128, 128)));
modgrp.Children.Add(new DirectionalLight(Color.FromRgb(128, 128, 128), new Vector3D(2, -3, -1)));
modvis = new ModelVisual3D {Content = modgrp};
viewport.Children.Add(modvis);
// Create the camera.
var cam = new PerspectiveCamera(new Point3D(0, 0, 8), new Vector3D(0, 0, -1), new Vector3D(0, 1, 0), 45);
viewport.Camera = cam;
// Create a transform for the GeometryModel3D.
var axisangle = new AxisAngleRotation3D(new Vector3D(1, 1, 0), 180);
var rotate = new RotateTransform3D(axisangle);
geomod.Transform = rotate;
// Animate the RotateTransform3D.
//DoubleAnimation anima = new DoubleAnimation(360, new Duration(TimeSpan.FromSeconds(5)));
//anima.RepeatBehavior = RepeatBehavior.Forever;
//axisangle.BeginAnimation(AxisAngleRotation3D.AngleProperty, anima);
}
MeshGeometry3D GenerateSphere(Point3D center, double radius, int slices, int stacks)
{
// Create the MeshGeometry3D.
var mesh = new MeshGeometry3D();
// Fill the Position, Normals, and TextureCoordinates collections.
for (var stack = 0; stack <= stacks; stack++)
{
var phi = Math.PI / 2 - stack * Math.PI / stacks;
var y = radius * Math.Sin(phi);
var scale = -radius * Math.Cos(phi);
for (var slice = 0; slice <= slices; slice++)
{
var theta = slice * 2 * Math.PI / slices;
var x = scale * Math.Sin(theta);
var z = scale * Math.Cos(theta);
var normal = new Vector3D(x, y, z);
mesh.Normals.Add(normal);
mesh.Positions.Add(normal + center);
mesh.TextureCoordinates.Add(
new Point((double)slice / slices,
(double)stack / stacks));
}
}
// Fill the TriangleIndices collection.
for (var stack = 0; stack < stacks; stack++)
for (var slice = 0; slice < slices; slice++)
{
var n = slices + 1; // Keep the line length down.
if (stack != 0)
{
mesh.TriangleIndices.Add((stack + 0) * n + slice);
mesh.TriangleIndices.Add((stack + 1) * n + slice);
mesh.TriangleIndices.Add((stack + 0) * n + slice + 1);
}
if (stack != stacks - 1)
{
mesh.TriangleIndices.Add((stack + 0) * n + slice + 1);
mesh.TriangleIndices.Add((stack + 1) * n + slice);
mesh.TriangleIndices.Add((stack + 1) * n + slice + 1);
}
}
return mesh;
}
}
public static class DynamicCurosr
{
static public bool InSession { get; private set; }
private static Panel theCursor;
private static readonly ScaleTransform ScaleTransform = new ScaleTransform(1, 1);
private static readonly MatrixTransform MatrixTransform = new MatrixTransform(1, 0, 0, 1, 0, 0);
private static Color defaultFill = Color.FromArgb(20, 255, 255, 255);
private static Color fillFromUser;
private static double strokeFromUser = 0;
private static Color strokeColorFromUser = Colors.Black;
private static int centerDotSizeFromUser = 10; // need to get from user
private static double initialDiameter = double.NaN;
private static Panel cursorPanel;
private static Panel mousePanel;
public static bool Start(Panel cursorPanelIn, Panel mousePanelIn, double radius)
{
return Start(cursorPanelIn, mousePanelIn, radius, defaultFill);
}
public static bool Start(Panel cursorPanelIn, Panel mousePanelIn, double radius, Color fill, Color strokeColor = default(Color), double strokeSize = .16)
{
strokeColor = strokeColor == default(Color) ? Colors.Black : strokeColor;
strokeColorFromUser = strokeColor;
fillFromUser = fill;
strokeFromUser = strokeColor == default(Color) ? 0 : strokeSize;
initialDiameter = double.IsNaN(initialDiameter) ? radius * 2 : initialDiameter;
return Start(cursorPanelIn, mousePanelIn);
}
private static bool Start(Panel cursorPanelIn, Panel mousePanelIn)
{
if (InSession) return false;
cursorPanel = cursorPanelIn;
mousePanel = mousePanelIn;
var point = Mouse.GetPosition(cursorPanel);
theCursor = MakeACursor(theCursor, initialDiameter / 2);
InSession = true;
cursorPanel.Cursor = Cursors.None;
theCursor.Visibility = Visibility.Visible;
Move(point);
if (cursorPanel.Children.Contains(theCursor))
return false;
cursorPanel.Children.Add(theCursor);
Mouse.OverrideCursor = Cursors.None;
return true;
}
public static void Stop()
{
if (InSession)
{
Mouse.OverrideCursor = null;
theCursor.Visibility = Visibility.Collapsed;
cursorPanel.Children.Remove(theCursor);
InSession = false;
}
}
public static void Move(Point point)
{
if (InSession && theCursor.Visibility == Visibility.Visible)
{
var m = MatrixTransform.Matrix;
m.OffsetX = point.X - theCursor.Width / 2;
m.OffsetY = point.Y - theCursor.Height / 2;
MatrixTransform.Matrix = m;
theCursor.RenderTransform = MatrixTransform;
}
}
public static Panel MakeACursor(Panel theCursor, double radius, Color fillColorIn = default(Color), Color strokeColorIn = default(Color))
{
var strokeColor = new SolidColorBrush(strokeColorIn == default(Color) ? strokeColorFromUser : strokeColorIn);
if (theCursor == null)
{
theCursor = new Grid()
{
Width = radius * 2,
Height = radius * 2,
Background = null,
VerticalAlignment = VerticalAlignment.Top,
HorizontalAlignment = HorizontalAlignment.Left,
RenderTransform = ScaleTransform,
RenderTransformOrigin = new Point(.5, .5),
};
var cursorElement = new Ellipse
{
Width = radius * 2,
Height = radius * 2,
Fill = new SolidColorBrush(fillColorIn == default(Color) ? fillFromUser : fillColorIn),
HorizontalAlignment = HorizontalAlignment.Left,
VerticalAlignment = VerticalAlignment.Top,
StrokeThickness = strokeFromUser,
Stroke = strokeColor,
RenderTransformOrigin = new Point(.5, .5)
};
theCursor.Children.Add(cursorElement);
}
MakeCursorOverlay(theCursor, radius, strokeColor);
return theCursor;
}
public static void MakeCursorOverlay(Panel theCursor, double radius, SolidColorBrush strokeColor)
{
var save = theCursor.Children[0];
theCursor.Children.Clear();
theCursor.Children.Add(save);
var circle = new Ellipse
{
Width = centerDotSizeFromUser,
Height = centerDotSizeFromUser,
Fill = null,
HorizontalAlignment = HorizontalAlignment.Center,
VerticalAlignment = VerticalAlignment.Center,
StrokeThickness = strokeFromUser,
Stroke = strokeColor,
RenderTransformOrigin = new Point(.5, .5)
};
theCursor.Children.Add(circle);
}
}
}