public void TestBaseCaseTriangle()
{
List <Point> triangleInPositiveOrientation = new List <Point>()
{
new Point(0, 0), new Point(1, 0), new Point(0, 1)
};
Int32Collection indices = SweepLinePolygonTriangulator.Triangulate(triangleInPositiveOrientation);
Assert.That(indices.Count == 3);
Assert.That(indices[0] == 0);
Assert.That(indices[1] == 1);
Assert.That(indices[2] == 2);
List <Point> triangleInNegativeOrientation = new List <Point>()
{
new Point(0, 0), new Point(0, 1), new Point(1, 0)
};
indices = SweepLinePolygonTriangulator.Triangulate(triangleInNegativeOrientation);
Assert.That(indices.Count == 3);
Assert.That(indices[0] == 0);
Assert.That(indices[1] == 2);
Assert.That(indices[2] == 1);
}
private static void CreateSimpleTriangulatedMesh(MeshBuilder meshBuilder)
{
List <Point> triangleInPositiveOrientation = new List <Point>()
{
new Point(0, 0),
new Point(1, 0),
new Point(0, 1)
};
//it's up to the user how to map 2D points to 3D, in this case we simply add a z-coordinate to the points:
IEnumerable <Point3D> triangleInXYPlane = triangleInPositiveOrientation.Select(p => new Point3D(p.X, p.Y, 0));
foreach (Point3D point in triangleInXYPlane)
{
meshBuilder.Positions.Add(point);
}
Int32Collection indices = SweepLinePolygonTriangulator.Triangulate(triangleInPositiveOrientation);
foreach (int index in indices)
{
meshBuilder.TriangleIndices.Add(index);
}
//Create a triangle with the reversed orientation, this should thus also be visible from the other side:
List <Point> triangleInNegativeOrientation = new List <Point>()
{
new Point(0, 0),
new Point(0, 1),
new Point(1, 0)
};
triangleInXYPlane = triangleInPositiveOrientation.Select(p => new Point3D(p.X, p.Y, 1));
foreach (Point3D point in triangleInXYPlane)
{
meshBuilder.Positions.Add(point);
}
indices = SweepLinePolygonTriangulator.Triangulate(triangleInNegativeOrientation);
foreach (int index in indices)
{
//add 3 as we have already added a triangle before, making the starting index of this triangle 3 higher:
meshBuilder.TriangleIndices.Add(index + 3);
}
}
/// <summary>
/// Generate a simple Polygon and then triangulate it.
/// The Result is then Displayed.
/// </summary>
/// <param name="sender">The Sender (i.e. the Button)</param>
/// <param name="e">The routet Event Args</param>
private void generatePolygonButton_Click(object sender, RoutedEventArgs e)
{
// Generate random Polygon
var random = new Random();
var cnt = mViewModel.PointCount;
mPolygonPoints = new List <Vector2>();
var angle = 0f;
var angleDiff = 2f * (Single)Math.PI / cnt;
var radius = 4f;
// Random Radii for the Polygon
var radii = new List <float>();
var innerRadii = new List <float>();
for (int i = 0; i < cnt; i++)
{
radii.Add(random.NextFloat(radius * 0.9f, radius * 1.1f));
innerRadii.Add(random.NextFloat(radius * 0.2f, radius * 0.3f));
}
var hole1 = new List <Vector2>();
var hole2 = new List <Vector2>();
var holeDistance = 2f;
var holeAngle = random.NextFloat(0, (float)Math.PI * 2);
var cos = (float)Math.Cos(holeAngle);
var sin = (float)Math.Sin(holeAngle);
var offset1 = new Vector2(holeDistance * cos, holeDistance * sin);
var offset2 = new Vector2(-holeDistance * cos, -holeDistance * sin);
for (int i = 0; i < cnt; i++)
{
// Flatten a bit
var radiusUse = radii[i];
mPolygonPoints.Add(new Vector2(radii[i] * (Single)Math.Cos(angle), radii[i] * (Single)Math.Sin(angle)));
hole1.Add(offset1 + new Vector2(innerRadii[i] * (Single)Math.Cos(-angle), innerRadii[i] * (Single)Math.Sin(-angle)));
hole2.Add(offset2 + new Vector2(innerRadii[i] * (Single)Math.Cos(-angle), innerRadii[i] * (Single)Math.Sin(-angle)));
angle += angleDiff;
}
var holes = new List <List <Vector2> >()
{
hole1, hole2
};
// Triangulate and measure the Time needed for the Triangulation
var before = DateTime.Now;
var sLTI = SweepLinePolygonTriangulator.Triangulate(mPolygonPoints, holes);
var after = DateTime.Now;
// Generate the Output
var geometry = new HelixToolkit.Wpf.SharpDX.MeshGeometry3D();
geometry.Positions = new HelixToolkit.Wpf.SharpDX.Core.Vector3Collection();
geometry.Normals = new HelixToolkit.Wpf.SharpDX.Core.Vector3Collection();
foreach (var point in mPolygonPoints.Union(holes.SelectMany(h => h)))
{
geometry.Positions.Add(new Vector3(point.X, 0, point.Y + 5));
geometry.Normals.Add(new Vector3(0, 1, 0));
}
geometry.Indices = new HelixToolkit.Wpf.SharpDX.Core.IntCollection(sLTI);
triangulatedPolygon.Geometry = geometry;
var lb = new LineBuilder();
for (int i = 0; i < sLTI.Count; i += 3)
{
lb.AddLine(geometry.Positions[sLTI[i]], geometry.Positions[sLTI[i + 1]]);
lb.AddLine(geometry.Positions[sLTI[i + 1]], geometry.Positions[sLTI[i + 2]]);
lb.AddLine(geometry.Positions[sLTI[i + 2]], geometry.Positions[sLTI[i]]);
}
mViewModel.LineGeometry = lb.ToLineGeometry3D();
// Set the Lines if activated
if (mViewModel.ShowTriangleLines)
{
lineTriangulatedPolygon.Geometry = mViewModel.LineGeometry;
}
else
{
lineTriangulatedPolygon.Geometry = null;
}
// Set the InfoLabel Text
var timeNeeded = (after - before).TotalMilliseconds;
infoLabel.Content = String.Format("Last triangulation of {0} Points took {1:0.##} Milliseconds!", triangulatedPolygon.Geometry.Positions.Count, timeNeeded);
}
/// <summary>
/// Triangulate the polygon by using the sweep line algorithm
/// </summary>
/// <returns>An index collection.</returns>
public Int32Collection Triangulate()
{
return(SweepLinePolygonTriangulator.Triangulate(this.points));
}
/// <summary>
/// Generate a simple Polygon and then triangulate it.
/// The Result is then Displayed.
/// </summary>
/// <param name="sender">The Sender (i.e. the Button)</param>
/// <param name="e">The routet Event Args</param>
private void generatePolygonButton_Click(object sender, RoutedEventArgs e)
{
// Generate random Polygon
var random = new Random();
var cnt = mViewModel.PointCount;
mPolygonPoints = new List <Vector2>();
var angle = 0f;
var angleDiff = 2f * (Single)Math.PI / cnt;
var radius = 4f;
// Random Radii for the Polygon
var radii = new List <float>();
for (int i = 0; i < cnt; i++)
{
radii.Add(radius + random.NextFloat(-radius, radius));
}
for (int i = 0; i < cnt; i++)
{
var last = i > 0 ? i - 1 : cnt - 1;
var next = i < cnt - 1 ? i + 1 : 0;
// Flatten a bit
var radiusUse = radii[last] * 0.25f + radii[i] * 0.5f + radii[next] * 0.25f;
mPolygonPoints.Add(new Vector2(radiusUse * (Single)Math.Cos(angle), radiusUse * (Single)Math.Sin(angle)));
angle += angleDiff;
}
// Triangulate and measure the Time needed for the Triangulation
var before = DateTime.Now;
var sLTI = SweepLinePolygonTriangulator.Triangulate(mPolygonPoints);
var after = DateTime.Now;
// Generate the Output
var geometry = new HelixToolkit.Wpf.SharpDX.MeshGeometry3D();
geometry.Positions = new HelixToolkit.Wpf.SharpDX.Core.Vector3Collection();
geometry.Normals = new HelixToolkit.Wpf.SharpDX.Core.Vector3Collection();
foreach (var point in mPolygonPoints)
{
geometry.Positions.Add(new Vector3(point.X, 0, point.Y + 5));
geometry.Normals.Add(new Vector3(0, 1, 0));
}
geometry.Indices = new HelixToolkit.Wpf.SharpDX.Core.IntCollection(sLTI);
triangulatedPolygon.Geometry = geometry;
var lb = new LineBuilder();
for (int i = 0; i < sLTI.Count; i += 3)
{
lb.AddLine(geometry.Positions[sLTI[i]], geometry.Positions[sLTI[i + 1]]);
lb.AddLine(geometry.Positions[sLTI[i + 1]], geometry.Positions[sLTI[i + 2]]);
lb.AddLine(geometry.Positions[sLTI[i + 2]], geometry.Positions[sLTI[i]]);
}
mViewModel.LineGeometry = lb.ToLineGeometry3D();
// Set the Lines if activated
if (mViewModel.ShowTriangleLines)
{
lineTriangulatedPolygon.Geometry = mViewModel.LineGeometry;
}
else
{
lineTriangulatedPolygon.Geometry = null;
}
// Set the InfoLabel Text
var timeNeeded = (after - before).TotalMilliseconds;
infoLabel.Content = String.Format("Last triangulation of {0} Points took {1:0.##} Milliseconds!", triangulatedPolygon.Geometry.Positions.Count, timeNeeded);
}