/// <summary>
/// The three points p0, p0 + u and p0 + v make up a triangle. If 'divisions' is 1 and 'doQuad' is false,<para/>
/// exactly this triangle will be added to the mesh. If 'divisions' is larger than 1, the triangle will be subdivided.<para/>
/// If 'doQuad' is true, the triangle is expanded to a parallelogram using the fourth point p0 + u + v.
/// </summary>
static public void AddTriangles(MeshGeometry3D mesh, int divisions, Point3D p0, Vector3D u, Vector3D v, double tu0, double tu1, bool doQuad = true)
{
TextureTransform tt = new TextureTransform(0, divisions, tu0, tu1, 1, 0);
Vector3D du = u / (double)divisions;
Vector3D dv = v / (double)divisions;
Vector3D n = u.Cross(v);
n.Normalize();
for (int iv = 0; iv < divisions; iv++)
{
int iuMax = doQuad ? divisions : divisions - iv;
for (int iu = 0; iu < iuMax; iu++)
{
Point3D p1 = p0 + iu * du + iv * dv;
Point3D p2 = p1 + du;
Point3D p3 = p1 + dv;
Point3D p4 = p2 + dv;
mesh.Positions.Add(p1);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu, iv));
mesh.Positions.Add(p2);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu + 1, iv));
mesh.Positions.Add(p3);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu, iv + 1));
int i = mesh.Positions.Count - 3;
AddTriangleIndices(mesh, i, i + 1, i + 2);
bool doUpperTriangle = doQuad ? true : iu < iuMax - 1;
if (doUpperTriangle)
{
mesh.Positions.Add(p4);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu + 1, iv + 1));
AddTriangleIndices(mesh, i + 1, i + 3, i + 2);
continue;
}
}
}
}
/// <summary>
/// The three points p0, p0 + u and p0 + v make up a triangle. If 'divisions' is 1 and 'doQuad' is false,<para/>
/// exactly this triangle will be added to the mesh. If 'divisions' is larger than 1, the triangle will be subdivided.<para/>
/// If 'doQuad' is true, the triangle is expanded to a parallelogram using the fourth point p0 + u + v.
/// </summary>
public static void AddTriangles(MeshGeometry3D mesh, int divisions, Point3D p0, Vector3D u, Vector3D v, double tu0, double tu1, bool doQuad = true)
{
TextureTransform tt = new TextureTransform(0, divisions, tu0, tu1, 1, 0);
Vector3D du = u / (double)divisions;
Vector3D dv = v / (double)divisions;
Vector3D n = u.Cross(v);
n.Normalize();
for (int iv = 0; iv < divisions; iv++)
{
int iuMax = doQuad ? divisions : divisions - iv;
for (int iu = 0; iu < iuMax; iu++)
{
Point3D p1 = p0 + iu * du + iv * dv;
Point3D p2 = p1 + du;
Point3D p3 = p1 + dv;
Point3D p4 = p2 + dv;
mesh.Positions.Add(p1);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu, iv));
mesh.Positions.Add(p2);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu + 1, iv));
mesh.Positions.Add(p3);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu, iv + 1));
int i = mesh.Positions.Count - 3;
AddTriangleIndices(mesh, i, i + 1, i + 2);
bool doUpperTriangle = doQuad ? true : iu < iuMax - 1;
if (doUpperTriangle)
{
mesh.Positions.Add(p4);
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(iu + 1, iv + 1));
AddTriangleIndices(mesh, i + 1, i + 3, i + 2);
continue;
}
}
}
}
/// <summary>
/// Mesh for a cone in the xy plane from z = 0 to z = 1.
/// </summary>
static public MeshGeometry3D CreateCone(int divisions, bool isClosed)
{
if (divisions < 3 || divisions > 999)
{
return(null);
}
TextureTransform tt = new TextureTransform(-1, 1, 0, 1, 1, 0);
MeshGeometry3D mesh = new MeshGeometry3D();
mesh.Positions.Add(new Point3D(0, 0, 1));
mesh.Normals.Add(new Vector3D(0, 0, 1));
mesh.TextureCoordinates.Add(tt.Transform(0, 0));
double dPhi = MathUtils.PIx2 / divisions;
double phi0 = dPhi * 0.5;
for (int id = 0; id <= divisions; id++)
{
double phi = phi0 + id * dPhi;
double tx = phi / MathUtils.PIx2;
double x = Math.Cos(phi);
double y = Math.Sin(phi);
mesh.Positions.Add(new Point3D(x, y, 0));
mesh.Normals.Add(new Vector3D(x, y, 0));
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (id > 0)
{
AddTriangleIndices(mesh, id, id + 1, 0);
}
}
if (isClosed)
{
AddTriangles(mesh, divisions, 1, 0, 0, 360, 0);
}
return(mesh);
}
/// <summary>
/// Add triangles for a disk segment parallel to the xy plane at a certain z value.
/// If startDegrees > stopDegrees, the triangle faces will go down the negative z axis.
/// </summary>
static void AddTriangles(MeshGeometry3D mesh, int divisions, double outerRadius, double innerRadius, double z, double startDegrees, double stopDegrees)
{
double start = MathUtils.ToRadians(startDegrees);
double stop = MathUtils.ToRadians(stopDegrees);
double dPhi = (stop - start) / divisions;
double phi0 = start;
if (IsNotMeantToBeRound(divisions, startDegrees, stopDegrees))
{
phi0 = dPhi * 0.5;
}
Vector3D n = new Vector3D(0, 0, Math.Sign(dPhi));
TextureTransform tt = new TextureTransform(-outerRadius, outerRadius, 0, 1, 1, 0);
int i0 = mesh.Positions.Count;
if (innerRadius == 0)
{
mesh.Positions.Add(new Point3D(0, 0, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(new Point(0.5, 0.5));
}
for (int id = 0; id <= divisions; id++)
{
double phi = phi0 + id * dPhi;
double cos = Math.Cos(phi);
double sin = Math.Sin(phi);
double x = outerRadius * cos;
double y = outerRadius * sin;
mesh.Positions.Add(new Point3D(x, y, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (innerRadius == 0)
{
if (id > 0)
{
int i = mesh.Positions.Count - 2;
AddTriangleIndices(mesh, i0, i, i + 1);
}
continue;
}
x = innerRadius * cos;
y = innerRadius * sin;
mesh.Positions.Add(new Point3D(x, y, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (id > 0)
{
int i = mesh.Positions.Count - 2;
AddTriangleIndices(mesh, i, i - 1, i - 2);
AddTriangleIndices(mesh, i, i + 1, i - 1);
}
}
}
/// <summary>
/// Add triangles for a disk segment parallel to the xy plane at a certain z value.
/// If startDegrees > stopDegrees, the triangle faces will go down the negative z axis.
/// </summary>
static void AddTriangles(MeshGeometry3D mesh, int divisions, double outerRadius, double innerRadius, double z, double startDegrees, double stopDegrees)
{
double start = MathUtils.ToRadians(startDegrees);
double stop = MathUtils.ToRadians(stopDegrees);
double dPhi = (stop - start) / divisions;
double phi0 = start;
if (IsNotMeantToBeRound(divisions, startDegrees, stopDegrees))
phi0 = dPhi * 0.5;
Vector3D n = new Vector3D(0, 0, Math.Sign(dPhi));
TextureTransform tt = new TextureTransform(-outerRadius, outerRadius, 0, 1, 1, 0);
int i0 = mesh.Positions.Count;
if (innerRadius == 0)
{
mesh.Positions.Add(new Point3D(0, 0, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(new Point(0.5, 0.5));
}
for (int id = 0; id <= divisions; id++)
{
double phi = phi0 + id * dPhi;
double cos = Math.Cos(phi);
double sin = Math.Sin(phi);
double x = outerRadius * cos;
double y = outerRadius * sin;
mesh.Positions.Add(new Point3D(x, y, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (innerRadius == 0)
{
if (id > 0)
{
int i = mesh.Positions.Count - 2;
AddTriangleIndices(mesh, i0, i, i + 1);
}
continue;
}
x = innerRadius * cos;
y = innerRadius * sin;
mesh.Positions.Add(new Point3D(x, y, z));
mesh.Normals.Add(n);
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (id > 0)
{
int i = mesh.Positions.Count - 2;
AddTriangleIndices(mesh, i, i - 1, i - 2);
AddTriangleIndices(mesh, i, i + 1, i - 1);
}
}
}
/// <summary>
/// Mesh for a cone in the xy plane from z = 0 to z = 1.
/// </summary>
public static MeshGeometry3D CreateCone(int divisions, bool isClosed)
{
if (divisions < 3 || divisions > 999)
return null;
TextureTransform tt = new TextureTransform(-1, 1, 0, 1, 1, 0);
MeshGeometry3D mesh = new MeshGeometry3D();
mesh.Positions.Add(new Point3D(0, 0, 1));
mesh.Normals.Add(new Vector3D(0, 0, 1));
mesh.TextureCoordinates.Add(tt.Transform(0, 0));
double dPhi = MathUtils.PIx2 / divisions;
double phi0 = dPhi * 0.5;
for (int id = 0; id <= divisions; id++)
{
double phi = phi0 + id * dPhi;
double tx = phi / MathUtils.PIx2;
double x = Math.Cos(phi);
double y = Math.Sin(phi);
mesh.Positions.Add(new Point3D(x, y, 0));
mesh.Normals.Add(new Vector3D(x, y, 0));
mesh.TextureCoordinates.Add(tt.Transform(x, y));
if (id > 0)
AddTriangleIndices(mesh, id, id + 1, 0);
}
if (isClosed)
AddTriangles(mesh, divisions, 1, 0, 0, 360, 0);
return mesh;
}
