public static Mesh Compute(Ellipsoid ellipsoid, int numberOfSlicePartitions, int numberOfStackPartitions, GeographicGridEllipsoidVertexAttributes vertexAttributes)
{
if (numberOfSlicePartitions < 3)
{
throw new ArgumentOutOfRangeException("numberOfSlicePartitions");
}
if (numberOfStackPartitions < 2)
{
throw new ArgumentOutOfRangeException("numberOfStackPartitions");
}
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.Position) != GeographicGridEllipsoidVertexAttributes.Position)
{
throw new ArgumentException("Positions must be provided.", "vertexAttributes");
}
Mesh mesh = new Mesh();
mesh.PrimitiveType = PrimitiveType.Triangles;
mesh.FrontFaceWindingOrder = WindingOrder.Counterclockwise;
int numberOfVertices = NumberOfVertices(numberOfSlicePartitions, numberOfStackPartitions);
VertexAttributeDoubleVector3 positionsAttribute = new VertexAttributeDoubleVector3("position", numberOfVertices);
mesh.Attributes.Add(positionsAttribute);
IndicesUnsignedInt indices = new IndicesUnsignedInt(3 * NumberOfTriangles(numberOfSlicePartitions, numberOfStackPartitions));
mesh.Indices = indices;
IList <Vector3H> normals = null;
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.Normal) == GeographicGridEllipsoidVertexAttributes.Normal)
{
VertexAttributeHalfFloatVector3 normalsAttribute = new VertexAttributeHalfFloatVector3("normal", numberOfVertices);
mesh.Attributes.Add(normalsAttribute);
normals = normalsAttribute.Values;
}
IList <Vector2H> textureCoordinates = null;
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.TextureCoordinate) == GeographicGridEllipsoidVertexAttributes.TextureCoordinate)
{
VertexAttributeHalfFloatVector2 textureCoordinateAttribute = new VertexAttributeHalfFloatVector2("textureCoordinate", numberOfVertices);
mesh.Attributes.Add(textureCoordinateAttribute);
textureCoordinates = textureCoordinateAttribute.Values;
}
//
// Create lookup table
//
double[] cosTheta = new double[numberOfSlicePartitions];
double[] sinTheta = new double[numberOfSlicePartitions];
for (int j = 0; j < numberOfSlicePartitions; ++j)
{
double theta = Trig.TwoPi * (((double)j) / numberOfSlicePartitions);
cosTheta[j] = Math.Cos(theta);
sinTheta[j] = Math.Sin(theta);
}
//
// Create positions
//
IList <Vector3D> positions = positionsAttribute.Values;
positions.Add(new Vector3D(0, 0, ellipsoid.Radii.Z));
for (int i = 1; i < numberOfStackPartitions; ++i)
{
double phi = Math.PI * (((double)i) / numberOfStackPartitions);
double sinPhi = Math.Sin(phi);
double xSinPhi = ellipsoid.Radii.X * sinPhi;
double ySinPhi = ellipsoid.Radii.Y * sinPhi;
double zCosPhi = ellipsoid.Radii.Z * Math.Cos(phi);
for (int j = 0; j < numberOfSlicePartitions; ++j)
{
positions.Add(new Vector3D(cosTheta[j] * xSinPhi, sinTheta[j] * ySinPhi, zCosPhi));
}
}
positions.Add(new Vector3D(0, 0, -ellipsoid.Radii.Z));
if ((normals != null) || (textureCoordinates != null))
{
for (int i = 0; i < positions.Count; ++i)
{
Vector3D deticSurfaceNormal = ellipsoid.GeodeticSurfaceNormal(positions[i]);
if (normals != null)
{
normals.Add(deticSurfaceNormal.ToVector3H());
}
if (textureCoordinates != null)
{
textureCoordinates.Add(SubdivisionUtility.ComputeTextureCoordinate(deticSurfaceNormal));
}
}
}
//
// Triangle fan top row
//
for (int j = 1; j < numberOfSlicePartitions; ++j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(0, j, j + 1));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(0, numberOfSlicePartitions, 1));
//
// Middle rows are triangle strips
//
for (int i = 0; i < numberOfStackPartitions - 2; ++i)
{
int topRowOffset = (i * numberOfSlicePartitions) + 1;
int bottomRowOffset = ((i + 1) * numberOfSlicePartitions) + 1;
for (int j = 0; j < numberOfSlicePartitions - 1; ++j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + j, bottomRowOffset + j + 1, topRowOffset + j + 1));
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + j, topRowOffset + j + 1, topRowOffset + j));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + numberOfSlicePartitions - 1, bottomRowOffset, topRowOffset));
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + numberOfSlicePartitions - 1, topRowOffset, topRowOffset + numberOfSlicePartitions - 1));
}
//
// Triangle fan bottom row
//
int lastPosition = positions.Count - 1;
for (int j = lastPosition - 1; j > lastPosition - numberOfSlicePartitions; --j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(lastPosition, j, j - 1));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(lastPosition, lastPosition - numberOfSlicePartitions, lastPosition - 1));
return(mesh);
}
public static Mesh Compute(Ellipsoid ellipsoid, int numberOfSlicePartitions, int numberOfStackPartitions, GeographicGridEllipsoidVertexAttributes vertexAttributes)
{
if (numberOfSlicePartitions < 3)
{
throw new ArgumentOutOfRangeException("numberOfSlicePartitions");
}
if (numberOfStackPartitions < 2)
{
throw new ArgumentOutOfRangeException("numberOfStackPartitions");
}
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.Position) != GeographicGridEllipsoidVertexAttributes.Position)
{
throw new ArgumentException("Positions must be provided.", "vertexAttributes");
}
Mesh mesh = new Mesh();
mesh.PrimitiveType = PrimitiveType.Triangles;
mesh.FrontFaceWindingOrder = WindingOrder.Counterclockwise;
int numberOfVertices = NumberOfVertices(numberOfSlicePartitions, numberOfStackPartitions);
VertexAttributeDoubleVector3 positionsAttribute = new VertexAttributeDoubleVector3("position", numberOfVertices);
mesh.Attributes.Add(positionsAttribute);
IndicesUnsignedInt indices = new IndicesUnsignedInt(3 * NumberOfTriangles(numberOfSlicePartitions, numberOfStackPartitions));
mesh.Indices = indices;
IList<Vector3H> normals = null;
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.Normal) == GeographicGridEllipsoidVertexAttributes.Normal)
{
VertexAttributeHalfFloatVector3 normalsAttribute = new VertexAttributeHalfFloatVector3("normal", numberOfVertices);
mesh.Attributes.Add(normalsAttribute);
normals = normalsAttribute.Values;
}
IList<Vector2H> textureCoordinates = null;
if ((vertexAttributes & GeographicGridEllipsoidVertexAttributes.TextureCoordinate) == GeographicGridEllipsoidVertexAttributes.TextureCoordinate)
{
VertexAttributeHalfFloatVector2 textureCoordinateAttribute = new VertexAttributeHalfFloatVector2("textureCoordinate", numberOfVertices);
mesh.Attributes.Add(textureCoordinateAttribute);
textureCoordinates = textureCoordinateAttribute.Values;
}
//
// Create lookup table
//
double[] cosTheta = new double[numberOfSlicePartitions];
double[] sinTheta = new double[numberOfSlicePartitions];
for (int j = 0; j < numberOfSlicePartitions; ++j)
{
double theta = Trig.TwoPi * (((double)j) / numberOfSlicePartitions);
cosTheta[j] = Math.Cos(theta);
sinTheta[j] = Math.Sin(theta);
}
//
// Create positions
//
IList<Vector3D> positions = positionsAttribute.Values;
positions.Add(new Vector3D(0, 0, ellipsoid.Radii.Z));
for (int i = 1; i < numberOfStackPartitions; ++i)
{
double phi = Math.PI * (((double)i) / numberOfStackPartitions);
double sinPhi = Math.Sin(phi);
double xSinPhi = ellipsoid.Radii.X * sinPhi;
double ySinPhi = ellipsoid.Radii.Y * sinPhi;
double zCosPhi = ellipsoid.Radii.Z * Math.Cos(phi);
for (int j = 0; j < numberOfSlicePartitions; ++j)
{
positions.Add(new Vector3D(cosTheta[j] * xSinPhi, sinTheta[j] * ySinPhi, zCosPhi));
}
}
positions.Add(new Vector3D(0, 0, -ellipsoid.Radii.Z));
if ((normals != null) || (textureCoordinates != null))
{
for (int i = 0; i < positions.Count; ++i)
{
Vector3D deticSurfaceNormal = ellipsoid.GeodeticSurfaceNormal(positions[i]);
if (normals != null)
{
normals.Add(deticSurfaceNormal.ToVector3H());
}
if (textureCoordinates != null)
{
textureCoordinates.Add(SubdivisionUtility.ComputeTextureCoordinate(deticSurfaceNormal));
}
}
}
//
// Triangle fan top row
//
for (int j = 1; j < numberOfSlicePartitions; ++j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(0, j, j + 1));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(0, numberOfSlicePartitions, 1));
//
// Middle rows are triangle strips
//
for (int i = 0; i < numberOfStackPartitions - 2; ++i)
{
int topRowOffset = (i * numberOfSlicePartitions) + 1;
int bottomRowOffset = ((i + 1) * numberOfSlicePartitions) + 1;
for (int j = 0; j < numberOfSlicePartitions - 1; ++j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + j, bottomRowOffset + j + 1, topRowOffset + j + 1));
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + j, topRowOffset + j + 1, topRowOffset + j));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + numberOfSlicePartitions - 1, bottomRowOffset, topRowOffset));
indices.AddTriangle(new TriangleIndicesUnsignedInt(bottomRowOffset + numberOfSlicePartitions - 1, topRowOffset, topRowOffset + numberOfSlicePartitions - 1));
}
//
// Triangle fan bottom row
//
int lastPosition = positions.Count - 1;
for (int j = lastPosition - 1; j > lastPosition - numberOfSlicePartitions; --j)
{
indices.AddTriangle(new TriangleIndicesUnsignedInt(lastPosition, j, j - 1));
}
indices.AddTriangle(new TriangleIndicesUnsignedInt(lastPosition, lastPosition - numberOfSlicePartitions, lastPosition - 1));
return mesh;
}
