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vtkRecursiveSphereDirectionEncoder

Section: Visualization Toolkit Volume Rendering Classes

# Usage

vtkRecursiveSphereDirectionEncoder is a direction encoder which uses the vertices of a recursive subdivision of an octahedron (with the vertices pushed out onto the surface of an enclosing sphere) to encode directions into a two byte value.

To create an instance of class vtkRecursiveSphereDirectionEncoder, simply invoke its constructor as follows

      obj = vtkRecursiveSphereDirectionEncoder

# Methods

The class vtkRecursiveSphereDirectionEncoder has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, `obj` is an instance of the vtkRecursiveSphereDirectionEncoder class.

- `string = obj.GetClassName ()`
- `int = obj.IsA (string name)`
- `vtkRecursiveSphereDirectionEncoder = obj.NewInstance ()`
- `vtkRecursiveSphereDirectionEncoder = obj.SafeDownCast (vtkObject o)`
- `int = obj.GetEncodedDirection (float n[3])` - Given a normal vector n, return the encoded direction
- `float = obj.GetDecodedGradient (int value)` - / Given an encoded value, return a pointer to the normal vector
- `int = obj.GetNumberOfEncodedDirections (void )` - Return the number of encoded directions
- `obj.SetRecursionDepth (int )` - Set / Get the recursion depth for the subdivision. This indicates how many time one triangle on the initial 8-sided sphere model is replaced by four triangles formed by connecting triangle edge midpoints. A recursion level of 0 yields 8 triangles with 6 unique vertices. The normals are the vectors from the sphere center through the vertices. The number of directions will be 11 since the four normals with 0 z values will be duplicated in the table - once with +0 values and the other time with -0 values, and an addition index will be used to represent the (0,0,0) normal. If we instead choose a recursion level of 6 (the maximum that can fit within 2 bytes) the number of directions is 16643, with 16386 unique directions and a zero normal.
- `int = obj.GetRecursionDepthMinValue ()` - Set / Get the recursion depth for the subdivision. This indicates how many time one triangle on the initial 8-sided sphere model is replaced by four triangles formed by connecting triangle edge midpoints. A recursion level of 0 yields 8 triangles with 6 unique vertices. The normals are the vectors from the sphere center through the vertices. The number of directions will be 11 since the four normals with 0 z values will be duplicated in the table - once with +0 values and the other time with -0 values, and an addition index will be used to represent the (0,0,0) normal. If we instead choose a recursion level of 6 (the maximum that can fit within 2 bytes) the number of directions is 16643, with 16386 unique directions and a zero normal.
- `int = obj.GetRecursionDepthMaxValue ()` - Set / Get the recursion depth for the subdivision. This indicates how many time one triangle on the initial 8-sided sphere model is replaced by four triangles formed by connecting triangle edge midpoints. A recursion level of 0 yields 8 triangles with 6 unique vertices. The normals are the vectors from the sphere center through the vertices. The number of directions will be 11 since the four normals with 0 z values will be duplicated in the table - once with +0 values and the other time with -0 values, and an addition index will be used to represent the (0,0,0) normal. If we instead choose a recursion level of 6 (the maximum that can fit within 2 bytes) the number of directions is 16643, with 16386 unique directions and a zero normal.
- `int = obj.GetRecursionDepth ()` - Set / Get the recursion depth for the subdivision. This indicates how many time one triangle on the initial 8-sided sphere model is replaced by four triangles formed by connecting triangle edge midpoints. A recursion level of 0 yields 8 triangles with 6 unique vertices. The normals are the vectors from the sphere center through the vertices. The number of directions will be 11 since the four normals with 0 z values will be duplicated in the table - once with +0 values and the other time with -0 values, and an addition index will be used to represent the (0,0,0) normal. If we instead choose a recursion level of 6 (the maximum that can fit within 2 bytes) the number of directions is 16643, with 16386 unique directions and a zero normal.