IBM Visualization Data Explorer Programmer's Reference

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DXAddFaceNormal, DXAddFaceNormals

Function Adds connection-dependent normals to a Field.

Syntax


#include <dx/dx.h>
Field DXAddFaceNormal(Field f, int id, Vector v)
Field DXAddFaceNormals(Field f, int start, int n, Vector *v)

.

Functional Details A Field may contain connection-dependent normals that can be used to flat-shade a polygonal object. If so, the normals component is expected to have the same size as the "connections" component, as indicated by its having a "dep" attribute of "connections." Both routines aid in constructing such a component.

DXAddFaceNormal

Adds one normal (v) to f with the specified zero-based id. If f does not contain a "normals" component, one is added.

DXAddFaceNormals

Adds n normals (*v) to f. Identifiers begin with start. If f does not contain a "normals" component, one is added.

Note:Both routines are suitable for adding a small number of face normals and for rapid prototyping, but they are included here mainly for backward compatibility. For better performance, see DXAddArrayData and "Irregular Arrays".

Normals are specified as Vectors and defined as follows:


typedef struct point {
    float x, y, z;
} Point, Vector;

Note:These routines do not check the "dep" attribute of the "normals" component. Thus, if a "normals" component that is "dep" on "positions" already exists in f, the routine adds one or more normals to the normals component, leaving the attribute unchanged. The result may be a component with the wrong number of items for "dep."

Return Value Returns f or returns NULL and sets an error code.

See Also DXAddArrayData, DXAddPoint, ...Color, ...FrontColor, ...BackColor, ...Opacity, ...Normal,

"Points and Dependent Data".


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