NAME

DoTriangleStrip − Create a triangle strip primitive object

SYNOPSIS

C:

DtObject DoTriangleStrip(colormodel, vertextype,
vertexcount, vertices)
DtColorModel colormodel;
DtVertexType vertextype;
DtInt vertexcount;
DtReal vertices[];

FORTRAN:

INTEGER∗4 DOTRIS(COLMOD, VTXTYP, VTXCNT,
VTXS)
INTEGER∗4 COLMOD
INTEGER∗4 VTXTYP
INTEGER∗4 VTXCNT
REAL∗8 VTXS(∗)

DESCRIPTION

DoTriangleStrip creates a primitive object that defines a strip of connected triangles. 

The parameter colormodel specifies the color model used if the vertices contain color information for shading purposes. 

The parameter vertextype specifies the exact nature of the vertices.  FORTRANr more information, refer to Chapter 6, Doré Vertex Types, in the Doré Reference Manual or to the VertexTypes on-line manual page.) 

The parameter vertexcount contains the number of vertices in the strip.  The first three vertices make up the first triangle.  Each additional vertex adds an additional triangle, using the new vertex along with the preceding two vertices.  This means that the number of triangles drawn is two less than the number of vertices. 

The parameter vertices is an array of vertex data. 

The geometric normal to each triangle is calculated using the right-hand rule (when the fingers of the right hand point in the order of the vertices, the thumb points in the direction of the normal) for triangles 1, 3, 5, etc.  The left-hand rule is used for triangles 2, 4, 6, etc.  These normals are sometimes used for backface culling and facet shading. 

ERRORS

DoTriangleStrip must be called with at least three vertices. 

[WARNING - invalid parameter]

SEE ALSO

DoTriangleMesh(3D), DoTriangleList(3D), DoVarTriangleStrip(3D), VertexTypes(3D)

September 02, 1992