glEdgeFlag

NAME

glEdgeFlag -- flag edges as either boundary or nonboundary

C SPECIFICATION

void glEdgeFlag(GLboolean flag)

PARAMETERS

flag
Specifies the current edge flag value, either true or false.

C SPECIFICATION

void glEdgeFlagv(const GLboolean *flag)

PARAMETERS

flag
Specifies a pointer to an array that contains a single Boolean element, which replaces the current edge flag.

DESCRIPTION

Each vertex of a polygon, separate triangle, or separate quadriliteral specified between a glBegin/ glEnd pair is marked as the start of either a boundary or nonboundary edge. If the current edge flag is true when the vertex is specified, the vertex is marked as the start of a boundary edge. Otherwise, the vertex is marked as start of a nonboundary edge. glEdgeFlag sets the edge flag to true if flag is nonzero, false otherwise.

The vertices of connected triangles and connected quadriliterals are always marked as boundary, regardless of the value of the edge flag.

Boundary and nonboundary edge flags on vertices are significant only if GL_POLYGON_MODE is set to GL_POINT or GL_LINE. See glPolygonMode.

Initially, the edge flag is true.

NOTES

The current edge flag can be updated at any time. In particular, glEdgeFlag can be called between a call to glBegin and the corresponding call to glEnd.

ASSOCIATED GETS

glGet with argument GL_EDGE_FLAG

SEE ALSO

glBegin, glPolygonMode


back to the OpenGL index page


© 1995 Uwe Behrens. All rights reserved.