Parameters flag Specifies the current edge flag value, either true or false.
Parameters flag Specifies a pointer to an array that contains a single Boolean element, which replaces the current edge flag value. 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 the start of a nonboundary edge. The vertices of connected triangles and connected quadrilaterals are always marked as boundary, regardless of the value of the edge flag. See glPolygonMode .