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gluNextContour
Chapter 12
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gluNextContour
gluNextContour: mark the beginning of another contour.
C Specification
void gluNextContour(
GLUtesselator* tess,
GLenum type)
Parameters
tess Specifies the tessellation object (created with gluNewTess).
type Specifies the type of the contour being defined. Valid values are
GLU_EXTERIOR, GLU_INTERIOR, GLU_UNKNOWN, GLU_CCW,
and GLU_CW.
Description
gluNextContour is used in describing polygons with multiple contours. After the first
contour has been described through a series of gluTessVertex calls, a gluNextContour
call indicates that the previous contour is complete and that the next contour is about to
begin.
Another series of gluTessVertex calls is then used to describe the new contour. This
process can be repeated until all contours have been described.
type defines what type of contour follows. The legal contour types are as follows:
GLU_EXTERIOR
An exterior contour defines an exterior boundary of the polygon.
GLU_INTERIOR
An interior contour defines an interior boundary of the polygon (such as a hole).
GLU_UNKNOWN
An unknown contour is analyzed by the library to determine if it is interior or exterior.
GLU_CCW, GLU_CW
The first GLU_CCW or GLU_CW contour defined is considered to be exterior. All other
contours are considered to be exterior if they are oriented in the same direction
(clockwise or counterclockwise) as the first contour, and interior if they are not.
If one contour is of type GLU_CCW or GLU_CW, then all contours must be of the same
type (if they are not, then all GLU_CCW and GLU_CW contours will be changed to
GLU_UNKNOWN).
Note that there is no real difference between the GLU_CCW and GLU_CW contour
types.
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