HP b2600 Reference Manual page 415

T
gluTessCallback
GLU_TESS_ERROR
The error callback is called when an error is encountered. The one argument is of type
GLenum; it indicates the specific error that occurred and will be set to one of
GLU_TESS_MISSING_BEGIN_POLYGON, GLU_TESS_MISSING_END_POLYGON,
GLU_TESS_MISSING_BEGIN_CONTOUR, GLU_TESS_MISSING_END_CONTOUR,
GLU_TESS_COORD_TOO_LARGE, GLU_TESS_NEED_COMBINE_CALLBACK.
Character strings describing these errors can be retrieved with the gluErrorString call.
The function prototype for this callback is:
void error(GLenum errno);
The GLU library will recover from the first four errors by inserting the missing call(s).
GLU_TESS_COORD_TOO_LARGE indicates that some vertex coordinate exceeded the
predefined constant GLU_TESS_MAX_COORD in absolute value, and that the value
has been clamped. (Coordinate values must be small enough so that two can be
multiplied together without overflow.)
GLU_TESS_NEED_COMBINE_CALLBACK indicates that the tessellation detected an
intersection between two edges in the input data, and the GLU_TESS_COMBINE or
GLU_TESS_COMBINE_DATA callback was not provided. No output is generated.
GLU_TESS_ERROR_DATA
The same as the GLU_TESS_ERROR callback except that it takes an additional pointer
argument. This pointer is identical to the opaque pointer provided when
gluTessBeginPolygon was called. The function prototype for this callback is:
void errorData(GLenum errno, void *polygon_data);
See Also
glBegin,
glEdgeFlag,
glVertex,
gluNewTess,
gluErrorString,
gluTessVertex,
gluTessBeginPolygon,
gluTessBeginContour,
gluTessProperty,
gluTessNormal
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Chapter 18