HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 419

T gluTessProperty Is a boolean value ("value" should be set to GL_TRUE or GL_FALSE). When set to GL_TRUE, a set of closed contours separating the polygon interior and exterior are returned instead of a tessellation. Exterior contours are oriented CCW with respect to the normal; interior contours are oriented CW. The GLU_TESS_BEGIN and GLU_TESS_BEGIN_DATA callbacks use the type GL_LINE_LOOP for each contour. GLU_TESS_TOLERANCE Specifies a tolerance for merging features to reduce the size of the output. For example, two vertices that are very close to each other might be replaced by a single vertex. The tolerance is multiplied by the largest coordinate magnitude of any input vertex; this specifies the maximum distance that any feature can move as the result of a single merge operation. If a single feature takes part in several merge operations, the total distance moved could be larger. Feature merging is completely optional; the tolerance is only a hint. The implementation is free to merge in some cases and not in others, or to never merge features at all. The initial tolerance is 0. The current implementation merges vertices only if they are exactly coincident, regardless of the current tolerance. A vertex is spliced into an edge only if the implementation is unable to distinguish which side of the edge the vertex lies on. Two edges are merged only when both endpoints are identical. See Also gluGetTessProperty Chapter 18 419