| Name |
| |
| EXT_object_space_tess |
| |
| Name Strings |
| |
| GLU_EXT_object_space_tess |
| |
| Version |
| |
| $Date: 1996/04/12 |
| |
| Number |
| |
| 75 |
| |
| Dependencies |
| |
| None |
| |
| Overview |
| |
| This extension adds two object space tessellation methods for GLU nurbs |
| surfaces. The existing tessellation methods GLU_PATH_LENGTH and |
| GLU_PARAMETRIC_ERROR are view dependent since the error tolerance is |
| measured in the screen space (in pixels), while the corresponding object |
| space tessellation methods are view independent in that the error tolerance |
| measurement is in the object space. |
| |
| |
| New Procedures and Functions |
| |
| None |
| |
| New Tokens |
| |
| Accepted by the <value> parameter of NurbsProperty: |
| |
| OBJECT_PARAMETRIC_ERROR_EXT 100208 |
| OBJECT_PATH_LENGTH_EXT 100209 |
| |
| Errors |
| |
| None |
| |
| Additions to the GLU Specification Version 1.2, Section 7.6 |
| |
| NURBS properties |
| ---------------- |
| |
| GLU_SAMPLING_METHOD specifies how a NURBS surface should be tessellated. |
| value may be set to one of GLU_PATH_LENGTH, GLU_PARAMETRIC_ERROR, |
| GLU_DOMAIN_DISTANCE, GLU_OBJECT_PATH_LENGTH_EXT, or GLU_OBJECT_PARAMETRIC_ERROR_EXT. |
| When set to |
| GLU_PATH_LENGTH, the surface |
| is rendered so that the maximum length, in pixels, of edges of the |
| tessellation polygons is no greater than what is specified by |
| GLU_SAMPLING_TOLERANCE. |
| GLU_PARAMETRIC_ERROR specifies that |
| the surface is rendered in such a way that the value specified by |
| GLU_PARAMETRIC_TOLERANCE describes the maximum distance, in pixels, |
| between the tessellation polygons and the surfaces they approximate. |
| GLU_DOMAIN_DISTANCE allows the users to specify, in parametric |
| coordinates, how many sample points per unit length are taken in u, v |
| dimension. |
| GLU_OBJECT_PATH_LENGTH_EXT is similar to GLU_PATH_LENGTH except that it is |
| view independent, that is, it specifies that the surface is rendered so that |
| the maximum length, in object space, of edges of the tessellation polygons |
| is no greater than what is specified by GLU_SAMPLING_TOLERANCE. |
| GLU_OBJECT_PARAMETRIC_ERROR_EXT is similar to GLU_PARAMETRIC_ERROR except |
| that it is view independent, that is, it specifies that |
| the surface is rendered in such a way that the value specified by |
| GLU_PARAMETRIC_TOLERANCE describes the maximum distance, in object space, |
| between the tessellation polygons and the surfaces they approximate. |
| The default value of GLU_SAMPLING_METHOD is GLU_PATH_LENGTH. |
| |
| GLU_SAMPLING_TOLERANCE specifies the maximum distance, in pixels or |
| in object space when the sampling method is set to GLU_PATH_LENGTH or |
| GLU_OBJECT_PATH_LENGTH_EXT. The default value for GLU_SAMPLING_TOLERANCE |
| is 50.0. |
| |
| GLU_PARAMETRIC_TOLERANCE specifies the maximum distance, in pixels or |
| in object space when the sampling method is set to GLU_PARAMETRIC_ERROR |
| or GLU_OBJECT_PARAMETRIC_ERROR_EXT. The default value for |
| GLU_PARAMETRIC_TOLERANCE is 0.5. |
| |
| |
| |
| |