Defines a callback for a non-uniform rational B-spline (NURBS) object.
OpenGL C bindings library: libGL.a
void gluNurbsCallback(GLUnurbs* nurb, GLenum which, GLvoid (*CallBackFunc)())
The gluNurbsCallback subroutine is used to define a callback to be used by a NURBS object. If the specified callback is already defined, the existing definition is replaced. If the CallBackFunc parameter is null, then this callback will not get involked and the replaced data, if any, will be lost.
Except the error callback, these callbacks are used by NURBS tessellator (when GLU_NURBS_MODE is set to be GLU_NURBS_TESSELLATOR) to return back the OpenGL polygon primitives resulted from the tessellation. Note that there are two versions of each callback: one with a user data pointer and one without. If both versions for a particular callback are specified then the callback with the user data pointer will be used. Note that "userData" is a copy of the pointer that was specified at the last call to gluNurbsCallbackData.
The error callback function is effective no matter which value that GLU_NURBS_MODE is set to. All other callback functions are effective only when GLU_NURBS_MODE is set to GLU_NURBS_TESSELLATOR.
The legal callbacks are as follows:
| GLU_NURBS_BEGIN | The begin callback indicates the start of a primitive. The function takes a single argument of
type Glenum which can be one of GL_LINES, GL_LINE_STRIPS, GL_TRIANGLE_FAN, GL_TRIANGLE_STRIP, GL_TRIANGLES, or GL_QUAD_STRIP. The default begin callback function is null. The
function prototype for this callback looks like: void begin ( GLenum type ); |
| GLU_NURBS_BEGIN_DATA | The same as the GLU_NURBS_BEGIN callback except
that it takes an additional pointer argument. This pointer is a copy of the pointer that was
specified at the last call to gluNurbsCallbackData. The default callback
function is null. The function prototype for this callback function looks like: void beginData (GLenum type, void *userData); |
| GLU_NURBS_VERTEX | The vertex callback indicates a vertex of the primitive. The coordinates of the vertex are
stored in the parameter "vertex". All the generated vertices have dimension 3, that is,
Homogeneous coordinates have been transformed into affine coordinates. The default vertex callback
function is null. The function prototype for this callback function looks like: void vertex ( GLfloat *vertex ); |
| GLU_NURBS_VERTEX_DATA | The same as the GLU_NURBS_VERTEX callback except
that it takes an additional pointer argument. This pointer is a copy of the pointer that was
specified at the last call to gluNurbsCallbackData. The default callback
function is null. The function prototype for this callback function looks like: void vertexData ( GLfloat *vertex, void *userData ); |
| GLU_NURBS_NORMAL | The normal callback is invoked as the vertex normal is generated. The components of the normal
are stored in the parameter "normal". In the case of a NURBS curve, the callback function is
effective only when the user provides a normal map (GL_MAP1_NORMAL). In the case of a NURBS surface, if a normal map (GL_MAP2_NORMAL) is provided, then
the generated normal is computed from the normal map. If a normal map is not provided then a
surface normal is computed in a manner similar to that described for evaluators when GL_AUTO_NORMAL is enabled. The default normal callback function
is null. The function prototype for this callback function looks like: void normal ( GLfloat *normal ); |
| GLU_NURBS_NORMAL_DATA | The same as the GLU_NURBS_NORMAL callback except
that it takes an additional pointer argument. This
pointer is a copy of the pointer that was
specified at the last call to
gluNurbsCallbackData. The default callback
function is null. The function prototype for this
callback function looks like: void normalData ( GLfloat *normal, void *userData ); |
| GLU_NURBS_COLOR | The color callback is invoked as the color of a
vertex is generated. The components of the color
are stored in the parameter "color". This
callback is effective only when the user provides
a color map (GL_MAP1_COLOR_4 or GL_MAP2_COLOR_4).
"color" contains four components: R,G,B,A. The
default color callback function is null. The
prototype for this callback function looks like: void color ( GLfloat *color ); |
| GLU_NURBS_COLOR_DATA | The same as the GLU_NURBS_COLOR callback except
that it takes an additional pointer argument. This
pointer is a copy of the pointer that was
specified at the last call to
gluNurbsCallbackData. The default callback
function is null. The function prototype for this
callback function looks like: void colorData ( GLfloat *color, void *userData ); |
| GLU_NURBS_TEX_COORD | The texture callback is invoked as the texture
coordinates of a vertex are generated. These
coordinates are stored in the parameter
"texCoord". The number of texture coordinates can
be 1, 2, 3, or 4 depending on which type of
texture map is specified (GL_MAP*_TEXTURE_COORD_1,
GL_MAP*_TEXTURE_COORD_2, GL_MAP*_TEXTURE_COORD_3,
GL_MAP*_TEXTURE_COORD_4 where * can be either 1 or
2). If no texture map is specified, this callback
function will not be called. The default texture
callback function is null. The function prototype
for this callback function looks like: void texCoord ( GLfloat *texCoord ); |
| GLU_NURBS_TEXTURE_COORD_DATA | The same as the GLU_NURBS_TEX_COORD callback
except that it takes an additional pointer
argument. This pointer is a copy of the pointer
that was specified at the last call to
gluNurbsCallbackData. The default callback
function is null. The function prototype for this
callback function looks like: void texCoordData (GLfloat *texCoord, void *userData); |
| GLU_NURBS_END | The end callback is invoked at the end of a
primitive. The default end callback function is
null. The function prototype for this callback
function looks like:
void end ( void ); |
| GLU_NURBS_END_DATA | The same as the GLU_NURBS_TEX_COORD callback
except that it takes an additional pointer
argument. This pointer is a copy of the pointer
that was specified at the last call to
gluNurbsCallbackData. The default callback
function is null. The function prototype for this
callback function looks like:
void endData ( void *userData ); |
| GLU_NURBS_ERROR | The error function is called when an error is encountered. Its single argument is of type GLenum, and it indicates the specific error that occurred. There are 37 errors unique to NURBS named GLU_NURBS_ERROR1 through GLU_NURBS_ERROR37. Character strings describing these errors can be retrieved with gluErrorString. |
| /usr/include/GL/gl.h | Contains C language constraints, variable type definitions, and ANSI function prototypes for OpenGL. |
The gluErrorString subroutine, gluNewNurbsRenderer subroutine gluNurbsCallbackData subroutine gluNurbsProperty subroutine .