GLNORMALPOINTER(3gl)
NAME
glNormalPointer - define an array of normals
C SPECIFICATION
- void glNormalPointer( GLenum type,
- GLsizei stride,
const GLvoid *ptr )
PARAMETERS
- type Specifies the data type of each coordinate in the array. Sym
- bolic constants GL_BYTE, GL_SHORT, GL_INT, GL_FLOAT, and GL_DOUBLE are accepted. The initial value is GL_FLOAT.
- stride Specifies the byte offset between consecutive normals. If
- stride is 0- the initial value-the normals are understood to be tightly packed in the array. The initial value is 0.
- ptr Specifies a pointer to the first coordinate of the first normal
- in the array. The initial value is 0.
DESCRIPTION
glNormalPointer specifies the location and data of an array of normals
to use when rendering. type specifies the data type of the normal
coordinates and stride gives the byte stride from one normal to the
next, allowing vertices and attributes to be packed into a single array
or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see glInterleavedArrays.) When a normal
array is specified, type, stride, and ptr are saved as client-side
state.
To enable and disable the normal array, call glEnableClientState and
glDisableClientState with the argument GL_NORMAL_ARRAY. If enabled, the
normal array is used when glDrawArrays, glDrawElements, or
glArrayElement is called.
Use glDrawArrays to construct a sequence of primitives (all of the same
type) from prespecified vertex and vertex attribute arrays. Use
glArrayElement to specify primitives by indexing vertices and vertex
attributes and glDrawElements to construct a sequence of primitives by
indexing vertices and vertex attributes.
NOTES
glNormalPointer is available only if the GL version is 1.1 or greater.
The normal array is initially disabled and isn't accessed when glArrayElement, glDrawElements, or glDrawArrays is called.
Execution of glNormalPointer is not allowed between glBegin and the
corresponding glEnd, but an error may or may not be generated. If an
error is not generated, the operation is undefined.
glNormalPointer is typically implemented on the client side.
Since the normal array parameters are client-side state, they are not saved or restored by glPushAttrib and glPopAttrib. Use glPushClientAttrib and glPopClientAttrib instead.
ERRORS
GL_INVALID_ENUM is generated if type is not an accepted value.
GL_INVALID_VALUE is generated if stride is negative.
ASSOCIATED GETS
glIsEnabled with argument GL_NORMAL_ARRAY glGet with argument GL_NORMAL_ARRAY_TYPE glGet with argument GL_NORMAL_ARRAY_STRIDE glGetPointerv with argument GL_NORMAL_ARRAY_POINTER