glNormalPointer Subroutine

OpenGL 1.2 for AIX: Reference Manual

glNormalPointer Subroutine

Purpose

Defines an array of normals.

Library

OpenGL C bindings library: libGL.a

C Syntax

void glNormalPointer( GLenum type,
   GLsizei stride,
   const GLvoid *pointer)

Description

The glNormalPointer subroutine specifies the location and data format of an array of normals to use when rendering. The type parameter 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 pointer 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 constructe 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.

Parameters

type	Specifies the the data type of each coordinate in the array. Symbolic constants GL_BYTE, GL_SHORT, GL_INT, GL_FLOAT, or GL_DOUBLE are accepted. The initial value is GL_FLOAT.
stride	Specifies the byte offset between consecutive normals. The initial value is 0.
pointer	Specifies a pointer to the first coordinate of the first normal in the array. The initial value is 0 (NULL pointer).

Notes

The glNormalPointer subroutine is available only if the GL version is 1.1 or greater.

The normal array is initially disabled and it won't be 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.

The glNormalPointer subroutine is typically implemented on the client side with no protocol.

Since the normal array parameters are client side state, they are not saved or restored by glPushAttrib and glPopAttrib. Use glPushClientAttrib and glPopClientAttrib instead.

The glNormalPointer subroutine is not included in display lists.

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

Related Information

The glArrayElement subroutine, glColorPointer subroutine, glDrawArrays subroutine, glDrawElements subroutine, glEdgeFlagPointer subroutine, glEnable subroutine, glGetPointerv subroutine, glIndexPointer subroutine, glNormalPointerListIBM subroutine, glPopClientAttrib subroutine, glPushClientAttrib subroutine, glTexCoordPointer subroutine, glVertexPointer subroutine.