GLNORMALPOINTER

Section: Misc. Reference Manual Pages (3G)
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NAME

glNormalPointer - define an array of normals

C SPECIFICATION

void glNormalPointer( GLenum type,


                        GLsizei stride,
                        const GLvoid *ptr )

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PARAMETERS

type: Specifies the data type of each coordinate in the array. Symbolic 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