When a normal array is specified, type , stride , pointer and ptrstride are saved as client side state. Instead, it causes the first array element of each array to be used for each vertex. Also, a negative value can be used for stride, which allows the user to move through each array in reverse order. The normal array is initially disabled. See the descriptions of these routines for more information on their use.
Parameters type Specifies the data type of each normal component in the array.
The initial value is 0. The initial value is 0. Execution of glNormalPointerListIBM 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 glNormalPointerListIBM subroutine is typically implemented on the client side.