func IndexPointer(xtype uint32, stride int32, pointer unsafe.Pointer) {
	syscall.Syscall(gpIndexPointer, 3, uintptr(xtype), uintptr(stride), uintptr(pointer))
}
func IndexPointer(xtype uint32, stride int32, pointer unsafe.Pointer) {
	syscall.Syscall(gpIndexPointer, 3, uintptr(xtype), uintptr(stride), uintptr(pointer))
}
func IndexPointer ( xtype uint32 , stride int32 , pointer unsafe . Pointer ) { syscall . Syscall ( gpIndexPointer , 3 , uintptr ( xtype ) , uintptr ( stride ) , uintptr ( pointer ) ) }
// define an array of color indexes
define an array of color indexes