func DepthRange(n float64, f float64) {
	syscall.Syscall(gpDepthRange, 2, uintptr(math.Float64bits(n)), uintptr(math.Float64bits(f)), 0)
}
func DepthRange(n float64, f float64) {
	syscall.Syscall(gpDepthRange, 2, uintptr(math.Float64bits(n)), uintptr(math.Float64bits(f)), 0)
}
func DepthRange ( n float64 , f float64 ) { syscall . Syscall ( gpDepthRange , 2 , uintptr ( math . Float64bits ( n ) ) , uintptr ( math . Float64bits ( f ) ) , 0 ) }
// specify mapping of depth values from normalized device coordinates to window coordinates
specify mapping of depth values from normalized device coordinates to window coordinates