func Frustum(left float64, right float64, bottom float64, top float64, zNear float64, zFar float64) {
	syscall.Syscall6(gpFrustum, 6, uintptr(math.Float64bits(left)), uintptr(math.Float64bits(right)), uintptr(math.Float64bits(bottom)), uintptr(math.Float64bits(top)), uintptr(math.Float64bits(zNear)), uintptr(math.Float64bits(zFar)))
}
func Frustum(left float64, right float64, bottom float64, top float64, zNear float64, zFar float64) {
	syscall.Syscall6(gpFrustum, 6, uintptr(math.Float64bits(left)), uintptr(math.Float64bits(right)), uintptr(math.Float64bits(bottom)), uintptr(math.Float64bits(top)), uintptr(math.Float64bits(zNear)), uintptr(math.Float64bits(zFar)))
}
func Frustum ( left float64 , right float64 , bottom float64 , top float64 , zNear float64 , zFar float64 ) { syscall . Syscall6 ( gpFrustum , 6 , uintptr ( math . Float64bits ( left ) ) , uintptr ( math . Float64bits ( right ) ) , uintptr ( math . Float64bits ( bottom ) ) , uintptr ( math . Float64bits ( top ) ) , uintptr ( math . Float64bits ( zNear ) ) , uintptr ( math . Float64bits ( zFar ) ) ) }
// multiply the current matrix by a perspective matrix
multiply the current matrix by a perspective matrix