# Source code for boxes.generators.organpipe

```#!/usr/bin/env python3
# Copyright (C) 2013-2018 Florian Festi
#
# Based on pipecalc by Christian F. Coors
# https://github.com/ccoors/pipecalc
#
#   This program is free software: you can redistribute it and/or modify
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.

from math import *

from boxes import *

pitches = ['c', 'c#', 'd', 'd#', 'e', 'f', 'f#', 'g', 'g#', 'a', 'a#' ,'b']

pressure_units = { 'Pa' : 1.0,
'mBar' : 100.,
'mmHg' : 133.322,
'mmH2O' : 9.80665,
}

[docs]class OrganPipe(Boxes): # Change class name!
"""Rectangular organ pipe based on pipecalc"""

ui_group = "Unstable" # see ./__init__.py for names

def getFrequency(self, pitch, octave, base_freq=440):
steps = pitches.index(pitch) + (octave-4)*12 - 9
return base_freq * 2**(steps/12.)

steps = pitches.index(pitch) + (octave-2)*12 + intonation
return 0.5 * 0.15555 * 0.957458**steps

def getAirSpeed(self, wind_pressure, air_density=1.2):
return (2.0 * (wind_pressure / air_density))**.5

def __init__(self) -> None:
Boxes.__init__(self)

surroundingspaces=1.0)

"""
air_temperature: f64,
"""
# Add non default cli params if needed (see argparse std lib)
"--pitch",  action="store", type=str, default="c",
choices=pitches,
help="pitch")
"--octave",  action="store", type=int, default=2,
help="Octave in International Pitch Notation (2 == C)")
"--intonation",  action="store", type=float, default=2.0,
help="Intonation Number. 2 for max. efficiency, 3 max.")
"--mouthratio",  action="store", type=float, default=0.25,
help="mouth to circumference ratio (0.1 to 0.45). Determines the width to depth ratio")
"--cutup",  action="store", type=float, default=0.3,
help="Cutup to mouth ratio")
"--mensur",  action="store", type=int, default=0,
help="Distance in halftones in the Normalmensur by Töpfer")
"--windpressure",  action="store", type=float, default=588.4,
help="uses unit selected below")
"--windpressure_units",  action="store", type=str, default='Pa',
choices=pressure_units.keys(),
help="in Pa")
"--stopped",  action="store", type=boolarg, default=False,
help="pipe is closed at the top")

def render(self):
t = self.thickness
f = self.getFrequency(self.pitch, self.octave, 440)

self.windpressure *= pressure_units.get(self.windpressure_units, 1.0)

speed_of_sound = 343.6 # XXX util::speed_of_sound(self.air_temperature); // in m/s
air_density = 1.2
air_speed = self.getAirSpeed(self.windpressure, air_density)

i = self.intonation
circumference = pi * radius * 2.0
mouth_width = circumference * self.mouthratio
mouth_height = mouth_width * self.cutup
mouth_area = mouth_height * mouth_width
pipe_depth = cross_section / mouth_width
base_length = max(mouth_width, pipe_depth)

jet_thickness = (f**2 * i**2 * (.01 * mouth_height)**3) / air_speed**2
sound_power = (0.001 * pi * (air_density / speed_of_sound) * f**2
* (1.7 * (jet_thickness * speed_of_sound * f * mouth_area * mouth_area**.5)**.5)**2)

air_consumption_rate = air_speed * mouth_width * jet_thickness * 1E6

wavelength = speed_of_sound / f * 1000

if self.stopped:
theoretical_resonator_length = wavelength / 4.0
resonator_length = (-0.73 * (f * cross_section *1E-6 - 0.342466 * speed_of_sound * mouth_area**.5 * 1E-3)
/ (f * mouth_area**.5 * 1E-3))
else:
theoretical_resonator_length = wavelength / 2.0
resonator_length = (-0.73 * (f * cross_section * 1E-6 + 0.465753 * f * mouth_area**.5 * cross_section**.5 * 1E-6 - 0.684932 * speed_of_sound * mouth_area**.5 * 1E-3)
/ (f * mouth_area**.5 * 1E-3)) * 1E3
air_hole_diameter = 2.0 * ((mouth_width * jet_thickness * 10.0)**.5 / pi)

total_length = resonator_length + base_length

e = ["f", "e",
edges.CompoundEdge(self, "fef", (resonator_length - mouth_height - 10*t, mouth_height + 10*t, base_length)), "f"]

self.rectangularWall(total_length, pipe_depth, e, callback=[
lambda: self.fingerHolesAt(base_length-0.5*t, 0, pipe_depth-jet_thickness)],
move="up")
self.rectangularWall(total_length, pipe_depth, e, callback=[
lambda: self.fingerHolesAt(base_length-0.5*t, 0, pipe_depth-jet_thickness)],
move="up")
self.rectangularWall(total_length, mouth_width, "FeFF", callback=[
lambda: self.fingerHolesAt(base_length-0.5*t, 0, mouth_width)],
move="up")
e = [edges.CompoundEdge(self, "EF", (t*10, resonator_length - mouth_height - t*10)), 'e',
edges.CompoundEdge(self, "FE", (resonator_length - mouth_height - t*10, t*10)), 'e']
self.rectangularWall(resonator_length - mouth_height, mouth_width, e, move="up")
self.rectangularWall(base_length, mouth_width, "FeFF", move="right")
self.rectangularWall(mouth_width, pipe_depth, "fFfF", callback=[
lambda:self.hole(mouth_width/2, pipe_depth/2, d=air_hole_diameter)], move="right")
self.rectangularWall(mouth_width, pipe_depth - jet_thickness, "ffef", move="right")

```