mirror of
git://projects.qi-hardware.com/openwrt-packages.git
synced 2024-11-05 18:03:44 +02:00
130 lines
3.1 KiB
Lua
130 lines
3.1 KiB
Lua
--[[ $Id: x27.lua 9526 2009-02-13 22:06:13Z smekal $
|
|
|
|
Drawing "spirograph" curves - epitrochoids, cycolids, roulettes
|
|
|
|
Copyright (C) 2009 Werner Smekal
|
|
|
|
This file is part of PLplot.
|
|
|
|
PLplot is free software you can redistribute it and/or modify
|
|
it under the terms of the GNU General Library Public License as published
|
|
by the Free Software Foundation either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
PLplot 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 Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public License
|
|
along with PLplot if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
--]]
|
|
|
|
-- initialise Lua bindings for PLplot examples.
|
|
dofile("plplot_examples.lua")
|
|
|
|
|
|
function cycloid()
|
|
-- TODO
|
|
end
|
|
|
|
|
|
function spiro( params )
|
|
NPNT = 20000
|
|
xcoord = {}
|
|
ycoord = {}
|
|
|
|
-- Fill the coordinates
|
|
windings = params[4]
|
|
steps = math.floor(NPNT/windings)
|
|
dphi = 8*math.acos(-1)/steps
|
|
|
|
xmin = 0 -- This initialisation is safe!
|
|
xmax = 0
|
|
ymin = 0
|
|
ymax = 0
|
|
|
|
for i = 1, windings*steps+1 do
|
|
phi = (i-1) * dphi
|
|
phiw = (params[1]-params[2])/params[2]*phi
|
|
xcoord[i] = (params[1]-params[2])*math.cos(phi) + params[3]*math.cos(phiw)
|
|
ycoord[i] = (params[1]-params[2])*math.sin(phi) - params[3]*math.sin(phiw)
|
|
|
|
if xmin>xcoord[i] then xmin = xcoord[i] end
|
|
if xmax<xcoord[i] then xmax = xcoord[i] end
|
|
if ymin>ycoord[i] then ymin = ycoord[i] end
|
|
if ymax<ycoord[i] then ymax = ycoord[i] end
|
|
end
|
|
|
|
if (xmax-xmin)>(ymax-ymin) then
|
|
scale = xmax - xmin
|
|
else
|
|
scale = ymax - ymin
|
|
end
|
|
xmin = -0.65*scale
|
|
xmax = 0.65*scale
|
|
ymin = -0.65*scale
|
|
ymax = 0.65*scale
|
|
|
|
pl.wind(xmin, xmax, ymin, ymax)
|
|
|
|
pl.col0(1)
|
|
pl.line(xcoord, ycoord)
|
|
end
|
|
|
|
|
|
----------------------------------------------------------------------------
|
|
-- main
|
|
--
|
|
-- Generates two kinds of plots:
|
|
-- - construction of a cycloid (animated)
|
|
-- - series of epitrochoids and hypotrochoids
|
|
----------------------------------------------------------------------------
|
|
|
|
-- R, r, p, N
|
|
params = {
|
|
{ 21, 7, 7, 3 }, -- Deltoid
|
|
{ 21, 7, 10, 3 },
|
|
{ 21, -7, 10, 3 },
|
|
{ 20, 3, 7, 20 },
|
|
{ 20, 3, 10, 20 },
|
|
{ 20, -3, 10, 20 },
|
|
{ 20, 13, 7, 20 },
|
|
{ 20, 13, 20, 20 },
|
|
{ 20,-13, 20, 20 } }
|
|
|
|
-- plplot initialization
|
|
|
|
-- Parse and process command line arguments
|
|
pl.parseopts(arg, pl.PL_PARSE_FULL)
|
|
|
|
-- Initialize plplot
|
|
pl.init()
|
|
|
|
-- Illustrate the construction of a cycloid
|
|
cycloid()
|
|
|
|
-- Loop over the various curves
|
|
-- First an overview, then all curves one by one
|
|
|
|
pl.ssub(3, 3) -- Three by three window
|
|
|
|
for i = 1, 9 do
|
|
pl.adv(0)
|
|
pl.vpor(0, 1, 0, 1)
|
|
spiro(params[i])
|
|
end
|
|
|
|
pl.adv(0)
|
|
pl.ssub(1, 1) -- One window per curve
|
|
|
|
for i = 1, 9 do
|
|
pl.adv(0)
|
|
pl.vpor(0, 1, 0, 1)
|
|
spiro(params[i])
|
|
end
|
|
|
|
-- Don't forget to call plend() to finish off!
|
|
pl.plend()
|