function trigart(symmetry,randomness,triangulate,trigsize,symcolor);
%TRIGART Create an artistic drawing made of interlocking polygons.
%
% Parameters are symmetry,randomness,triangulate,size.
% symmetry : 4 to 10, default 5.
% randomness : 0 to 20, default 10.
% triangulate : 0 to 1, default 1.
% trigsize : 5 to 10, default 6.
% symcolor : 0 to 1, default 0.
%
% TRIGART with no arguments produces random symmetries and colors.
% TRIGART(5,0,0,6,0) makes symmetry degree 5, size 6 figure.
% TRIGART(5,4,0,6,0) omits rand * 4 lines.
% TRIGART(5,4,1,6,0) trianglates all polygons.
% TRIGART(5,4,1,8,0) creates a size 8 figure.
% TRIGART(5,4,1,8,1) colors symmetrically.
%
% Written for Matlab 5.x
% by Jim Clark E-Mail jclark01@pacbell.net
% $Revision: 1.0 $ $Date: 1999/08/08 15:00:00 $
global cmx1 cmx2 cmx3 cmy1 cmy2 cmy3 X1 Y1 hm;
cmx1 = []; cmx2 = []; cmy3 = [];
cmy1 = []; cmy2 = []; cmy3 = [];
X1 = []; Y1 = []; color = rand;
count = 0;
cla;
%symcolor=0;
%hold on;
icolor = rand * 128 ;
set (gcf,'Renderer','painters');
h = 1;
figure(h);
set(h,'DoubleBuffer','on');
%axis([0 9 4 13]);
if nargin == 0
symmetry = fix(3+7 * rand + .5);
randomness = fix(20 * rand);
triangulate = fix(rand + .5);
trigsize = fix(5.5+rand*5);
symcolor = 0;
elseif nargin == 1
symcolor = 0;
randomness = 10; triangulate = 1; trigsize = 5;
elseif nargin == 2
symcolor = 0;
triangulate = 1; trigsize = 5;
elseif nargin == 3
symcolor = 0;
trigsize = 5;
elseif nargin == 4
symcolor = 0;
elseif nargin > 5
error('Incorrect number of arguments')
end
if symmetry > 10
symmetry = 10;
elseif symmetry < 3
symmetry = 3;
end
if randomness > 30
randomness = 30
elseif randomness < 0
randomness = 0
end
if triangulate ~= 0 & triangulate ~= 1
triangulate = 1;
end
if trigsize > 30
trigsize = 30;
elseif trigsize < 1
trigsize = 1;
end
if symcolor ~= 0
symcolor = 1;
end
halfmax = fix(trigsize/2);
factor = 2;
if (symmetry == 4)
factor = 1;
end
step = 1;
for t=0:1:symmetry-1 %1
phi = ((t*pi*factor)+(pi*5*symmetry/180))/symmetry;
%pp = phi*180/pi
vx(t+1) = cos(phi);
vy(t+1) = sin(phi);
mm(t+1) = vy(t+1)/vx(t+1);
for r=0:1:trigsize-1 %2
y1 = vy(t+1)*(t*0.1132) - vx(t+1)*(r-halfmax); % offset
x1 = vx(t+1)*(t*0.2137) + vy(t+1)*(r-halfmax);
b(t+1,r+1) = y1 - mm(t+1)*x1; % intercept
end %2
end %1
% t is 1st direction, r is 2nd. look for intersection between
% pairs of lines in these two directions. (will be x0,y0)
% color = 0.2;
themax = fix(trigsize-1);
themin = fix(themax/2);
for minmin=0:step:themax %1 for
rad1 = minmin*minmin;
rad2 = (minmin+step)*(minmin+step);
for n=1:1:themax-1 %2 for
for m=1:1:themax-1 %3 for
rad = (n-themin)*(n-themin)+(m-themin)*(m-themin);
if rad >= rad1 & rad < rad2 %4
for t=0:1:symmetry-2 %5 for
for r=t+1:1:symmetry-1 %6 for
x0 = (b(t+1,n+1) - b(r+1,m+1))/(mm(r+1)-mm(t+1));
y0 = mm(t+1)*x0 + b(t+1,n+1);
flag = 0;
for i=0:1:symmetry-1 %7 for
if i ~= t & i ~= r %8
dx = -x0*vy(i+1)+(y0-b(i+1,1))*vx(i+1);
index(i+1) = fix(-dx);
if ((index(i+1)>(trigsize-3))|(index(i+1)<1)) %9
flag=1;
end %9
end %8
end %7
if flag==0 %7
index(t+1) = n-1;
index(r+1) = m-1;
x0 = 0;
y0 = 0;
for i=0:1:symmetry-1 %8
x0 = x0 + vx(i+1)*index(i+1);
y0 = y0 + vy(i+1)*index(i+1);
end %8
if symcolor == 0
color = color + rand*64;
while (color > 64)
color = color - 64;
end
elseif (symcolor==1) %8
%dot product
color=icolor*abs(vx(t+1)*vx(r+1)+vy(t+1)*vy(r+1));
while (color > 64)
color = color - 64;
end
end %9
pplot(x0,y0,0, color,randomness,triangulate,count);
x0 = x0 + vx(t+1);
y0 = y0 + vy(t+1);
pplot(x0,y0,1,color,randomness,triangulate,count);
x0 = x0 + vx(r+1);
y0 = y0 + vy(r+1);
pplot(x0,y0,1,color,randomness,triangulate,count);
x0 = x0 - vx(t+1);
y0 = y0 - vy(t+1);
pplot(x0,y0,1,color,randomness,triangulate,count);
x0 = x0 - vx(r+1);
y0 = y0 - vy(r+1);
pplot(x0,y0,2,color,randomness,triangulate,count);
end %7
end %6
end %5
end %4
end %3
end %2
end %1
'Trigart Calculations Complete'
function pplot(cmx,cmy,plotflag, color,randomness,triangulate,count)
global cmx1 cmx2 cmx3 cmy1 cmy2 cmy3 X1 Y1 hm;
%drawnow;
xx = cmx;
yy = cmy;
a = -pi*5/180;
cmx = xx * cos(a) - sin(a)*yy;
cmy = xx * sin(a) + cos(a)*yy;
if plotflag < 1 % 0=start line; 1=lineto; 2=endpoint
cmx1 = cmx; cmx2 = cmx; cmx3 = cmx;
cmy1 = cmy; cmy2 = cmy; cmy3 = cmy;
count = 0;
else %1
if triangulate == 1
cmx3 = []; cmy3 = []; cmz3 = [];
else
cmz3 = 0;
end
count = count + 1;
if count>rand*randomness
X1 = [cmx cmx1 cmx2 cmx3];
Y1 = [cmy cmy1 cmy2 cmy3];
hm = patch(X1,Y1,color);
set (hm, 'CDataMapping','direct');
count = 0;
end
cmx3 = cmx2; cmx2 = cmx1; cmx1 = cmx;
cmy3 = cmy2; cmy2 = cmy1; cmy1 = cmy;
end
