%Lecture 33: Drawing 3D-objects

% sphere
[x,y,z] = sphere(10);
surf(x,y,z);
sphere(20);

% "cylinder" = rotation object
cylinder(30);
cylinder(30, 30);
% give the curve y = y(x)
x = 0:1:5 
y = [1 1 2 3 2 1] 
plot(x,y)
axis off
cylinder(y, 20);
cylinder([0,1,2,3,4,3,3,3,5,6], 20);

% SPLINES: draw a car profile

x = [1 1.8 4 4.8 6.8 7.6 8.8 9.4];
y = [1.5 2 2.1 2.5 2.5 2.2 2.0 1.5];
plot(x,y)
axis off
xx = 1:0.2:9.4;
yy = spline(x,y,xx);
size(xx)
plot(x,y,'o',xx, yy)
hold on
% wheels
t = 0:0.1:2*pi;
plot(2.5+0.5*cos(t),1.5+0.5*sin(t));
plot(8.5+0.5*cos(t),1.5+0.5*sin(t));
for k = 0.1:0.05:0.9
plot(8.5+0.5*k*cos(t),1.5+0.5*k*sin(t));
end;
size(t)
t(63)
for k = 0.1:0.05:0.9
plot(2.5+0.5*k*cos(t),1.5+0.5*k*sin(t));
end;
hold off
% 3D modeling: polyhedra
x1 = [0 1 1]; y1 = [0 0 1]; z1 = [0 0 0];
patch(x1,y1,z1,'r')
view(3),grid
hold on
patch([0 1 0], [0 1 1], [0 0 1], 'g')
% a polyhedron
v = [0 0 0
1 1 0
1 -1 0
1 0 -1
1 0 1
1 0 0
];
f = [1 2 6
1 6 3
14 6
1 6 5];
f = [1 2 6
1 6 3
1 4 6
1 6 5];
patch('vertices', v, 'faces', f, 'facecolor', 'b')
g = [2 5 6];
patch('vertices', v, 'faces', g, 'facecolor', 'r')

%Hint: #5, p.5.6
x
y
hold off
cylinder(y,20)
yy
cylinder(yy,20)