I’m trying to write a simulation that will move a light source over the surface of an object, on each step measure the intensity of reflected light back to the light source.
Then plot the intensity from each point of the surface. With each step adding to the first plot. Thus building up a picture of the surface topography.
It is a bit messy if you can suggest a way to tidy up.
x = -10:0.25:10;
y = -10:0.25:10;
xlength=length(x);
ylength=length(y);
ymin=min(y);
ymax=max(y);
xmin=min(x);
xmax=max(x);
D=zeros(xlength);
[X,Y] = meshgrid(x,y);
z = 10-(X.^2)-(Y.^2)+5*sin(X);
rnd=rand(xlength);
c=randi(xlength);
d=randi(xlength);
s=1;
t=0;
for i=1:ylength
t=t+1;
for j=1:xlength
if s==c
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
elseif s==c+1
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
elseif s==c+2
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
elseif s==c+3
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
elseif s==(c+4)
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
else
D(s,t)=0;
end
s=s+1;
end
s=1;
end
z1=z -(D/20);
z2=z1-z;
s=0;
figure
surf(X,Y,z)
axis([xmin xmax ymin ymax])
xlabel('X')
ylabel('Y')
zlabel('Z')
for i=-10:2.5:10
hold on
light('position',[i,0,50])
surf(X,Y,z,'EdgeColor', 'none')
axis([xmin xmax ymin ymax])
drawnow
pause (1)
delete(findall(gcf,'Type','light'))
hold off
end
This is as far as I have got .
A code that does exactly what yours does: (thanks @Hoki for the help in simplifying the code even more)
clear;clc
x = -10:0.25:10;
y = -10:0.25:10;
xlength=length(x);
ylength=length(y);
ymin=min(y);
ymax=max(y);
xmin=min(x);
xmax=max(x);
[X,Y] = meshgrid(x,y);
z = 10-(X.^2)-(Y.^2)+5*sin(X);
%% plot!
figure
surf(X,Y,z,'EdgeColor', 'none','lineStyle','none') % taken out the linestyle because it looks cooler
axis([xmin xmax ymin ymax])
xlabel('X')
ylabel('Y')
zlabel('Z')
% Added repetitions and decreased step size, plus making it go forward and backward.
repetitions=4;
for jj=1:repetitions
hl = light('position',[-10,0,50]) ; %// create the light source
for i=-10:2.5:10
set(hl,'position',[i,0,50]) ; %// set the new light position
drawnow %// flush graphic pipeline
pause (0.1) %// let human user see something
end
delete(hl) %// delete the light source
end
This gives the following gif:
http://i.imgur.com/42ffYll.gifv
About the rest part of the code....
Remember that
if t==d
D(s,t)=z(s,t);
elseif t==d+1
D(s,t)=z(s,t);
elseif t==d+2
D(s,t)=z(s,t);
elseif t==d+3
D(s,t)=z(s,t);
elseif t==d+4
D(s,t)=z(s,t);
elseif t==d+5
D(s,t)=z(s,t);
else
D(s,t)=0;
end
is literally the same as:
if (t>=d && t<=d+5)
D(s,t)=z(s,t);
else
D(s,t)=0;
end
This should help you reduce the code. There is also vectorization.
you can do
D(s,(t>=d && t<=d+5))=z(s,(t>=d && t<=d+5)));
for all values of s... etc etc. Hope this gets you going ;)