%《MATLAB在電子信息課程中的應用》第二章第五節演示程序二q252
% 三維繪圖和屏幕控制
% 電子工業出版社出版  陳懷琛 吳大正 高西全合著 2001年10月

clf
disp('三維曲線'),echo on
pause, z=0:0.1:4*pi;x=cos(z);y=sin(z);plot3(x,y,z,'linewidth',2)
pause,text(0,0,0,'*')

disp('三維曲面')
pause, x=-8:0.5:8;y=x';
X=ones(size(y))*x; %33*33陣
Y=y*ones(size(x)); %33*33陣
pause,subplot(1,2,1),plot(X,Y),
pause,subplot(1,2,2),plot(Y,X),
pause,subplot(1,1,1), R=sqrt(X.^2+Y.*Y); z=sin(R)./R; mesh(z)
%直接生成網格點
[X,Y]=meshgrid(-8:0.5:8,-8:0.5:8);
pause,subplot(1,2,1),plot(X,Y),
pause,subplot(1,2,2),plot(Y,X),
pause,disp('去掉分母為0點') 
figure(1)
pause,R=sqrt(X.^2+Y.*Y)+eps; z=sin(R)./R; mesh(z)
pause,R=abs(X)+abs(Y)+eps; z1=sin(R)./R; figure(2),mesh(z1)
pause,title('R=abs(x)+abs(y) sin(R)/R')
%pause,text(10,30,1.1,'R=abs(X)+abs(Y),z=sin(R)./R'),view(20,0),
pause,disp('屏幕分割')
pause,disp('坐標設定')
pause,subplot(2,2,1),R=sqrt(X.^2+Y.*Y); z=sin(R)./R; meshc(z)
pause,title('meshc(z),shading flat'),shading flat
pause,subplot(2,2,2), R=sqrt(X.^2+Y.*Y)+eps; z=sin(R)./R;meshz(z)
pause,title('meshz(z),shading interp'),shading interp
pause,subplot(2,2,3), R=abs(X)+abs(Y)+eps; z1=sin(R)./R; surfc(z1)
pause,title('surfc(z1),shading flat'),shading flat,
%colormap(gray)
pause,subplot(2,2,4); surfl(z1),view(20,0)
pause,title('surfl(z1),view(20,0)')