function TextBall

% 旋转的文字球：滑动鼠标，控制文字球的旋转方向

% CopyRight：xiezhh(谢中华)

% 写于2012.11.11(光棍节)

t1 = linspace(0,2*pi,21);

t1(end) = [];

t2 = linspace(-pi/2,pi/2,20);

[Theta, Pho] = meshgrid(t1,t2);

x = cos(Pho).*cos(Theta);

y = cos(Pho).*sin(Theta);

z = sin(Pho);

[data,str] = xlsread('百家姓.xls');

str = str';

str = str(1:400);

ColorMat = [jet(100);gray(100)];

id = randi(200,1,400);

surf([x,x(:,1)]/8,[y,y(:,1)]/8,[z,z(:,1)]/8,'FaceColor','r','EdgeColor','None');

camlight;

hold on;

arrayfun(@(i)text(x(i),y(i),z(i),str{i},'Color',ColorMat(id(i),:)),1:400);

axis([-1.1,1.1,-1.1,1.1,-1.1,1.1]);

axis vis3d off;

xyz1 = [-7,-7,7];  % 当前视点

set(gca,'CameraPositionMode','manual','CameraPosition',xyz1);

set(gcf,'WindowButtonMotionFcn',@MyWindowButtonMotionFcn);

[az,el,R] = cart2sph(xyz1(1),xyz1(2),xyz1(3));

setappdata(gcf,'xyz_old',xyz1);

set(gca,'Interruptible','off');

set(gcf,'Interruptible','off','BusyAction','cancel');

hold off;

%%-------------------------------------------------------------------------

%  子函数1

%%-------------------------------------------------------------------------

function MyWindowButtonMotionFcn(hObject, eventdata)

xyz2 = getappdata(gcf,'xyz_old');  % 当前视点

CP_new = get(gca,'CurrentPoint');

xyz3 = CP_new(1,:);  % 当前坐标点

xyz3 = R*xyz3/sqrt(xyz3*xyz3');

[cy,sy,cz,sz] = CoordinateRotation1(xyz2,xyz3);

[Theta1,Theta2] = CoordinateRotation2(cy,sy,cz,sz,xyz2,xyz3);

for t = nlinspace(Theta1,Theta2+2*pi*sign(Theta2-Theta1),100,4)

xyzi = CoordinateRotation3(cy,sy,cz,sz,t);

set(gca,'CameraPosition',xyzi);

drawnow;

end

setappdata(gcf,'xyz_old',xyz3);

end

%%-------------------------------------------------------------------------

%  子函数2

%%-------------------------------------------------------------------------

function [cy,sy,cz,sz] = CoordinateRotation1(XYZ1,XYZ2)

p = cross(XYZ1,XYZ2);  % 法线方向向量

dx = p(1);dy = p(2);dz = p(3);

% 计算法线与y轴正向夹角余弦，法线与y轴正向夹角正弦负值

den1 = sqrt(dx^2 + dy^2);

cy = dy/den1;

cy(den1 == 0) = 1;

sy = -dx/den1;

sy(den1 == 0) = 0;

% 计算法线与z轴正向夹角余弦，法线与z轴正向夹角正弦负值

den2 = sqrt(dx^2 + dy^2 + dz^2);

cz = dz/den2;

cz(den2 == 0) = 1;

sz = -sqrt(dx^2 + dy^2)/den2;

sz(den2 == 0) = 0;

end

%%-------------------------------------------------------------------------

%  子函数3

%%-------------------------------------------------------------------------

function [Theta1,Theta2] = CoordinateRotation2(cy,sy,cz,sz,XYZ1,XYZ2)

% 通过坐标旋转计算当前视点与当前坐标点对应的角度

% XYZ1：当前视点； XYZ2：当前坐标点

fun = @(x)[x(1)*cy + x(2)*sy;-x(1)*cz*sy + x(2)*cz*cy + x(3)*sz];

XYZ1 = fun(XYZ1);

XYZ2 = fun(XYZ2);

Theta1 = atan2(XYZ1(2),XYZ1(1));

Theta2 = atan2(XYZ2(2),XYZ2(1));

Theta1 = Theta1*(Theta1>=0) + (2*pi+Theta1)*(Theta1<0);

Theta2 = Theta2*(Theta2>=0) + (2*pi+Theta2)*(Theta2<0);

end

%%-------------------------------------------------------------------------

%  子函数4

%%-------------------------------------------------------------------------

function XYZ = CoordinateRotation3(cy,sy,cz,sz,t)

% 通过坐标旋转计算视点坐标

x0 = cos(t);

y0 = sin(t);

% 计算三维管道型几何体的网格数据X，Y和Z

XYZ(1) = R*(x0*cy - y0*(cz*sy));

XYZ(2) = R*(x0*sy + y0*(cz*cy));

XYZ(3) = R*y0*sz;

end

%%-------------------------------------------------------------------------

%  子函数5

%%-------------------------------------------------------------------------

function yd = nlinspace(x1,x2,n,m)

% 产生不等间隔向量:y(n) = a*n^(1/m) + b,  y(1) = x1,  y(n) = x2

xd = 1:n;

a = (x2-x1)/(n^(1/m)-1);

b = x1-a;

yd = a*xd.^(1/m)+b;

end

endfunction TextBall

% 旋转的文字球：滑动鼠标，控制文字球的旋转方向

% CopyRight：xiezhh(谢中华)

% 写于2012.11.11(光棍节)

t1 = linspace(0,2*pi,21);

t1(end) = [];