dbordv.m

来自「采用MATLAB编写B样条绘制程序」· M 代码 · 共 30 行

function linePoint=Dbordv(b,k,style)
nb=length(b);
[T,R]=Shiliang(b,k,style)
np=1;ni=1;
d=zeros(nb,2,k+1);
d(:,:,1)=b;
u=0.0;
denom=0.0;alpha=0.0;
linePoint=zeros(nb*np,2);
% for ui=0:(nb*np-1)    
%       u=(ui)/(nb*np-1);   
         u=0.5
      i=Knot_i(u,k,T,R,style);
      if(~(i>0))
      else
         for nl=2:k+1
           for j=(i-k):(i-nl+1)
             du=Knot_var(j+k+1,T,R)-Knot_var(j+nl-1,T,R);
             if(abs(du)==0.0) alpha=0.0;
             else                
               alpha=abs((u-Knot_var(j+nl-1,T,R))/du)
             end  %endif              
             d(j,:,nl)=(1.0-alpha)*d(j,:,nl-1)+alpha*d(j+1,:,nl-1)
           end %endfor
         end  %endfor
%         linePoint(ui+1,:)=d(i-k,:,k+1); 
      end %endif
%  end %endfor