function [newno,newfc]=remeshsurf(node,face,opt)
%
% [newno,newfc]=remeshsurf(node,face,opt)
%
% remesh a triangular surface and the output is guaranteed to be
% free of self-intersecting element. This function is similar to
% meshresample, but it can both downsample or upsample a mesh
%
% author: Qianqian Fang (q.fang at neu.edu)
%
% input:
% node: list of nodes on the input suface mesh, 3 columns for x,y,z
% face: list of trianglular elements on the surface, [n1,n2,n3,region_id]
% opt: function parameters
% opt.gridsize: resolution for the voxelization of the mesh
% opt.closesize: if there are openings, set the closing diameter
% opt.elemsize: the size of the element of the output surface
% if opt is a scalar, it defines the elemsize and gridsize=opt/4
%
% output:
% newno: list of nodes on the resulting suface mesh, 3 columns for x,y,z
% newfc: list of trianglular elements on the surface, [n1,n2,n3,region_id]
%
% -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
%
p0=min(node);
p1=max(node);
if(isstruct(opt))
if(isfield(opt,'gridsize'))
dx=opt.gridsize;
end
else
dx=opt/4;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% step 1: convert the old surface to a volumetric image
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
img=surf2vol(node,face,p0(1)-dx:dx:p1(1)+dx,p0(2)-dx:dx:p1(2)+dx,p0(3)-dx:dx:p1(3)+dx);
eg=surfedge(face);
closesize=0;
if(~isempty(eg) && isstruct(opt))
if(isfield(opt,'closesize'))
closesize=opt.closesize;
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% step 2: fill holes in the volumetric binary image
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
img=fillholes3d(img,closesize);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% step 3: convert the filled volume to a new surface
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if(isstruct(opt))
if(isfield(opt,'elemsize'))
opt.radbound=opt.elemsize/dx;
[newno,newfc]=v2s(img,0.5,opt,'cgalsurf');
end
else
opt=struct('radbound',opt/dx);
[newno,newfc]=v2s(img,0.5,opt,'cgalsurf');
end
newno(:,1:3)=newno(:,1:3)*dx;
newno(:,1)=newno(:,1)+p0(1);
newno(:,2)=newno(:,2)+p0(2);
newno(:,3)=newno(:,3)+p0(3);
