s2v.m

function varargout = s2v(node, face, div, varargin)
%
% [img,v2smap]=s2v(node,face,div)
%
% shortcut for surf2vol, coverting a surface to a volumetric image
%
% author: Qianqian Fang (q.fang at neu.edu)
%
% input:
%    node: node list of the triangular surface, 3 columns for x/y/z
%    face: triangle node indices, each row is a triangle
%    div:  division number along the shortest edge of the mesh (resolution)
%              if not given, div=50
%
% output:
%    img: a volumetric binary image at position of ndgrid(xi,yi,zi)
%        v2smap (optional): a 4x4 matrix denoting the Affine transformation to map
%             the voxel coordinates back to the mesh space. One can use the
%             v2smap to convert a mesh generated from the rasterized volume
%             into the original input mesh space (work coordinate system). For example:
%
%             [img,map]=s2v(node,face);
%             [no,el]=v2s(img,0.5,5);
%             newno=map*[no ones(length(no),1)]';
%             newno=newno(1:3,:)'; % newno and el now go back to the world coordinates
%
% -- this function is part of iso2mesh toolbox (http://iso2mesh.sf.net)
%

p0 = min(node);
p1 = max(node);

if (size(node, 1) == 0 || size(face, 1) == 0)
    error('node and face can not be empty');
end

if (nargin < 3)
    div = 50;
end

if (div == 0)
    error('div can not be 0');
end

dx = min(p1 - p0) / div;

if (dx <= eps)
    error('the input mesh is in a plane');
end

[varargout{1:2}] = surf2vol(node, face, p0(1) - dx:dx:p1(1) + dx, p0(2) - dx:dx:p1(2) + dx, p0(3) - dx:dx:p1(3) + dx, varargin{:});