used signed distance

mesh/sample_interior.m

@@ -1,13 +1,20 @@
-function C = sample_interior(V,F,n)
+function [C,D] = sample_interior(V,F,n,varargin)
   % SAMPLE_INTERIOR  Sample the interior of a solid bounded by the triangle
   % mesh (V,F)
   %
+  % C = sample_interior(V,F,n)
+  % C = sample_interior(V,F,n,...)
+  %
   % Inputs:
   %   V  #V by 3 list of mesh vertex positions
   %   F  #F by 3 list of triangle indices into V
   %   n  number of samples
+  %   Optional:
+  %     'MinDist' followed by minimum distance inside mesh, negative implies that
+  %       it's OK to be outside by that much.
   % Output:
   %   C  n by 3 list of samples
+  % 
   %
 
   % SAMPLE_BOUNDING_BOX  Smample the interour of the bounding box of V
@@ -22,10 +29,33 @@
     C = bsxfun(@plus, bsxfun(@times,rand(n,3),max(V)-min(V)),min(V));
   end
 
+  % default values
+  % Map of parameter names to variable names
+  min_dist = 0;
+  params_to_variables = containers.Map( ...
+    {'MinDist'}, ...
+    {'min_dist'});
+  v = 1;
+  while v <= numel(varargin)
+    param_name = varargin{v};
+    if isKey(params_to_variables,param_name)
+      assert(v+1<=numel(varargin));
+      v = v+1;
+      % Trick: use feval on anonymous function to use assignin to this workspace
+      feval(@()assignin('caller',params_to_variables(param_name),varargin{v}));
+    else
+      error('Unsupported parameter: %s',varargin{v});
+    end
+    v=v+1;
+  end
+
   out = 1:n;
   while ~isempty(out)
     C(out,:) = sample_bounding_box(V,numel(out));
-    w_out = winding_number(V,F,C(out,:));
-    out = out(abs(w_out)<0.5);
+    %w_out = winding_number(V,F,C(out,:));
+    %out = out(abs(w_out)<0.5);
+    % Negative is outside
+    D(out) = -signed_distance(C(out,:),V,F);
+    out = out(D(out)<min_dist);
   end
 end

mex/signed_distance.m

@@ -10,7 +10,7 @@
 %     'SignedDistanceType' followed by
 %       'winding_number' use winding number (continuous sign value for
 %         non-watertight)
-%       'pseudonormal'  use pseudo-normal, binary scale (but not robust for
+%       {'pseudonormal'}  use pseudo-normal, binary scale (but not robust for
 %         non-watertight meshes.
 % Outputs:
 %   S  #P list of smallest signed distances