marching cubes consolidate and tutorial entry

Former-commit-id: 4bbd0306810aad9b1bd2da5304507d4ceb9e674f

tutorial/705_MarchingCubes/CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 2.6)
+project(705_MarchingCubes)
+
+include("../CMakeLists.shared")
+
+set(SOURCES
+${PROJECT_SOURCE_DIR}/main.cpp
+)
+
+add_executable(${PROJECT_NAME}_bin ${SOURCES} ${SHARED_SOURCES})
+target_link_libraries(${PROJECT_NAME}_bin ${SHARED_LIBRARIES})

tutorial/705_MarchingCubes/main.cpp

@@ -0,0 +1,90 @@
+#include <igl/marching_cubes.h>
+#include <igl/signed_distance.h>
+#include <igl/read_triangle_mesh.h>
+#include <igl/viewer/Viewer.h>
+#include <Eigen/Core>
+#include <iostream>
+
+int main(int argc, char * argv[])
+{
+  using namespace Eigen;
+  using namespace std;
+  using namespace igl;
+  MatrixXi F;
+  MatrixXd V;
+  // Read in inputs as double precision floating point meshes
+  read_triangle_mesh(
+      "../shared/armadillo.obj",V,F);
+  // number of vertices on the largest side
+  const int s = 50;
+  const RowVector3d Vmin = V.colwise().minCoeff();
+  const RowVector3d Vmax = V.colwise().maxCoeff();
+  const double h = (Vmax-Vmin).maxCoeff()/(double)s;
+  const RowVector3i res = (s*((Vmax-Vmin)/(Vmax-Vmin).maxCoeff())).cast<int>();
+  // create grid
+  cout<<"Creating grid..."<<endl;
+  MatrixXd GV(res(0)*res(1)*res(2),3);
+  for(int zi = 0;zi<res(2);zi++)
+  {
+    const auto lerp = [&](const int di, const int d)->double
+      {return Vmin(d)+(double)di/(double)(res(d)-1)*(Vmax(d)-Vmin(d));};
+    const double z = lerp(zi,2);
+    for(int yi = 0;yi<res(1);yi++)
+    {
+      const double y = lerp(yi,1);
+      for(int xi = 0;xi<res(0);xi++)
+      {
+        const double x = lerp(xi,0);
+        GV.row(xi+res(0)*(yi + res(1)*zi)) = RowVector3d(x,y,z);
+      }
+    }
+  }
+  // compute values
+  cout<<"Computing distances..."<<endl;
+  VectorXd S,B;
+  {
+    VectorXi I;
+    MatrixXd C,N;
+    signed_distance(GV,V,F,SIGNED_DISTANCE_TYPE_PSEUDONORMAL,S,I,C,N);
+    // Convert distances to binary inside-outside data --> aliasing artifacts
+    B = S;
+    for_each(B.data(),B.data()+B.size(),[](double& b){b=(b>0?1:(b<0?-1:0));});
+  }
+  cout<<"Marching cubes..."<<endl;
+  MatrixXd SV,BV;
+  MatrixXi SF,BF;
+  marching_cubes(S,GV,res(0),res(1),res(2),SV,SF);
+  marching_cubes(B,GV,res(0),res(1),res(2),BV,BF);
+
+  cout<<R"(Usage:
+'1'  Show original mesh.
+'2'  Show marching cubes contour of signed distance.
+'3'  Show marching cubes contour of indicator function.
+)";
+  igl::viewer::Viewer viewer;
+  viewer.data.set_mesh(SV,SF);
+  viewer.callback_key_down = 
+    [&](igl::viewer::Viewer & viewer, unsigned char key, int mod)->bool
+    {
+      switch(key)
+      {
+        default:
+          return false;
+        case '1':
+          viewer.data.clear();
+          viewer.data.set_mesh(V,F);
+          break;
+        case '2':
+          viewer.data.clear();
+          viewer.data.set_mesh(SV,SF);
+          break;
+        case '3':
+          viewer.data.clear();
+          viewer.data.set_mesh(BV,BF);
+          break;
+      }
+      viewer.data.set_face_based(true);
+      return true;
+    };
+  viewer.launch();
+}

tutorial/CMakeLists.txt

@@ -148,3 +148,4 @@ add_subdirectory("701_Statistics")
 add_subdirectory("702_WindingNumber")
 add_subdirectory("703_Decimation")
 add_subdirectory("704_SignedDistance")
+add_subdirectory("705_MarchingCubes")

tutorial/images/armadillo-marching-cubes.jpg.REMOVED.git-id

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tutorial/tutorial.html.REMOVED.git-id

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tutorial/tutorial.md.REMOVED.git-id

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