58 lines
1.5 KiB
C++
Executable File
58 lines
1.5 KiB
C++
Executable File
#include <igl/avg_edge_length.h>
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#include <igl/barycenter.h>
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#include <igl/grad.h>
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#include <igl/jet.h>
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#include <igl/readDMAT.h>
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#include <igl/readOFF.h>
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#include <igl/opengl/glfw/Viewer.h>
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#include <iostream>
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#include "tutorial_shared_path.h"
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int main(int argc, char *argv[])
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{
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using namespace Eigen;
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using namespace std;
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MatrixXd V;
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MatrixXi F;
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// Load a mesh in OFF format
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igl::readOFF(TUTORIAL_SHARED_PATH "/cheburashka.off", V, F);
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// Read scalar function values from a file, U: #V by 1
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VectorXd U;
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igl::readDMAT(TUTORIAL_SHARED_PATH "/cheburashka-scalar.dmat",U);
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// Compute gradient operator: #F*3 by #V
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SparseMatrix<double> G;
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igl::grad(V,F,G);
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// Compute gradient of U
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MatrixXd GU = Map<const MatrixXd>((G*U).eval().data(),F.rows(),3);
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// Compute gradient magnitude
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const VectorXd GU_mag = GU.rowwise().norm();
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igl::opengl::glfw::Viewer viewer;
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viewer.data.set_mesh(V, F);
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// Compute pseudocolor for original function
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MatrixXd C;
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igl::jet(U,true,C);
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// // Or for gradient magnitude
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//igl::jet(GU_mag,true,C);
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viewer.data.set_colors(C);
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// Average edge length divided by average gradient (for scaling)
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const double max_size = igl::avg_edge_length(V,F) / GU_mag.mean();
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// Draw a black segment in direction of gradient at face barycenters
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MatrixXd BC;
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igl::barycenter(V,F,BC);
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const RowVector3d black(0,0,0);
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viewer.data.add_edges(BC,BC+max_size*GU, black);
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// Hide wireframe
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viewer.core.show_lines = false;
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viewer.launch();
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}
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