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#include <CGAL/Simple_cartesian.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/draw_surface_mesh.h>
#include <CGAL/Graphics_scene_options.h>
#include <iostream>
typedef CGAL::Simple_cartesian<double> Kernel;
typedef Kernel::Point_3 Point;
typedef CGAL::Surface_mesh<Point> Mesh;
struct Colored_faces_given_height:
public CGAL::Graphics_scene_options<Mesh,
typename Mesh::Vertex_index,
typename Mesh::Edge_index,
typename Mesh::Face_index>
{
Colored_faces_given_height(const Mesh& sm)
{
if(sm.is_empty()) return;
double m_min_y=0., m_max_y=0.;
bool first=true;
for(typename Mesh::Vertex_index vi: sm.vertices())
{
if(first)
{ m_min_y=sm.point(vi).y(); m_max_y=m_min_y; first=false; }
else
{
m_min_y=(std::min)(m_min_y, sm.point(vi).y());
m_max_y=(std::max)(m_max_y, sm.point(vi).y());
}
}
this->colored_face=[](const Mesh &, typename Mesh::Face_index)->bool { return true; };
this->face_color=[m_min_y, m_max_y]
(const Mesh& sm, typename Mesh::Face_index fi)->CGAL::IO::Color
{
double res=0.;
std::size_t n=0;
for(typename Mesh::Vertex_index vi: vertices_around_face(sm.halfedge(fi), sm))
{
res+=sm.point(vi).y();
++n;
}
// Random color depending on the "height" of the facet
CGAL::Random random(static_cast<unsigned int>(30*((res/n)-m_min_y)/(m_max_y-m_min_y)));
return CGAL::get_random_color(random);
};
}
};
int main(int argc, char* argv[])
{
const std::string filename = (argc>1) ? argv[1] : CGAL::data_file_path("meshes/elephant.off");
Mesh sm;
if(!CGAL::IO::read_polygon_mesh(filename, sm))
{
std::cerr << "Invalid input file: " << filename << std::endl;
return EXIT_FAILURE;
}
CGAL::draw(sm, Colored_faces_given_height(sm));
return EXIT_SUCCESS;
}
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