Minor API update for Cartesian_grid_3

Isosurfacing_3/benchmark/Isosurfacing_3/benchmark.cpp

@@ -171,7 +171,7 @@ struct Grid_sphere
   Grid_sphere(const std::size_t N)
   {
     const CGAL::Bbox_3 bbox{-1., -1., -1., 1., 1., 1.};
-    grid = Grid { bbox, N, N, N };
+    grid = Grid { bbox, CGAL::make_array<std::size_t>(N, N, N) };
 
     values = { grid };
     gradients = { grid };

Isosurfacing_3/benchmark/Isosurfacing_3/contouring_seq_vs_parallel_implicit.cpp

@@ -46,7 +46,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox = {-2., -2., -2., 2., 2., 2.};
-  Grid grid { bbox, 150, 150, 150 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(150, 150, 150) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/contouring_discrete_data.cpp

@@ -108,7 +108,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox { -1., -1., -1., 1., 1., 1. };
-  Grid grid { bbox, 30, 30, 30 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(30, 30, 30) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/contouring_image.cpp

@@ -96,7 +96,7 @@ int main(int argc, char* argv[])
 
   // convert image to a Cartesian grid
   Grid grid;
-  Values values { grid };
+  Values values { grid }; // 'values' keeps a reference to the grid
   if(!IS::IO::read_Image_3(image, grid, values))
   {
     std::cerr << "Error: Cannot convert image to Cartesian grid" << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/contouring_mesh_offset.cpp

@@ -156,8 +156,10 @@ int main(int argc, char** argv)
   bbox += (Point(bbox.xmax(), bbox.ymax(), bbox.zmax()) + aabb_increase_vec).bbox();
   bbox += (Point(bbox.xmin(), bbox.ymin(), bbox.zmin()) - aabb_increase_vec).bbox();
 
-  const int n_voxels = 250;
+  const int nv = 15;
-  Grid grid { bbox, n_voxels, n_voxels, n_voxels };
+
+  bbox = CGAL::Bbox_3{ -5, -5, -5, 15, 15, 15 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(nv, nv, nv) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/dual_contouring.cpp

@@ -29,7 +29,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox { -1., -1., -1., 1., 1., 1. };
-  Grid grid { bbox, 30, 30, 30 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(30, 30, 30) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/dual_contouring_intersection_oracles.cpp

@@ -47,7 +47,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox = {-2., -2., -2., 2., 2., 2.};
-  Grid grid { bbox, 50, 50, 50 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(50, 50, 50) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/dual_contouring_strategies.cpp

@@ -45,7 +45,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox = {-2., -2., -2., 2., 2., 2.};
-  Grid grid { bbox, 50, 50, 50 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(50, 50, 50) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/marching_cubes.cpp

@@ -27,7 +27,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox { -1., -1., -1., 1., 1., 1. };
-  Grid grid { bbox, 30, 30, 30 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(30, 30, 30) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/examples/Isosurfacing_3/marching_cubes_strategies.cpp

@@ -28,7 +28,7 @@ int main(int argc, char** argv)
 
   // create bounding box and grid
   const CGAL::Bbox_3 bbox { -1., -1., -1., 1., 1., 1. };
-  Grid grid { bbox, 30, 30, 30 };
+  Grid grid { bbox, CGAL::make_array<std::size_t>(30, 30, 30) };
 
   std::cout << "Bbox: " << grid.bbox() << std::endl;
   std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;

Isosurfacing_3/include/CGAL/Isosurfacing_3/Cartesian_grid_3.h

@@ -85,7 +85,7 @@ public:
 private:
   Iso_cuboid_3 m_bbox;
   std::array<std::size_t, 3> m_sizes;
-  std::array<FT, 3> m_spacing;
+  Vector_3 m_spacing;
 
   Geom_traits m_gt;
 
@@ -95,6 +95,7 @@ private:
     auto x_coord = m_gt.compute_x_3_object();
     auto y_coord = m_gt.compute_y_3_object();
     auto z_coord = m_gt.compute_z_3_object();
+    auto vector = m_gt.construct_vector_3_object();
     auto vertex = m_gt.construct_vertex_3_object();
 
     // calculate grid spacing
@@ -108,7 +109,7 @@ private:
     const FT d_y = y_span / (m_sizes[1] - 1);
     const FT d_z = z_span / (m_sizes[2] - 1);
 
-    m_spacing = make_array(d_x, d_y, d_z);
+    m_spacing = vector(d_x, d_y, d_z);
   }
 
 public:
@@ -128,20 +129,16 @@ public:
    * The grid covers the space described by a bounding box.
    *
    * \param bbox the bounding box of the grid
-   * \param xdim the number of grid vertices in the `x` direction
+   * \param dimensions the number of grid vertices in the `x`, `y`, and `z` directions
-   * \param ydim the number of grid vertices in the `y` direction
-   * \param zdim the number of grid vertices in the `z` direction
    * \param gt the geometric traits
    *
-   * \pre `xdim`, `ydim`, and `zdim` are (strictly) positive.
+   * \pre all dimensions are (strictly) positive.
    */
   Cartesian_grid_3(const Iso_cuboid_3& bbox,
-                   const std::size_t xdim,
+                   const std::array<std::size_t, 3>& dimensions,
-                   const std::size_t ydim,
-                   const std::size_t zdim,
                    const Geom_traits& gt = Geom_traits())
     : m_bbox{bbox},
-      m_sizes{xdim, ydim, zdim},
+      m_sizes{dimensions},
       m_gt{gt}
   {
     compute_spacing();
@@ -154,20 +151,16 @@ public:
    *
    * \param p the lowest corner of the bounding box of the grid
    * \param q the upper corner of the bounding box of the grid
-   * \param xdim the number of grid vertices in the `x` direction
+   * \param dimensions the number of grid vertices in the `x`, `y`, and `z` directions
-   * \param ydim the number of grid vertices in the `y` direction
-   * \param zdim the number of grid vertices in the `z` direction
    * \param gt the geometric traits
    *
    * \pre `p` is lexicographically (strictly) smaller than `q`
-   * \pre `xdim`, `ydim`, and `zdim` are (strictly) positive.
+   * \pre all dimensions are (strictly) positive.
    */
   Cartesian_grid_3(const Point_3& p, const Point_3& q,
-                   const std::size_t xdim,
+                   const std::array<std::size_t, 3>& dimensions,
-                   const std::size_t ydim,
-                   const std::size_t zdim,
                    const Geom_traits& gt = Geom_traits())
-    : Cartesian_grid_3{Iso_cuboid_3{p, q}, xdim, ydim, zdim, gt}
+    : Cartesian_grid_3{Iso_cuboid_3{p, q}, dimensions, gt}
   { }
 
   /**
@@ -182,7 +175,7 @@ public:
    * \pre the diagonal of `bbox` has length a multiple of `spacing`
    */
   Cartesian_grid_3(const Iso_cuboid_3& bbox,
-                   const std::array<FT, 3>& spacing,
+                   const Vector_3& spacing,
                    const Geom_traits& gt = Geom_traits())
     : m_bbox{bbox},
       m_spacing{spacing},
@@ -218,7 +211,7 @@ public:
    * \pre the diagonal of the bounding box has length a multiple of `spacing`
    */
   Cartesian_grid_3(const Point_3& p, const Point_3& q,
-                   const std::array<FT, 3>& spacing,
+                   const Vector_3& spacing,
                    const Geom_traits& gt = Geom_traits())
     : Cartesian_grid_3{Iso_cuboid_3{p, q}, spacing, gt}
   { }
@@ -250,7 +243,7 @@ public:
    * returns the spacing of the %Cartesian grid, that is a vector whose coordinates are
    * the grid steps in the `x`, `y`, and `z` directions, respectively
    */
-  const std::array<FT, 3>& spacing() const { return m_spacing; }
+  const Vector_3& spacing() const { return m_spacing; }
 
   /**
    * returns the number of grid vertices in the `x` direction
@@ -273,7 +266,7 @@ public:
    */
   void set_sizes(const std::size_t xdim, const std::size_t ydim, const std::size_t zdim)
   {
-    m_sizes = {xdim, ydim, zdim};
+    m_sizes = { xdim, ydim, zdim };
     compute_spacing();
   }
 
@@ -309,7 +302,6 @@ public:
     std::size_t j = (y_coord(p) - y_coord(min_p)) / m_spacing[1];
     std::size_t k = (z_coord(p) - z_coord(min_p)) / m_spacing[2];
 
-    // @todo check this
     if(i == xdim() - 1)
       --i;
     if(j == ydim() - 1)

Isosurfacing_3/include/CGAL/Isosurfacing_3/interpolation_schemes_3.h

@@ -62,15 +62,14 @@ public:
 
     // trilinear interpolation of stored values
     const Iso_cuboid_3& bbox = g.bbox();
-    const std::array<FT, 3>& spacing = g.spacing();
+    const Vector_3& spacing = g.spacing();
 
     // calculate min index including border case
     const Point_3& min_p = vertex(bbox, 0);
-    std::size_t i = (x_coord(p) - x_coord(min_p)) / spacing[0];
+    std::size_t i = (x_coord(p) - x_coord(min_p)) / x_coord(spacing);
-    std::size_t j = (y_coord(p) - y_coord(min_p)) / spacing[1];
+    std::size_t j = (y_coord(p) - y_coord(min_p)) / y_coord(spacing);
-    std::size_t k = (z_coord(p) - z_coord(min_p)) / spacing[2];
+    std::size_t k = (z_coord(p) - z_coord(min_p)) / z_coord(spacing);
 
-    // @todo check this
     if(i == g.xdim() - 1)
       --i;
     if(j == g.ydim() - 1)
@@ -134,13 +133,13 @@ public:
 
     // trilinear interpolation of stored gradients
     const Iso_cuboid_3& bbox = g.bbox();
-    const std::array<FT, 3>& spacing = g.spacing();
+    const Vector_3& spacing = g.spacing();
 
     // calculate min index including border case
     const Point_3& min_p = vertex(bbox, 0);
-    std::size_t i = static_cast<std::size_t>((x_coord(p) - x_coord(min_p)) / spacing[0]);
+    std::size_t i = static_cast<std::size_t>((x_coord(p) - x_coord(min_p)) / x_coord(spacing));
-    std::size_t j = static_cast<std::size_t>((y_coord(p) - y_coord(min_p)) / spacing[1]);
+    std::size_t j = static_cast<std::size_t>((y_coord(p) - y_coord(min_p)) / y_coord(spacing));
-    std::size_t k = static_cast<std::size_t>((z_coord(p) - z_coord(min_p)) / spacing[2]);
+    std::size_t k = static_cast<std::size_t>((z_coord(p) - z_coord(min_p)) / z_coord(spacing));
 
     if(i == g.xdim() - 1) // dim is the point number
       --i;

Isosurfacing_3/test/Isosurfacing_3/test_marching_cubes.cpp

@@ -60,7 +60,7 @@ void test_grid_sphere(const std::size_t n)
 
   Sphere_function sphere_function;
 
-  Grid grid{n, n, n, bbox};
+  Grid grid { bbox, CGAL::make_array<std::size_t>(n, n, n) };
 
   for(std::size_t x=0; x<grid.xdim(); ++x) {
     for(std::size_t y=0; y<grid.ydim(); ++y) {