Add read array from numpy file and write array to numpy file

.gitmodules

@@ -20,3 +20,6 @@
 [submodule "external/Noise"]
 	path = external/Noise
 	url = git@github.com:otto-link/Noise.git
+[submodule "external/libnpy"]
+	path = external/libnpy
+	url = git@github.com:llohse/libnpy.git

HighMap/CMakeLists.txt

@@ -31,6 +31,7 @@ target_link_libraries(
   FastNoiseLite::FastNoiseLite
   hmm::hmm
   libInterpolate::libInterpolate
+  libnpy::libnpy
   macro-logger::macro-logger
   NoiseLib
   OpenMP::OpenMP_CXX

HighMap/include/highmap/array.hpp

@@ -673,6 +673,16 @@ class Array
    */
   void from_file(std::string fname);
 
+  /**
+   * @brief Import array data from a numpy binary file.
+   *
+   * @param fname The name of the file to import data from.
+   *
+   * **Example**
+   * @include ex_from_numpy.cpp
+   */
+  void from_numpy(std::string fname);
+
   /**
    * @brief Display various information about the array.
    *
@@ -865,6 +875,16 @@ class Array
    */
   void to_file(std::string fname);
 
+  /**
+   * @brief Export the array to a numpy binary file.
+   *
+   * @param fname The name of the file to which the array data will be written.
+   *
+   * **Example**
+   * @include ex_to_numpy.cpp
+   */
+  void to_numpy(std::string fname);
+
   /**
    * @brief Export the array as a PNG image file with a specified colormap and
    * hillshading.

HighMap/src/array/array_io.cpp

@@ -4,6 +4,7 @@
 #include <fstream>
 
 #include "macrologger.h"
+#include "npy.hpp"
 
 #include "highmap/array.hpp"
 #include "highmap/io.hpp"
@@ -22,6 +23,35 @@ void Array::from_file(std::string fname)
   f.close();
 }
 
+void Array::from_numpy(std::string fname)
+{
+  npy::npy_data d = npy::read_npy<float>(fname);
+
+  // update array shape
+  Vec2<int> new_shape = {(int)d.shape[0], (int)d.shape[1]};
+  this->set_shape(new_shape);
+
+  // copy the data
+  if (d.fortran_order)
+  {
+    for (int i = 0; i < this->shape.x; i++)
+      for (int j = 0; j < this->shape.y; j++)
+      {
+        int k = j * this->shape.x + i;
+        (*this)(i, j) = d.data[k];
+      }
+  }
+  else
+  {
+    for (int i = 0; i < this->shape.x; i++)
+      for (int j = 0; j < this->shape.y; j++)
+      {
+        int k = i * this->shape.y + j;
+        (*this)(i, j) = d.data[k];
+      }
+  }
+}
+
 void Array::infos(std::string msg) const
 {
   std::cout << "Array: " << msg << " ";
@@ -58,6 +88,16 @@ void Array::to_file(std::string fname)
   f.close();
 }
 
+void Array::to_numpy(std::string fname)
+{
+  npy::npy_data_ptr<float> d;
+  d.data_ptr = this->vector.data();
+  d.shape = {(uint)this->shape.x, (uint)this->shape.y};
+  d.fortran_order = false;
+
+  npy::write_npy(fname, d);
+}
+
 void Array::to_png(std::string fname, int cmap, bool hillshading)
 {
   std::vector<uint8_t> img(3 * this->shape.x * this->shape.y);

examples/ex_from_numpy/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(ex_from_numpy ex_from_numpy.cpp)
+target_link_libraries(ex_from_numpy highmap)

examples/ex_from_numpy/ex_from_numpy.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+
+#include "highmap.hpp"
+
+int main(void)
+{
+  hmap::Vec2<int>   shape = {512, 256};
+  hmap::Vec2<float> res = {4.f, 2.f};
+  int               seed = 1;
+
+  hmap::Array z1 = hmap::noise_fbm(hmap::NoiseType::PERLIN, shape, res, seed);
+
+  z1.to_numpy("out.npy");
+
+  hmap::Array z2;
+  z2.from_numpy("out.npy");
+
+  hmap::export_banner_png("ex_from_numpy.png", {z1, z2}, hmap::cmap::inferno);
+}

examples/ex_to_numpy/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(ex_to_numpy ex_to_numpy.cpp)
+target_link_libraries(ex_to_numpy highmap)

examples/ex_to_numpy/ex_to_numpy.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+
+#include "highmap.hpp"
+
+int main(void)
+{
+  hmap::Vec2<int>   shape = {512, 256};
+  hmap::Vec2<float> res = {4.f, 2.f};
+  int               seed = 1;
+
+  hmap::Array z = hmap::noise_fbm(hmap::NoiseType::PERLIN, shape, res, seed);
+
+  std::cout << z(10, 12) << std::endl;
+
+  z.to_numpy("out.npy");
+  z.to_png("ex_to_numpy.png", hmap::cmap::jet);
+
+  // --- python script to check this
+
+  // import numpy as np
+  // z = np.load('out.npy')
+  // print(z.shape)
+  // print(z[10, 12])
+}

external/CMakeLists.txt

@@ -3,6 +3,7 @@ include(dkm.cmake)
 include(FastNoiseLite.cmake)
 include(hmm.cmake)
 include(libInterpolate.cmake)
+include(libnpy.cmake)
 include(macro-logger.cmake)
 include(xsimd.cmake)