Add HDF5 loading

Author: TimGoTheCreator

src/io/load_particle.hpp

@@ -16,18 +16,83 @@
 #include <fstream>
 #include <string>
 #include <vector>
+#include <stdexcept>
 
+// HDF5 C API
+#include <hdf5.h>
+
+// Helper: load one PartType group into particles
+void LoadPartType(hid_t file,
+                  const std::string& group,
+                  int internalType,
+                  std::vector<Particle>& particles)
+{
+    // Coordinates
+    if (H5Lexists(file, (group + "/Coordinates").c_str(), H5P_DEFAULT) <= 0)
+        return;
+
+    hid_t dset_coords = H5Dopen(file, (group + "/Coordinates").c_str(), H5P_DEFAULT);
+    hid_t space_coords = H5Dget_space(dset_coords);
+
+    hsize_t dims[2];
+    H5Sget_simple_extent_dims(space_coords, dims, NULL);
+    size_t N = dims[0]; // number of particles
+
+    std::vector<float> coords(N*3);
+    H5Dread(dset_coords, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, coords.data());
+
+    H5Dclose(dset_coords);
+    H5Sclose(space_coords);
+
+    // Velocities
+    hid_t dset_vels = H5Dopen(file, (group + "/Velocities").c_str(), H5P_DEFAULT);
+    std::vector<float> vels(N*3);
+    H5Dread(dset_vels, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, vels.data());
+    H5Dclose(dset_vels);
+
+    // Masses
+    hid_t dset_masses = H5Dopen(file, (group + "/Masses").c_str(), H5P_DEFAULT);
+    std::vector<float> masses(N);
+    H5Dread(dset_masses, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, masses.data());
+    H5Dclose(dset_masses);
+
+    // Convert into Particle structs
+    for (size_t i = 0; i < N; i++) {
+        Particle p;
+        p.x = coords[3*i+0];
+        p.y = coords[3*i+1];
+        p.z = coords[3*i+2];
+        p.vx = vels[3*i+0];
+        p.vy = vels[3*i+1];
+        p.vz = vels[3*i+2];
+        p.m = masses[i];
+        p.type = internalType;
+        particles.push_back(p);
+    }
+}
 
 std::vector<Particle> LoadParticlesFromFile(const std::string& filename)
 {
     std::vector<Particle> p;
-    std::ifstream in(filename);
 
+    // --- Try HDF5 first ---
+    hid_t file = H5Fopen(filename.c_str(), H5F_ACC_RDONLY, H5P_DEFAULT);
+    if (file >= 0) {
+        // Load PartType1 (DM → internal type=1)
+        LoadPartType(file, "PartType1", 1, p);
+
+        // Load PartType4 (Stars → internal type=0)
+        LoadPartType(file, "PartType4", 0, p);
+
+        H5Fclose(file);
+        return p;
+    }
+
+    // --- Fallback: plain text loader ---
+    std::ifstream in(filename);
     Particle temp;
-    // Match this to the file columns: x y z vx vy vz m type
     while (in >> temp.x >> temp.y >> temp.z >> temp.vx >> temp.vy >> temp.vz >> temp.m >> temp.type) {
         p.push_back(temp);
     }
-
     return p;
 }