Update vtu_save.h

Author: TimGoTheCreator

src/io/vtu_save.h

@@ -2,42 +2,42 @@
 // it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
-
 // This program is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU General Public License for more details.
 
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
 #pragma once
 #include <vector>
 #include <string>
 #include <fstream>
-#include "../struct/particle.h"
+#include "struct/particle.h"
 
-inline void SaveVTU(const std::vector<Particle>& p, const std::string& filename)
+/**
+ * @brief Saves the SoA Particle database to a VTU (XML) file.
+ * This is the modern VTK format preferred by newer versions of ParaView.
+ */
+inline void SaveVTU(const Particle& p, const std::string& filename)
 {
     std::ofstream out(filename);
     if (!out) return;
 
-    const size_t N = p.size();
+    const size_t N = p.size(); // Total particles in the database
 
     out << "<?xml version=\"1.0\"?>\n";
     out << "<VTKFile type=\"UnstructuredGrid\" version=\"0.1\" byte_order=\"LittleEndian\">\n";
     out << "  <UnstructuredGrid>\n";
     out << "    <Piece NumberOfPoints=\"" << N 
         << "\" NumberOfCells=\"" << N << "\">\n";
 
-    // --- POINTS ---
+    // --- POINTS (Coordinates) ---
     out << "      <Points>\n";
     out << "        <DataArray type=\"Float32\" NumberOfComponents=\"3\" format=\"ascii\">\n          ";
-    for (const auto& a : p)
-        out << a.x << " " << a.y << " " << a.z << " ";
+    for (size_t i = 0; i < N; i++)
+        out << p.x[i] << " " << p.y[i] << " " << p.z[i] << " ";
     out << "\n        </DataArray>\n      </Points>\n";
 
-    // --- CELLS ---
+    // --- CELLS (Topology) ---
     out << "      <Cells>\n";
     out << "        <DataArray type=\"Int32\" Name=\"connectivity\" format=\"ascii\">\n          ";
     for (size_t i = 0; i < N; i++) out << i << " ";
@@ -51,25 +51,25 @@ inline void SaveVTU(const std::vector<Particle>& p, const std::string& filename)
     for (size_t i = 0; i < N; i++) out << "1 "; // 1 = VTK_VERTEX
     out << "\n        </DataArray>\n      </Cells>\n";
 
-    // --- POINT DATA ---
+    // --- POINT DATA (Attributes) ---
     out << "      <PointData>\n";
 
-    // Dark Matter Type (0 = Star, 1 = DM)
+    // Particle Type (0 = Star, 1 = DM)
     out << "        <DataArray type=\"Int32\" Name=\"type\" format=\"ascii\">\n          ";
-    for (const auto& a : p)
-        out << a.type << " ";
+    for (size_t i = 0; i < N; i++)
+        out << p.type[i] << " ";
     out << "\n        </DataArray>\n";
 
     // Velocity
     out << "        <DataArray type=\"Float32\" Name=\"velocity\" NumberOfComponents=\"3\" format=\"ascii\">\n          ";
-    for (const auto& a : p)
-        out << a.vx << " " << a.vy << " " << a.vz << " ";
+    for (size_t i = 0; i < N; i++)
+        out << p.vx[i] << " " << p.vy[i] << " " << p.vz[i] << " ";
     out << "\n        </DataArray>\n";
 
     // Mass
     out << "        <DataArray type=\"Float32\" Name=\"mass\" format=\"ascii\">\n          ";
-    for (const auto& a : p)
-        out << a.m << " ";
+    for (size_t i = 0; i < N; i++)
+        out << p.m[i] << " ";
     out << "\n        </DataArray>\n";
 
     out << "      </PointData>\n    </Piece>\n  </UnstructuredGrid>\n</VTKFile>\n";