From b1d61c67c28a9ba4a1de834e401d97cfc9e84764 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Sun, 21 Dec 2025 20:53:50 +0100
Subject: Reworking some structures. adding particle tests again

---
 util/vtk_renderer/kel_vtk_renderer.cpp | 80 ++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 util/vtk_renderer/kel_vtk_renderer.cpp

(limited to 'util/vtk_renderer/kel_vtk_renderer.cpp')

diff --git a/util/vtk_renderer/kel_vtk_renderer.cpp b/util/vtk_renderer/kel_vtk_renderer.cpp
new file mode 100644
index 0000000..516e4c3
--- /dev/null
+++ b/util/vtk_renderer/kel_vtk_renderer.cpp
@@ -0,0 +1,80 @@
+#include <vtkCamera.h>
+#include <vtkSmartPointer.h>
+#include <vtkStructuredPointsReader.h>  // Use vtkXMLStructuredGridReader for .vts
+#include <vtkStructuredPoints.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkDataSetSurfaceFilter.h>
+#include <vtkActor.h>
+#include <vtkRenderer.h>
+#include <vtkRenderWindow.h>
+#include <vtkWindowToImageFilter.h>
+#include <vtkPNGWriter.h>
+#include <sstream>
+#include <iomanip>
+
+int main()
+{
+    // Renderer & offscreen window
+    auto renderer = vtkSmartPointer<vtkRenderer>::New();
+    renderer->SetBackground(0.1, 0.2, 0.4);
+
+    auto renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
+    renderWindow->AddRenderer(renderer);
+    renderWindow->SetSize(800, 600);
+    renderWindow->OffScreenRenderingOn();  // No GUI
+
+    auto windowToImage = vtkSmartPointer<vtkWindowToImageFilter>::New();
+    windowToImage->SetInput(renderWindow);
+    windowToImage->SetInputBufferTypeToRGB();
+    windowToImage->ReadFrontBufferOff();
+
+    auto writer = vtkSmartPointer<vtkPNGWriter>::New();
+    writer->SetInputConnection(windowToImage->GetOutputPort());
+
+    // Camera setup (fixed)
+    renderer->GetActiveCamera()->SetPosition(0, 0, 10);
+    renderer->GetActiveCamera()->SetFocalPoint(0, 0, 0);
+    renderer->ResetCamera();
+
+    int startIndex = 0;
+    int endIndex = 1024; // adjust to your sequence length
+
+    for (int i = startIndex; i <= endIndex; ++i)
+    {
+        // Format input filename
+        std::ostringstream vtkFile;
+        vtkFile << "poiseulle_2d_gpu_" << (i*4) << ".vtk";
+
+        // Read structured points (equidistant grid)
+        auto reader = vtkSmartPointer<vtkStructuredPointsReader>::New();
+        reader->SetFileName(vtkFile.str().c_str());
+        reader->Update();
+
+        // Convert structured grid to surface for rendering
+        auto surfaceFilter = vtkSmartPointer<vtkDataSetSurfaceFilter>::New();
+        surfaceFilter->SetInputConnection(reader->GetOutputPort());
+        surfaceFilter->Update();
+
+        auto mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
+        mapper->SetInputConnection(surfaceFilter->GetOutputPort());
+
+        auto actor = vtkSmartPointer<vtkActor>::New();
+        actor->SetMapper(mapper);
+
+        // Clear previous frame
+        renderer->RemoveAllViewProps();
+        renderer->AddActor(actor);
+
+        // Render offscreen
+        renderWindow->Render();
+        windowToImage->Modified();
+
+        // Save PNG
+        std::ostringstream pngFile;
+        pngFile << "tmp/png/frame_" << std::setw(8) << std::setfill('0') << i << ".png";
+        writer->SetFileName(pngFile.str().c_str());
+        writer->Write();
+    }
+
+    return 0;
+}
-- 
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