From 0e8ac47fcf357d2159865baad855df65af9930d5 Mon Sep 17 00:00:00 2001
From: AndreaRigoni <andrea.rigoni@igi.cnr.it>
Date: Wed, 18 Mar 2026 07:23:58 +0000
Subject: [PATCH] grid axis

---
 .../testing/vtkDetectorChamberTest.cpp        | 27 ++++++-----
 src/Vtk/vtkViewport.cpp                       | 45 +++++++++++++------
 src/Vtk/vtkViewport.h                         |  5 +++
 3 files changed, 52 insertions(+), 25 deletions(-)

diff --git a/src/Vtk/HEP/Detectors/testing/vtkDetectorChamberTest.cpp b/src/Vtk/HEP/Detectors/testing/vtkDetectorChamberTest.cpp
index 0573cc5..3afd306 100644
--- a/src/Vtk/HEP/Detectors/testing/vtkDetectorChamberTest.cpp
+++ b/src/Vtk/HEP/Detectors/testing/vtkDetectorChamberTest.cpp
@@ -31,28 +31,31 @@
 #define BOOST_TEST_MODULE vtkDetectorChamberTest
 #include <boost/test/unit_test.hpp>
 
+using namespace uLib;
+
 BOOST_AUTO_TEST_CASE(vtkDetectorChamberTest) {
-  uLib::DetectorChamber d1, d2;
-  d1.SetSize(uLib::Vector3f(1, 1, 1));
-  d1.SetPosition(uLib::Vector3f(0, 0, 0));
-  d1.Scale(uLib::Vector3f(5, 10, 2));
-  d1.Translate(uLib::Vector3f(0, 0, 0));
+  DetectorChamber d1, d2;
+  d1.SetSize(Vector3f(1, 1, 1));
+  d1.SetPosition(Vector3f(0, 0, 0));
+  d1.Scale(Vector3f(5, 10, 2));
+  d1.Translate(Vector3f(0, 0, 0));
 
-  d2.SetSize(uLib::Vector3f(1, 1, 1));
-  d2.SetPosition(uLib::Vector3f(0, 0, 0));
-  d2.Scale(uLib::Vector3f(5, 10, 2));
-  d2.Translate(uLib::Vector3f(0, 0, 10));
+  d2.SetSize(Vector3f(1, 1, 1));
+  d2.SetPosition(Vector3f(0, 0, 0));
+  d2.Scale(Vector3f(5, 10, 2));
+  d2.Translate(Vector3f(0, 0, 10));
 
 
-  uLib::Vtk::vtkDetectorChamber vtkDetectorChamber(&d1);
-  uLib::Vtk::vtkDetectorChamber vtkDetectorChamber2(&d2);
+  Vtk::vtkDetectorChamber vtkDetectorChamber(&d1);
+  Vtk::vtkDetectorChamber vtkDetectorChamber2(&d2);
 
   if (!vtkDetectorChamber.GetProp()) {
     BOOST_FAIL("vtkDetectorChamber::GetProp() returned NULL");
   }
 
   if (std::getenv("CTEST_PROJECT_NAME") == nullptr) {
-    uLib::Vtk::Viewer viewer;
+    Vtk::Viewer viewer;
+    viewer.SetGridAxis(Vtk::Viewport::Y);
     viewer.AddPuppet(vtkDetectorChamber);
     viewer.AddPuppet(vtkDetectorChamber2);
     viewer.Start();
diff --git a/src/Vtk/vtkViewport.cpp b/src/Vtk/vtkViewport.cpp
index ab3fed9..cf3e59e 100644
--- a/src/Vtk/vtkViewport.cpp
+++ b/src/Vtk/vtkViewport.cpp
@@ -29,6 +29,7 @@ Viewport::Viewport()
     , m_Marker(vtkSmartPointer<vtkOrientationMarkerWidget>::New())
     , m_CameraWidget(nullptr)
     , m_Colors(vtkSmartPointer<vtkNamedColors>::New())
+    , m_GridAxis(Y)
 {
 }
 
@@ -267,6 +268,13 @@ bool Viewport::GetGridVisible() const
     return false;
 }
 
+void Viewport::SetGridAxis(Axis axis)
+{
+    m_GridAxis = axis;
+    UpdateGrid();
+    Render();
+}
+
 void Viewport::addProp(vtkProp* prop)
 {
     if (m_Renderer) {
@@ -313,24 +321,35 @@ void Viewport::UpdateGrid()
     double focalPoint[3];
     camera->GetFocalPoint(focalPoint);
 
-    // Align center to spacing
-    double centerX = std::round(focalPoint[0] / spacing) * spacing;
-    double centerY = std::round(focalPoint[1] / spacing) * spacing;
+    // Indices for the two dimensions of the grid plane
+    int idxH, idxV, idxN;
+    if (m_GridAxis == X) { idxH = 1; idxV = 2; idxN = 0; }
+    else if (m_GridAxis == Y) { idxH = 0; idxV = 2; idxN = 1; }
+    else { idxH = 0; idxV = 1; idxN = 2; }
 
-    // Number of lines: enough to cover the screen even if aspect ratio is wide
-    // or if we rotate. 20x20 is usually plenty.
+    // Align center to spacing
+    double centerH = std::round(focalPoint[idxH] / spacing) * spacing;
+    double centerV = std::round(focalPoint[idxV] / spacing) * spacing;
+    double centerN = 0.0; // Grid plane typically passes through the origin
+
+    // Number of lines
     int numLines = 20;
     double halfSize = (numLines / 2.0) * spacing;
 
-    double xmin = centerX - halfSize;
-    double xmax = centerX + halfSize;
-    double ymin = centerY - halfSize;
-    double ymax = centerY + halfSize;
+    double minH = centerH - halfSize;
+    double maxH = centerH + halfSize;
+    double minV = centerV - halfSize;
+    double maxV = centerV + halfSize;
 
-    // Update Plane Source
-    m_GridSource->SetOrigin(xmin, ymin, 0.0);
-    m_GridSource->SetPoint1(xmax, ymin, 0.0);
-    m_GridSource->SetPoint2(xmin, ymax, 0.0);
+    // Update Plane Source mapping axes to origin/point1/point2
+    double origin[3] = {0,0,0}, p1[3] = {0,0,0}, p2[3] = {0,0,0};
+    origin[idxH] = minH; origin[idxV] = minV; origin[idxN] = centerN;
+    p1[idxH]     = maxH; p1[idxV]     = minV; p1[idxN]     = centerN;
+    p2[idxH]     = minH; p2[idxV]     = maxV; p2[idxN]     = centerN;
+
+    m_GridSource->SetOrigin(origin);
+    m_GridSource->SetPoint1(p1);
+    m_GridSource->SetPoint2(p2);
     m_GridSource->SetXResolution(numLines);
     m_GridSource->SetYResolution(numLines);
     m_GridSource->Update();
diff --git a/src/Vtk/vtkViewport.h b/src/Vtk/vtkViewport.h
index 6ae8085..4f2e11a 100644
--- a/src/Vtk/vtkViewport.h
+++ b/src/Vtk/vtkViewport.h
@@ -65,6 +65,10 @@ public:
     void SetGridVisible(bool visible);
     bool GetGridVisible() const;
 
+    enum Axis { X=0, Y, Z };
+    void SetGridAxis(Axis axis);
+    Axis GetGridAxis() const { return m_GridAxis; }
+
 protected:
     void SetupPipeline(vtkRenderWindowInteractor* iren);
 
@@ -82,6 +86,7 @@ protected:
 
     vtkSmartPointer<vtkNamedColors>              m_Colors;
     
+    Axis                                         m_GridAxis;
     vtkSmartPointer<vtkHandlerWidget>            m_HandlerWidget;
     std::vector<Puppet*>                         m_Puppets;
     vtkSmartPointer<vtkCellPicker>               m_Picker;