From b6527a709882ae72bbb959f2d08e9c751dfbd96a Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sun, 12 Dec 2021 12:49:53 +0100
Subject: [PATCH] Gui: add function View3DInventorViewer::projectPointToLine
 and expose to Python

---
 src/Gui/View3DInventorViewer.cpp | 21 +++++++++++++++++++--
 src/Gui/View3DInventorViewer.h   |  4 ++++
 src/Gui/View3DPy.cpp             | 29 +++++++++++++++++++++++++++++
 src/Gui/View3DPy.h               |  1 +
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/src/Gui/View3DInventorViewer.cpp b/src/Gui/View3DInventorViewer.cpp
index b6e65286f3..4e692e41a3 100644
--- a/src/Gui/View3DInventorViewer.cpp
+++ b/src/Gui/View3DInventorViewer.cpp
@@ -2597,7 +2597,7 @@ SbRotation View3DInventorViewer::getCameraOrientation() const
     return cam->orientation.getValue();
 }
 
-SbVec3f View3DInventorViewer::getPointOnFocalPlane(const SbVec2s& pnt) const
+SbVec2f View3DInventorViewer::getNormalizedPosition(const SbVec2s& pnt) const
 {
     const SbViewportRegion& vp = this->getSoRenderManager()->getViewportRegion();
 
@@ -2620,6 +2620,12 @@ SbVec3f View3DInventorViewer::getPointOnFocalPlane(const SbVec2s& pnt) const
         pY = (pY - 0.5f*dY) / fRatio + 0.5f*dY;
     }
 
+    return SbVec2f(pX, pY);
+}
+
+SbVec3f View3DInventorViewer::getPointOnFocalPlane(const SbVec2s& pnt) const
+{
+    SbVec2f pnt2d = getNormalizedPosition(pnt);
     SoCamera* pCam = this->getSoRenderManager()->getCamera();
 
     if (!pCam) return SbVec3f();  // return invalid point
@@ -2636,7 +2642,7 @@ SbVec3f View3DInventorViewer::getPointOnFocalPlane(const SbVec2s& pnt) const
     SbLine line;
     SbVec3f pt;
     SbPlane focalPlane = vol.getPlane(focalDist);
-    vol.projectPointToLine(SbVec2f(pX,pY), line);
+    vol.projectPointToLine(pnt2d, line);
     focalPlane.intersect(line, pt);
 
     return pt;
@@ -2718,6 +2724,17 @@ SbVec3f View3DInventorViewer::projectOnFarPlane(const SbVec2f& pt) const
     return pt2;
 }
 
+void View3DInventorViewer::projectPointToLine(const SbVec2s& pt, SbVec3f& pt1, SbVec3f& pt2) const
+{
+    SbVec2f pnt2d = getNormalizedPosition(pt);
+    SoCamera* pCam = this->getSoRenderManager()->getCamera();
+
+    if (!pCam) return;
+
+    SbViewVolume vol = pCam->getViewVolume();
+    vol.projectPointToLine(pnt2d, pt1, pt2);
+}
+
 void View3DInventorViewer::toggleClippingPlane(int toggle, bool beforeEditing,
         bool noManip, const Base::Placement &pla)
 {
diff --git a/src/Gui/View3DInventorViewer.h b/src/Gui/View3DInventorViewer.h
index 71fb7c17d6..6006df0e25 100644
--- a/src/Gui/View3DInventorViewer.h
+++ b/src/Gui/View3DInventorViewer.h
@@ -311,6 +311,10 @@ public:
     SbVec3f projectOnNearPlane(const SbVec2f&) const;
     /** Project the given normalized 2d point onto the far plane */
     SbVec3f projectOnFarPlane(const SbVec2f&) const;
+    /** Project the given 2d point to a line */
+    void projectPointToLine(const SbVec2s&, SbVec3f& pt1, SbVec3f& pt2) const;
+    /** Get the normalized position of the 2d point. */
+    SbVec2f getNormalizedPosition(const SbVec2s&) const;
     //@}
 
     /** @name Dimension controls
diff --git a/src/Gui/View3DPy.cpp b/src/Gui/View3DPy.cpp
index 2cbd9d2714..75f294ede9 100644
--- a/src/Gui/View3DPy.cpp
+++ b/src/Gui/View3DPy.cpp
@@ -166,6 +166,10 @@ void View3DInventorPy::init_type()
         "getPointOnScreen(3D vector) -> pixel coords (as integer)\n"
         "\n"
         "Return the projected 3D point (in pixel coordinates).\n");
+    add_varargs_method("projectPointToLine",&View3DInventorPy::projectPointToLine,
+        "projectPointToLine(pixel coords (as integer)) -> line defined by two points\n"
+        "\n"
+        "Return the projecting 3D line to the given 2D point");
     add_varargs_method("addEventCallback",&View3DInventorPy::addEventCallback,"addEventCallback()");
     add_varargs_method("removeEventCallback",&View3DInventorPy::removeEventCallback,"removeEventCallback()");
     add_varargs_method("setAnnotation",&View3DInventorPy::setAnnotation,"setAnnotation()");
@@ -1710,6 +1714,31 @@ Py::Object View3DInventorPy::getPointOnScreen(const Py::Tuple& args)
     }
 }
 
+Py::Object View3DInventorPy::projectPointToLine(const Py::Tuple& args)
+{
+    short x,y;
+    if (!PyArg_ParseTuple(args.ptr(), "hh", &x, &y)) {
+        PyErr_Clear();
+        Py::Tuple t(args[0]);
+        x = (int)Py::Int(t[0]);
+        y = (int)Py::Int(t[1]);
+    }
+    try {
+        SbVec3f pt1, pt2;
+        getView3DIventorPtr()->getViewer()->projectPointToLine(SbVec2s(x,y), pt1, pt2);
+        Py::Tuple tuple(2);
+        tuple.setItem(0, Py::Vector(Base::Vector3f(pt1[0], pt1[1], pt1[2])));
+        tuple.setItem(1, Py::Vector(Base::Vector3f(pt2[0], pt2[1], pt2[2])));
+        return tuple;
+    }
+    catch (const Base::Exception& e) {
+        throw Py::RuntimeError(e.what());
+    }
+    catch (const Py::Exception&) {
+        throw;
+    }
+}
+
 Py::Object View3DInventorPy::listNavigationTypes(const Py::Tuple&)
 {
     std::vector<Base::Type> types;
diff --git a/src/Gui/View3DPy.h b/src/Gui/View3DPy.h
index 2ca76f6813..52f96a10ff 100644
--- a/src/Gui/View3DPy.h
+++ b/src/Gui/View3DPy.h
@@ -115,6 +115,7 @@ public:
     Py::Object getObjectsInfo(const Py::Tuple&);
     Py::Object getSize(const Py::Tuple&);
     Py::Object getPointOnFocalPlane(const Py::Tuple&);
+    Py::Object projectPointToLine(const Py::Tuple&);
     Py::Object getPointOnScreen(const Py::Tuple&);
     Py::Object addEventCallback(const Py::Tuple&);
     Py::Object removeEventCallback(const Py::Tuple&);