Core: Implement SoFCTransform node

In its doAction() method it only sets the model matrix if it's not the identity matrix.
This improves the issue #7606

src/Gui/Inventor/SoFCTransform.cpp

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+/***************************************************************************
+ *   Copyright (c) 2024 Werner Mayer <wmayer[at]users.sourceforge.net>     *
+ *                                                                         *
+ *   This file is part of FreeCAD.                                         *
+ *                                                                         *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
+ *                                                                         *
+ *   FreeCAD 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      *
+ *   Lesser General Public License for more details.                       *
+ *                                                                         *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
+ *                                                                         *
+ **************************************************************************/
+
+#include "PreCompiled.h"
+
+#ifndef _PreComp_
+#include <Inventor/actions/SoCallbackAction.h>
+#include <Inventor/actions/SoGetBoundingBoxAction.h>
+#include <Inventor/actions/SoGetPrimitiveCountAction.h>
+#include <Inventor/actions/SoGLRenderAction.h>
+#include <Inventor/actions/SoPickAction.h>
+#include <Inventor/elements/SoModelMatrixElement.h>
+#endif
+
+#include "SoFCTransform.h"
+
+
+using namespace Gui;
+
+SO_NODE_SOURCE(SoFCTransform)
+
+void SoFCTransform::initClass()
+{
+    SO_NODE_INIT_CLASS(SoFCTransform, SoTransform, "Transform");
+}
+
+SoFCTransform::SoFCTransform()
+{
+    SO_NODE_CONSTRUCTOR(SoFCTransform);
+}
+
+void SoFCTransform::GLRender(SoGLRenderAction * action)
+{
+    SoFCTransform::doAction(action);
+}
+
+void SoFCTransform::callback(SoCallbackAction * action)
+{
+    SoFCTransform::doAction(action);
+}
+
+void SoFCTransform::pick(SoPickAction * action)
+{
+    SoFCTransform::doAction(action);
+}
+
+void SoFCTransform::getPrimitiveCount(SoGetPrimitiveCountAction * action)
+{
+    SoFCTransform::doAction(action);
+}
+
+void SoFCTransform::getBoundingBox(SoGetBoundingBoxAction * action)
+{
+    SoFCTransform::doAction(action);
+}
+
+void SoFCTransform::doAction(SoAction * action)
+{
+    SbMatrix matrix;
+    matrix.setTransform(this->translation.getValue(),
+                        this->rotation.getValue(),
+                        this->scaleFactor.getValue(),
+                        this->scaleOrientation.getValue(),
+                        this->center.getValue());
+
+    // This is different to SoTransform::doAction() where model matrix
+    // is always set
+    if (matrix != SbMatrix::identity()) {
+        SoModelMatrixElement::mult(action->getState(), this, matrix);
+    }
+}