Gui: Move texture handling to view provider extension

It should be avoided to add all stuff to the base class when it's only needed in one sub-class

src/Gui/ViewProviderTextureExtension.h

@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+/***************************************************************************
+ *   Copyright (c) 2024 David Carter <dcarter@david.carter.ca>             *
+ *                                                                         *
+ *   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/>.                                      *
+ *                                                                         *
+ **************************************************************************/
+
+
+#ifndef GUI_VIEWPROVIDERTEXTUREEXT_H
+#define GUI_VIEWPROVIDERTEXTUREEXT_H
+
+#include <Gui/ViewProviderExtensionPython.h>
+
+class SoCoordinate3;
+class SoGroup;
+class SoIndexedFaceSet;
+class SoMaterial;
+class SoSwitch;
+class SoTexture2;
+class SoTexture3;
+
+namespace App
+{
+class Material;
+}
+
+namespace Gui
+{
+
+class GuiExport ViewProviderTextureExtension: public Gui::ViewProviderExtension
+{
+    EXTENSION_PROPERTY_HEADER_WITH_OVERRIDE(Gui::ViewProviderTextureExtension);
+
+public:
+    /// Constructor
+    ViewProviderTextureExtension();
+    ~ViewProviderTextureExtension() override;
+    void setup(SoMaterial*);
+    void setCoinAppearance(SoMaterial* pcShapeMaterial, const App::Material& source);
+    SoSwitch* getAppearance() const;
+    SoGroup* getTextureGroup3D() const;
+
+    /**
+     * Select which appearance type is active
+     *
+     */
+    /** Material only */
+    void activateMaterial();
+    /** 2D Texture */
+    void activateTexture2D();
+    /** 3D texture only */
+    void activateTexture3D();
+    /** Mix of material and 3D textures */
+    void activateMixed3D();
+
+private:
+    SoSwitch* pcSwitchAppearance {nullptr};
+    SoSwitch* pcSwitchTexture {nullptr};
+    SoTexture2* pcShapeTexture2D {nullptr};
+    SoGroup* pcTextureGroup3D {nullptr};
+};
+
+class GuiExport ViewProviderFaceTexture: public Gui::ViewProviderTextureExtension
+{
+    EXTENSION_PROPERTY_HEADER_WITH_OVERRIDE(Gui::ViewProviderFaceTexture);
+
+public:
+    /// Constructor
+    ViewProviderFaceTexture();
+    ~ViewProviderFaceTexture() override;
+    void setup(SoMaterial*);
+
+private:
+    // Used to support per face textures
+    SoTexture3        * pcShapeTexture3D;
+    SoCoordinate3     * pcShapeCoordinates;
+    SoIndexedFaceSet  * pcShapeFaceset;
+};
+
+} //namespace Gui
+
+
+#endif // GUI_VIEWPROVIDERTEXTUREEXT_H
+