/***************************************************************************
 *   Copyright (c) 2011 Werner Mayer <wmayer[at]users.sourceforge.net>     *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  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 Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/

#ifndef PARTGUI_SOBREPFACESET_H
#define PARTGUI_SOBREPFACESET_H

#include <Inventor/fields/SoSFInt32.h>
#include <Inventor/fields/SoMFInt32.h>
#include <Inventor/fields/SoSFNode.h>
#include <Inventor/fields/SoSubField.h>
#include <Inventor/nodes/SoSubNode.h>
#include <Inventor/nodes/SoIndexedFaceSet.h>
#include <Inventor/elements/SoLazyElement.h>
#include <Inventor/elements/SoReplacedElement.h>
#include <vector>

class SoGLCoordinateElement;
class SoTextureCoordinateBundle;

#if 0
#define RENDER_GLARRAYS
#endif

namespace PartGui {

/**
 * First some words to the history and the reason why we have this class:
 * In older FreeCAD versions we had an own Inventor node for each sub-element of a shape with its own highlight node.
 * For more complex objects the number of nodes increased dramatically with the result that interactions with such
 * objects was almost impossible because every little rotation or hovering caused a very time consuming redraw. The
 * most time consuming part was not the OpenGL calls to render the elements but the traversal of these many nodes.
 *
 * So, the idea was to have one node that handles all faces of a shape, one node that handles all edges and another node
 * that handles the vertexes. And each of these nodes manages the highlighting and selection itself.
 *
 * Now to SoBrepFaceSet in detail:
 * The most complex nodes of them is SoBrepFaceSet because it adds some extra logic for the handling of faces. As you can
 * see this class also has the attribute partIndex which is an array of integers. This basically expresses the logical
 * grouping of the faces in the coordIndex field -- the parts. This means that a part in SoBrepFaceSet corresponds to a face
 * in a shape object. Each part value gives you the number of triangles a certain face consists of. That's also the reason why
 * SoBrepFaceSet only renders triangles. If you want a quad to be rendered than create two triangles and set the corresponding
 * part number to 2.
 *
 * Example:
 * Let's say you have a shape with two faces. When meshing face 1 it creates 10 triangles and face 2 creates 5 triangles. Then
 * the partIndex attribute would be the array [10,5].
 * 
 * Highlighting/selection:
 * The highlightIndex now defines which part of the shape must be highlighted. So, in the above example it can have the values
 * 0, 1, or -1 (i.e. no highlighting). The highlightIndex is a SoSFInt32 field because only one part can be highlighted at a
 * moment while selectionIndex is a SoMFInt32 field because several parts can be selected at a time. All the logic how to do the
 * rendering is done inside renderHighlight()/renderSelection().
 *
 * Actually you can access the highlightIndex directly or you can apply a SoHighlightElementAction on it. And don't forget: if you
 * do some mouse picking and you got a SoFaceDetail then use getPartIndex() to get the correct part.
 *
 * As an example how to use the class correctly see ViewProviderPartExt::updateVisual().
 */
class PartGuiExport SoBrepFaceSet : public SoIndexedFaceSet {
    typedef SoIndexedFaceSet inherited;

    SO_NODE_HEADER(SoBrepFaceSet);

public:
    static void initClass();
    SoBrepFaceSet();

    SoMFInt32 partIndex;
    SoSFInt32 highlightIndex;
    SoMFInt32 selectionIndex;

protected:
    virtual ~SoBrepFaceSet();
    virtual void GLRender(SoGLRenderAction *action);
    virtual void GLRenderBelowPath(SoGLRenderAction * action);
    virtual void doAction(SoAction* action); 
    virtual SoDetail * createTriangleDetail(
        SoRayPickAction * action,
        const SoPrimitiveVertex * v1,
        const SoPrimitiveVertex * v2,
        const SoPrimitiveVertex * v3,
        SoPickedPoint * pp);
    virtual void generatePrimitives(SoAction * action);

private:
    enum Binding {
        OVERALL = 0,
        PER_PART,
        PER_PART_INDEXED,
        PER_FACE,
        PER_FACE_INDEXED,
        PER_VERTEX,
        PER_VERTEX_INDEXED,
        NONE = OVERALL
    };
    Binding findMaterialBinding(SoState * const state) const;
    Binding findNormalBinding(SoState * const state) const;
    void renderShape(const SoGLCoordinateElement * const vertexlist,
                     const int32_t *vertexindices,
                     int num_vertexindices,
                     const int32_t *partindices,
                     int num_partindices,
                     const SbVec3f *normals,
                     const int32_t *normindices,
                     SoMaterialBundle *const materials,
                     const int32_t *matindices,
                     SoTextureCoordinateBundle * const texcoords,
                     const int32_t *texindices,
                     const int nbind,
                     const int mbind,
                     const int texture);
    void renderHighlight(SoGLRenderAction *action);
    void renderSelection(SoGLRenderAction *action);

#ifdef RENDER_GLARRAYS
    void renderSimpleArray();
    void renderColoredArray(SoMaterialBundle *const materials);
#endif

private:
#ifdef RENDER_GLARRAYS
    std::vector<int32_t> index_array;
    std::vector<float> vertex_array;
#endif
    SbColor selectionColor;
    SbColor highlightColor;
    SoColorPacker colorpacker;
};

} // namespace PartGui

#endif // PARTGUI_SOBREPFACESET_H

