/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * 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
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSG_TERMPLATEPRIMITIVEINDEXFUNCTOR
#define OSG_TERMPLATEPRIMITIVEINDEXFUNCTOR 1

#include <osg/PrimitiveSet>
#include <osg/Notify>

namespace osg {


/** Provides access to the primitives that compose an \c osg::Drawable.
    *  <p>Notice that \c TemplatePrimitiveIndexFunctor is a class template, and that it inherits
    *  from its template parameter \c T. This template parameter must implement
    *  <tt>operator()(const osg::Vec3 v1, const osg::Vec3 v2, const osg::Vec3
    *  v3, bool treatVertexDataAsTemporary)</tt>,
    *  <tt>operator()(const osg::Vec3 v1, const osg::Vec3 v2, bool
    *  treatVertexDataAsTemporary)</tt>, <tt>operator()(const osg::Vec3 v1,
    *  const osg::Vec3 v2, const osg::Vec3 v3, bool treatVertexDataAsTemporary)</tt>,
    *  and <tt>operator()(const osg::Vec3 v1, const osg::Vec3 v2, const osg::Vec3 v3,
    *  const osg::Vec3 v4, bool treatVertexDataAsTemporary)</tt> which will be called
    *  for the matching primitive when the functor is applied to a \c Drawable.
    *  Parameters \c v1, \c v2, \c v3, and \c v4 are the vertices of the primitive.
    *  The last parameter, \c treatVertexDataAsTemporary, indicates whether these
    *  vertices are coming from a "real" vertex array, or from a temporary vertex array,
    *  created by the \c TemplatePrimitiveIndexFunctor from some other geometry representation.
    *  @see \c PrimitiveFunctor for general usage hints.
    */
template<class T>
class TemplatePrimitiveIndexFunctor : public PrimitiveIndexFunctor, public T
{
public:

    TemplatePrimitiveIndexFunctor() {}

    virtual ~TemplatePrimitiveIndexFunctor() {}

    virtual void setVertexArray(unsigned int,const Vec2*) {}
    virtual void setVertexArray(unsigned int ,const Vec3*) {}
    virtual void setVertexArray(unsigned int,const Vec4*) {}
    virtual void setVertexArray(unsigned int,const Vec2d*) {}
    virtual void setVertexArray(unsigned int ,const Vec3d*) {}
    virtual void setVertexArray(unsigned int,const Vec4d*) {}

    virtual void drawArrays(GLenum mode,GLint first,GLsizei count)
    {
        switch(mode)
        {
            case(GL_TRIANGLES):
            {
                unsigned int pos=first;
                for(GLsizei i=2;i<count;i+=3,pos+=3)
                {
                    this->operator()(pos,pos+1,pos+2);
                }
                break;
            }
            case(GL_TRIANGLE_STRIP):
             {
                unsigned int pos=first;
                for(GLsizei i=2;i<count;++i,++pos)
                {
                    if ((i%2)) this->operator()(pos,pos+2,pos+1);
                    else       this->operator()(pos,pos+1,pos+2);
                }
                break;
            }
            case(GL_QUADS):
            {
                unsigned int pos=first;
                for(GLsizei i=3;i<count;i+=4,pos+=4)
                {
                    this->operator()(pos,pos+1,pos+2,pos+3);
                }
                break;
            }
            case(GL_QUAD_STRIP):
            {
                unsigned int pos=first;
                for(GLsizei i=3;i<count;i+=2,pos+=2)
                {
                    this->operator()(pos,pos+1,pos+2,pos+3);
                }
                break;
            }
            case(GL_POLYGON): // treat polygons as GL_TRIANGLE_FAN
            case(GL_TRIANGLE_FAN):
            {
                unsigned int pos=first+1;
                for(GLsizei i=2;i<count;++i,++pos)
                {
                    this->operator()(first,pos,pos+1);
                }
                break;
            }
            case(GL_POINTS):
            {
                unsigned int pos=first;
                for(GLsizei i=0;i<count;++i,++pos)
                {
                    this->operator()(pos);
                }
                break;
            }
            case(GL_LINES):
            {
                unsigned int pos=first;
                for(GLsizei i=1;i<count;i+=2,pos+=2)
                {
                    this->operator()(pos,pos+1);
                }
                break;
            }
            case(GL_LINE_STRIP):
            {
                unsigned int pos=first;
                for(GLsizei i=1;i<count;++i,++pos)
                {
                    this->operator()(pos,pos+1);
                }
                break;
            }
            case(GL_LINE_LOOP):
            {
                unsigned int pos=first;
                for(GLsizei i=1;i<count;++i,++pos)
                {
                    this->operator()(pos,pos+1);
                }
                this->operator()(first+count-1,first);
                break;
            }
            default:
                // can't be converted into to triangles.
                break;
        }
    }

    virtual void drawElements(GLenum mode,GLsizei count,const GLubyte* indices)
    {
        if (indices==0 || count==0) return;

        typedef GLubyte Index;
        typedef const Index* IndexPointer;

        switch(mode)
        {
            case(GL_TRIANGLES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=3)
                    this->operator()(*iptr,*(iptr+1),*(iptr+2));
                break;
            }
            case(GL_TRIANGLE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    if ((i%2)) this->operator()(*(iptr),*(iptr+2),*(iptr+1));
                    else       this->operator()(*(iptr),*(iptr+1),*(iptr+2));
                }
                break;
            }
            case(GL_QUADS):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=4,iptr+=4)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_QUAD_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=2,iptr+=2)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_POLYGON): // treat polygons as GL_TRIANGLE_FAN
            case(GL_TRIANGLE_FAN):
            {
                IndexPointer iptr = indices;
                Index first = *iptr;
                ++iptr;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    this->operator()(first,*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_POINTS):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;++iptr)
                    this->operator()(*iptr);
                break;
            }
            case(GL_LINES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=2)
                    this->operator()(*iptr,*(iptr+1));
                break;
            }
            case(GL_LINE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_LINE_LOOP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                this->operator()(*(iptr),*(indices));
                break;
            }
            default:
                // can't be converted into to triangles.
                break;
        }
    }


    virtual void drawElements(GLenum mode,GLsizei count,const GLushort* indices)
    {
        if (indices==0 || count==0) return;

        typedef GLushort Index;
        typedef const Index* IndexPointer;

        switch(mode)
        {
            case(GL_TRIANGLES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=3)
                    this->operator()(*iptr,*(iptr+1),*(iptr+2));
                break;
            }
            case(GL_TRIANGLE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    if ((i%2)) this->operator()(*(iptr),*(iptr+2),*(iptr+1));
                    else       this->operator()(*(iptr),*(iptr+1),*(iptr+2));
                }
                break;
            }
            case(GL_QUADS):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=4,iptr+=4)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_QUAD_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=2,iptr+=2)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_POLYGON): // treat polygons as GL_TRIANGLE_FAN
            case(GL_TRIANGLE_FAN):
            {
                IndexPointer iptr = indices;
                Index first = *iptr;
                ++iptr;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    this->operator()(first,*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_POINTS):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;++iptr)
                    this->operator()(*iptr);
                break;
            }
            case(GL_LINES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=2)
                    this->operator()(*iptr,*(iptr+1));
                break;
            }
            case(GL_LINE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_LINE_LOOP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                this->operator()(*(iptr),*(indices));
                break;
            }
            default:
                // can't be converted into to triangles.
                break;
        }
    }

    virtual void drawElements(GLenum mode,GLsizei count,const GLuint* indices)
    {
        if (indices==0 || count==0) return;

        typedef GLuint Index;
        typedef const Index* IndexPointer;

        switch(mode)
        {
            case(GL_TRIANGLES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=3)
                    this->operator()(*iptr,*(iptr+1),*(iptr+2));
                break;
            }
            case(GL_TRIANGLE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    if ((i%2)) this->operator()(*(iptr),*(iptr+2),*(iptr+1));
                    else       this->operator()(*(iptr),*(iptr+1),*(iptr+2));
                }
                break;
            }
            case(GL_QUADS):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=4,iptr+=4)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_QUAD_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=3;i<count;i+=2,iptr+=2)
                {
                    this->operator()(*(iptr),*(iptr+1),*(iptr+2),*(iptr+3));
                }
                break;
            }
            case(GL_POLYGON): // treat polygons as GL_TRIANGLE_FAN
            case(GL_TRIANGLE_FAN):
            {
                IndexPointer iptr = indices;
                Index first = *iptr;
                ++iptr;
                for(GLsizei i=2;i<count;++i,++iptr)
                {
                    this->operator()(first,*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_POINTS):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;++iptr)
                    this->operator()(*iptr);
                break;
            }
            case(GL_LINES):
            {
                IndexPointer ilast = &indices[count];
                for(IndexPointer iptr=indices;iptr<ilast;iptr+=2)
                    this->operator()(*iptr,*(iptr+1));
                break;
            }
            case(GL_LINE_STRIP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                break;
            }
            case(GL_LINE_LOOP):
            {
                IndexPointer iptr = indices;
                for(GLsizei i=1;i<count;++i,++iptr)
                {
                    this->operator()(*(iptr),*(iptr+1));
                }
                this->operator()(*(iptr),*(indices));
                break;
            }
            default:
                // can't be converted into to triangles.
                break;
        }
    }

};


}

#endif
