---

TriangleStrip.cpp

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/*
    TEDDY - General graphics application library
    Copyright (C) 1999-2002  Timo Suoranta
    tksuoran@cc.helsinki.fi

    This library 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.

    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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    $Id:  $
*/


#include "Teddy/Models/TriangleStrip.h"
#include "Teddy/Models/Vertex.h"
#include "Teddy/PhysicalComponents/Projection.h"
#include "Teddy/SysSupport/Messages.h"
#include "Teddy/SysSupport/StdIO.h"
using namespace Teddy::SysSupport;


namespace Teddy  {
namespace Models {


TriangleStrip::TriangleStrip(){
}


/*virtual*/ TriangleStrip::~TriangleStrip(){
    //  FIX
}


/*virtual*/ void TriangleStrip::draw( Projection *p ){

    if( isEnabled(EL_USE_ELEMENT_NORMAL|EL_HAS_ELEMENT_NORMAL) ){
        dmsg( M_INIT, "Drawing flat trianglestrip" );

        p->beginTriangles();

        list<Vector*>::const_iterator n_it  = normals .begin();
        list<Vertex*>::const_iterator v1_it = vertices.begin();
        list<Vertex*>::const_iterator v2_it = v1_it;
        bool swap = true;
        while( n_it != normals.end() && v2_it != vertices.end() ){
            Vector *normal = *n_it++;
            p->normal( *normal );
            v2_it = v1_it;
            Vertex *a = *v2_it++; if( v2_it == vertices.end() ){ dmsg( M_WARN, "TriangleStrip missing vertices" ); break; }
            Vertex *b = *v2_it++; if( v2_it == vertices.end() ){ dmsg( M_WARN, "TriangleStrip missing vertices" ); break; }
            Vertex *c = *v2_it++;
            if( swap ){
                b->draw( p );
                a->draw( p );
            }else{
                a->draw( p );
                b->draw( p );
            }
            c->draw( p );
            dprint( M_INIT, "." );
            v1_it++;
            swap = !swap;
        }

        p->end();

    }else{
        dmsg( M_INIT, "Drawing smoothed trianglestrip" );

        p->beginTriangleStrip();
        list<Vertex*>::const_iterator v_it = vertices.begin();
        while( v_it != vertices.end() ){
            (*v_it)->draw( p );
            v_it++;
        }

        p->end();
    }

}



/*virtual*/ void TriangleStrip::makeNormal(){
    list<Vertex*>::iterator v_i1 = vertices.begin();
    list<Vertex*>::iterator v_i2 = v_i1;

    if( vertices.size()<3 ){
        dmsg( M_WARN,
            "Element does not have enough vertices for normal calculation (%d vertices found)",
            vertices.size()
        );
        normal = Vector(0,1,0);
        return;
    }

    normals.clear();
    float len;
    bool swap = true;
    Vector a;
    Vector b;
    Vector c;
    do{
        v_i2 = v_i1++;

        if( swap ){
            if( v_i2 == vertices.end() ){ dmsg( M_WARN, "TriangleStripe normal problem" ); return; }
            b  = (*v_i2++)->getVertex();
            if( v_i2 == vertices.end() ){ dmsg( M_WARN, "TriangleStripe normal problem" ); return; }
            a  = (*v_i2++)->getVertex();
        }else{
            if( v_i2 == vertices.end() ){ dmsg( M_WARN, "TriangleStripe normal problem" ); return; }
            a  = (*v_i2++)->getVertex();
            if( v_i2 == vertices.end() ){ dmsg( M_WARN, "TriangleStripe normal problem" ); return; }
            b  = (*v_i2++)->getVertex();
        }

        if( v_i2 == vertices.end() ){ dmsg( M_WARN, "TriangleStripe normal problem" ); return; }
        c  = (*v_i2++)->getVertex();

        Vector ab = b-a;
        ab.normalize();
        Vector bc = c-b;
        bc.normalize();
        float test = ab | bc;
        normal = (a-c)^(a-b);
        normal.normalize();
        len = normal.magnitude();
        if( len < 0.9 || len >11.1 ){
            dmsg( M_WARN, "TriangleStripe normal problem" );
            return;
        }
        if( test == -1.0 || test == 1.0 ){
        }else{
            this->normal = normal;
        }
        normals.push_back( new Vector(normal) );
        swap = !swap;
    }while( v_i2 != vertices.end() );

    enable( EL_HAS_ELEMENT_NORMAL | EL_USE_ELEMENT_NORMAL );
}



#if defined( TEDDY_INCLUDE_COLDET )
/*virtual*/ int TriangleStrip::addToCollisionModel( Teddy::ColDet::CollisionModel3D *collision_model ){
    int tris = 0;
    list<Vertex*>::const_iterator v_it  = vertices.begin();

    FloatVector a  = (*v_it)->getVertex(); v_it++; if( v_it == vertices.end() ) return 0;
    FloatVector b  = (*v_it)->getVertex(); v_it++;
    while( v_it != vertices.end() ){
        FloatVector c = (*v_it)->getVertex();
        collision_model->addTriangle( a, b, c );
        a  = b;
        b  = c;
        tris++;
        v_it++;
    }
    return tris;
}
#endif


//  CSG
/*virtual*/ unsigned long TriangleStrip::countCSGFaceElements(){
    unsigned long size = vertices.size();
    return size - 2;
}


};  //  namespace Models
};  //  namespace Teddy