Vector3f GetCameraPos( float scale , float *d = NULL , float * ss = NULL , Vector3f * p = NULL )
    {

        //if( scale < 0.0001f ) return P;
        //if( scale > 0.9999f ) return next -> P;

        double seek_distance = distance * scale;

        double dist = d ? *d : 0.0, old_dist , last_distance;
        double s = 0.05 , last = ss ? *ss : 0.0 , old_last ;

        Vector3f pos = p ? *p : P;

        Vector3f old_p;

        do
        {

            old_dist = dist;
            old_last = last;
            old_p    = pos;

            pos = SPline( P , P + T , next->P - next->T , next->P , 1.0 - ( last + s ) );

            last_distance = sqrt( ( pos - old_p ) . length_cubic() );

            if( dist + last_distance > seek_distance )
            {

                s *= 0.2;

                if( s < 0.00005 ) break;

            }
            else
            {
                last += s;
                dist += last_distance;
            }

        }
        while( 1 );


        if( ss ) *ss = old_last;
        if( p ) *p = old_p;
        if( d ) *d = old_dist;


        //s = ( seek_distance - old_dist ) / last_distance;
        //last = old_last + last_distance * s;

        //pos = SPline( P , P + T , next->P - next->T , next->P , clamp( 1.0 - last , 0.0, 1.0 ) );

        return pos;
    }