#
# Computing crv(s) tangencies.
#

DisplayPtsCrcTan2Crvs = function( Pts, R, c1, c2 ):
    i: Pt: Prms: PtC1: PtC2: Circ:
    return  = nil():
    Circ = circle( vector( 0, 0, 0 ), R ):
    for ( i = 1, 1, sizeof( Pts ),
        Pt = coord( Pts, i ):
        Prms = getAttr( Pt, "Params" ):
        PtC1 = ceval( c1, coord( Prms, 0 ) ):
        PtC2 = ceval( c2, coord( Prms, 1 ) ):
        snoc( list( coerce( Pt, E2 ) + PtC1,
		    coerce( Pt, E2 ) + PtC2,
	            Circ * trans( coerce( Pt, vector_type ) ) ),
	      return ) );

view_mat1 = tx( 0 );
viewobj( view_mat1 );

#############################################################################

c1 = ctlpt( e2, 0, 2 ) + ctlpt( e2, 0, -2 );
color( c1, green );

c2 = cbspline( 3,
    list( ctlpt( E3, -0.0448, 0.808, 0 ),
          ctlpt( E2, -0.193, 0.201 ),
          ctlpt( E2, -0.867, 0.179 ),
          ctlpt( E2, -0.151, -0.309 ),
          ctlpt( E2, -0.517, -0.666 ),
          ctlpt( E2, 0.00856, -0.84 ),
          ctlpt( E2, 0.327, -0.704 ),
          ctlpt( E2, 0.147, -0.109 ),
          ctlpt( E2, 0.33, -0.0551 ),
          ctlpt( E2, 0.486, 0.142 ),
          ctlpt( E2, 0.393, 0.623 ) ),
    list( kv_periodic ) );
c2 = coerce( c2, kv_open );
color( c2, yellow );

R = 0.1;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

save( "crv1tan", list( c1, c2, PtsDsp ) );

R = 0.2;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

R = 0.4;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

R = 1.0;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

#############################################################################

c1 = cbspline( 4,
    list( ctlpt( E3, -0.132, 0.302, 0 ),
          ctlpt( E2, -0.704, 0.843 ),
          ctlpt( E2, -0.433, 1.03 ),
          ctlpt( E2, -0.101, 1.07 ),
          ctlpt( E2, -0.758, 1.2 ),
          ctlpt( E2, -0.794, -1.01 ),
          ctlpt( E2, -1.18, 1.06 ),
          ctlpt( E2, -1.11, -0.00834 ),
          ctlpt( E2, -1.05, -0.405 ),
          ctlpt( E2, -0.681, -0.619 ),
          ctlpt( E2, -0.12, -0.163 ),
          ctlpt( E2, 0.476, -0.374 ),
          ctlpt( E2, 0.738, -0.282 ),
          ctlpt( E2, 0.961, 0.0287 ),
          ctlpt( E2, 0.965, 0.407 ),
          ctlpt( E2, 0.202, 0.298 ) ),
    list( kv_periodic ) );
c1 = coerce( c1, kv_open );
color( c1, green );

c2 = cbspline( 3,
    list( ctlpt( E3, -0.0448, 0.808, 0 ),
          ctlpt( E2, -0.193, 0.201 ),
          ctlpt( E2, -0.867, 0.179 ),
          ctlpt( E2, -0.151, -0.309 ),
          ctlpt( E2, -0.517, -0.666 ),
          ctlpt( E2, 0.00856, -0.84 ),
          ctlpt( E2, 0.327, -0.704 ),
          ctlpt( E2, 0.147, -0.109 ),
          ctlpt( E2, 0.33, -0.0551 ),
          ctlpt( E2, 0.486, 0.142 ),
          ctlpt( E2, 0.393, 0.623 ) ),
    list( kv_periodic ) );
c2 = coerce( c2, kv_open );
color( c2, yellow );

R = 0.1;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

save( "crv2tan", list( c1, c2, PtsDsp ) );

R = 0.2;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

R = 0.4;
Pts = Crc2CrvTan( c1, c2, R, 1e-3 );
PtsDsp = DisplayPtsCrcTan2Crvs( Pts, R, c1, c2 );

interact( list( c1, c2, PtsDsp ) );

#############################################################################

free( R );
free( c1 );
free( c2 );
free( Pts );
free( PtsDsp );
free( view_mat1 );