#
# Simple knots.
#
#						Gershon Elber, 1997
#
Cross = pcircle( vector( 0, 0, 0 ), 0.1 );

Crv1 = coerce( cbspline( 3,
		         list( ctlpt( E3, -1, 0.9, 0 ),
		               ctlpt( E3, 1, 0.9, 0 ),
		               ctlpt( E3, 1, -0.9, 0 ),
		               ctlpt( E3, -1, -0.9, 0 ) ),
		         list( KV_PERIODIC ) ),
	       KV_OPEN );
Srf1 = swpsclsrf( Cross, Crv1, 1.0, vector( 0, 0, 1 ), 2 );
attrib( Srf1, "color", red );

Crv2 = coerce( cbspline( 3,
		         list( ctlpt( E3, -1.3, 0, 0.75 ),
		               ctlpt( E3, 1.3, 0, 0.75 ),
		               ctlpt( E3, 1.3, 0, -0.75 ),
		               ctlpt( E3, -1.3, 0, -0.75 ) ),
		         list( KV_PERIODIC ) ),
	       KV_OPEN );
Srf2 = swpsclsrf( Cross, Crv2, 1.0, vector( 0, 1, 0 ), 2 );
attrib( Srf2, "color", green );

Crv3 = coerce( cbspline( 3,
		         list( ctlpt( E3, 0, 0.5, 1.1 ),
			       ctlpt( E3, 0, 0.5, -1.1 ),
		               ctlpt( E3, 0, -0.5, -1.1 ),
		               ctlpt( E3, 0, -0.5, 1.1 ) ),
		         list( KV_PERIODIC ) ),
	       KV_OPEN );
Srf3 = swpsclsrf( Cross, Crv3, 1.0, vector( 1, 0, 0 ), 2 );
attrib( Srf3, "color", cyan );

Knots = list( Srf1, Srf2, Srf3 );
attrib( Knots, "u_resolution", 0.1 );

interact( Knots );
save( "knots", Knots );

free( Cross );
free( Crv1 );
free( Crv2 );
free( Crv3 );
free( Srf1 );
free( Srf2 );
free( Srf3 );
free( Knots );