#
# Examples of kernel approximation of freeform closed surface objects.
#
#					Gershon Elber, Oct 2002
#

OldCnvxPl2Vrtices = iritstate("CnvxPl2Vrtcs", 0);

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

c = cbspline( 4,
	      list( ctlpt( E2, 0,    0.15 ),
		    ctlpt( E2, 0.25, 0.15 ),
		    ctlpt( E2, 0.52, 0.4 ),
		    ctlpt( E2, 0.85, 0.3 ),
		    ctlpt( E2, 0.85, 0.0 ) ),
	      list( kv_open ) );
c = -c + c * sx( -1 );

srf8a = surfprev( c * ry( 90 ) ) * sx( 0.9 ) *
	             homomat( list( list( 1, 0, 0.2, 0 ),
				    list( 0, 1, 0, 0 ),
				    list( 0, 0, 1, 0 ),
				    list( 0, 0, 0, 1 ) ) ) *
	             homomat( list( list( 1, 0, 0, 0 ),
				    list( 0, 1, 0.2, 0 ),
				    list( 0, 0, 1, 0 ),
				    list( 0, 0, 0, 1 ) ) );

color( srf8a, yellow );
awidth( srf8a, 0.001 );

k = srfkernel( srf8a, 5, 3 );

view( list( srf8a, k ), 1 );
save( "srf1krnl", list( k, srf8a ) );

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

c = pcircle( vector( 0, 0, 0 ), 1 );
srf8b = -sFromCrvs( list( c * sc( 0.001 ),
		          c * sc( 1 ),
		          c * sc( 1 ) * tz( 1 ),
		          c * sc( 0.4 ) * sx( 0.6 ) * tz( 1 ),
		          c * sc( 0.4 ) * sx( 0.6 ) * tz( 2 ),
		          c * sc( 0.001 ) * tz( 2 ) ),
		    4, kv_open ) * sc( 0.3 );
color( srf8b, yellow );
awidth( srf8b, 0.001 );

k = srfkernel( srf8b, 40, 15 );

view( list( srf8b, k ), 1 );
save( "srf2krnl", list( k, srf8b ) );

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

c = pcircle( vector( 0, 0, 0 ), 1 );
srf8c = -sFromCrvs( list( c * sc( 0.001 ) * tz( -1 ),
		          c * sc( 0.4 ) * sy( 0.2 ) * tz( -1 ),
		          c * sc( 0.4 ) * sy( 0.2 ),
		          c * sc( 1 ),
		          c * sc( 1 ) * tz( 1 ),
		          c * sc( 0.4 ) * sx( 0.2 ) * tz( 1 ),
		          c * sc( 0.4 ) * sx( 0.2 ) * tz( 2 ),
		          c * sc( 0.001 ) * tz( 2 ) ),
		    4, kv_open ) * sc( 0.3 );
color( srf8c, yellow );
awidth( srf8c, 0.001 );

k = srfkernel( srf8c, 10, 12 );

view( list( srf8c, k ), 1 );
save( "srf3krnl", list( k, srf8c ) );

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

OldCnvxPl2Vrtices = iritstate("CnvxPl2Vrtcs", OldCnvxPl2Vrtices);
free( OldCnvxPl2Vrtices );

free( srf8a );
free( srf8b );
free( srf8c );
free( k );
free( c );