/*
 * ODE::Mass::Box#initialize( density, sideX, sideY, sideZ[, totalmass] )
 * --
 * Create and return a box Mass of the given dimensions and density, with the
 * center of mass at (0,0,0) relative to the body. If the optional
 * <tt>totalmass</tt> parameter is given, adjust the values so the total mass is
 * <tt>totalmass</tt> before returning.
 */
static VALUE
ode_mass_box_init( argc, argv, self )
	 int	argc;
	 VALUE	*argv, self;
{
	ode_MASS	*ptr;
	VALUE		density, lx, ly, lz, totalmass;

	rb_scan_args( argc, argv, "41", &density, &lx, &ly, &lz, &totalmass );

	CheckPositiveNonZeroNumber( NUM2DBL(density), "density" );
	CheckPositiveNonZeroNumber( NUM2DBL(lx), "sideX" );
	CheckPositiveNonZeroNumber( NUM2DBL(ly), "sideY" );
	CheckPositiveNonZeroNumber( NUM2DBL(lz), "sideZ" );

	rb_call_super( 0, 0 );
	ptr = get_mass( self );

	dMassSetBox( ptr->massptr,
				 NUM2DBL(density),
				 NUM2DBL(lx),
				 NUM2DBL(ly),
				 NUM2DBL(lz) );

	/* If a totalmass argument was given, check and set it */
	if ( RTEST(totalmass) ) {
		CheckPositiveNonZeroNumber( NUM2DBL(totalmass), "totalmass" );
		dMassAdjust( ptr->massptr, (dReal)NUM2DBL(totalmass) );
	}

	return self;
}