rem                            D_PtLn.cdl
rem        Copy Right by International Technology Transfer Corp.
rem        revision 1.0 7/30/99   


rem        ********************************************************************
rem        Distance between Point and Line
rem        ********************************************************************

clear
defopt = 2

:start

	getpos "Indicate Point",defopt
	on (@key + 3) goto exit,start,start,
	defopt=@key
	x0 = @xworld
	y0 = @yworld
	z0 = @zworld
	
:line
	getent "Select Line",enttype
	on (@key + 3) goto exit, start, line, 
	if (enttype!=2)
		goto line
	x1 = @fltdat[0]
	y1 = @fltdat[1]
	z1 = @fltdat[2]
	x2 = @fltdat[3]
	y2 = @fltdat[4]
	z2 = @fltdat[5]
	
	f = x2 - x1
	g = y2 - y1
	h = z2 - z1


rem     Refer to L_PtLn.cdl
rem     ***********************************************************************
	t = (f * (x0 - x1) + g * (y0 - y1) + h * (z0 - z1)) / (f*f + g*g + h*h)

	x = x1 + f * t
	y = y1 + g * t
	z = z1 + h * t


	mode draw
	line x0, y0, z0, x, y, z, 15,,2
	mode normal

	dist=sqrt((x-x0)*(x-x0)+(y-y0)*(y-y0)+(z-z0)*(z-z0))
	pause " Distance between Point and Line = %.3f", dist

	redraw
	goto start
:exit