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(* interface.sml
*
* COPYRIGHT (c) 1992 AT&T Bell Laboratories
*
* The interface between the interpreter and the ray tracer.
*)
structure Interface =
struct
local
open Objects
in
(* color pops three numbers and pushes a color object.
* usage: red-value green-value blue-value color
*)
fun ps_color ((NUMBER blu)::(NUMBER grn)::(NUMBER red)::r) =
(COLOR(Color{red=red, grn=grn, blu=blu})) :: r
| ps_color stk = Interp.error "color" stk
(* pop radius, coordinates of center, and a color and push a sphere
* usage: radius x y z color-value sphere
*)
fun ps_sphere (
(COLOR c)::(NUMBER z)::(NUMBER y)::(NUMBER x)::(NUMBER rad)::r
) = SPHERE(Sphere{c=PT{x=x, y=y, z=z}, r=rad, color=c}) :: r
| ps_sphere stk = Interp.error "sphere" stk
(* build an object list from solids on the stack, then invoke raytracer *)
fun ps_raytrace ((LITERAL picName)::r) = let
fun mkObjList ([], l) = l
| mkObjList ((SPHERE s)::r, l) = mkObjList(r, s::l)
| mkObjList (_::r, l) = mkObjList(r, l)
in
Ray.picture(picName, mkObjList(r, []));
[]
end
| ps_raytrace stk = Interp.error "raytrace" stk
(* add ray tracing operations to interpreter dictionary *)
fun rtInit () = (
Interp.installOperator("color", ps_color);
Interp.installOperator("sphere", ps_sphere);
Interp.installOperator("raytrace", ps_raytrace))
end (* local *)
end;
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