add s2.mli

src/s2/s2.mli

@@ -0,0 +1,37 @@
+module Gl : sig
+  exception Error of string * string
+end
+
+module Sdl : sig
+  exception Error of string
+end
+
+module Window : sig
+  type t
+  val make : title:string -> t
+  val destroy : t -> unit
+
+  val event_loop : t -> render:(float -> unit) -> unit
+end
+
+module Renderer : sig
+  open Adam
+
+  type t
+  val make : window:Window.t -> t
+  val destroy : t -> unit
+
+  val pre_draw : t -> unit
+  val post_draw : t -> unit
+  val clear : t -> color -> unit
+  val draw_rect : t -> tf:mat2a -> bb:aabb -> fill:color -> unit
+end
+
+module Asset : sig
+  open Sexplib
+
+  exception Error of string * string
+
+  val load_file : string -> string
+  val load_sexp_conv : string -> (Sexp.t -> 'a) -> 'a
+end