JuliaSet with OCaml/GL

Inauguro la categoria per presentare il mio primo gist; si tratta di un semplice script per il rendering dell’insieme di Julia. Tempo fa’ avevo gia’ fatto qualcosa di simile, ho voluto reiterare l’esperienza con un linguaggio funzionale.

	(*
	Copyright (c) 2012, Davide Gessa (dakk)
	All rights reserved.
	Redistribution and use in source and binary forms, with or without modification, are permitted provided
	that the following conditions are met:
	– Redistributions of source code must retain the above copyright notice, this list of conditions and the
	following disclaimer.
	– Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
	the following disclaimer in the documentation and/or other materials provided with the distribution.
	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
	WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
	ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
	TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	POSSIBILITY OF SUCH DAMAGE.
	*)
	(* ocamlopt -I +lablGL lablgl.cmxa lablglut.cmxa julia_set.ml -o julia_set *)
	(* Calculate the julia set iteration in a generic point z *)
	let julia_calculate c (x,y) imax er =
	let z = {Complex.re=x; Complex.im=y} in
	let rec step i z =
	if Complex.norm(z) > er || i >= imax then i
	else step (i+1) (Complex.add (Complex.mul z z) c)
	in step 0 z
	;;
	let reshape ~w ~h =
	let w = max 1 w and h = max 1 h in
	GlDraw.viewport 0 0 w h;
	GlMat.mode `projection;
	GlMat.load_identity ();
	GlMat.ortho ~x:(–2., 2.) ~y:(–2., 2.) ~z:(0., 1.);
	GlMat.mode `modelview
	let display () =
	GlDraw.begins `points;
	for a = 0 to 640 – 1 do
	for b = 0 to 480 – 1 do
	let x = 3. *. float a /. float 640 -. 1.5 in
	let y = 3. *. float b /. float 480 -. 1.5 in
	let i = julia_calculate {Complex.re=(–0.70176); Complex.im=(–0.3842)} (x,y) 255 3.0 in
	let f i = 0.5 +. 0.5 *. cos(float i *. 0.1) in
	GlDraw.color (0.0, 0.0, f(i + 32));
	GlDraw.vertex ~x ~y ()
	done;
	done;
	GlDraw.ends ();
	Gl.flush ()
	let () =
	Glut.init Sys.argv;
	Glut.initWindowSize ~w: 640 ~h: 480;
	Glut.createWindow ~title: "Julia set";
	Glut.displayFunc ~cb: display;
	Glut.reshapeFunc ~cb:reshape;
	Glut.keyboardFunc ~cb: (fun ~key ~x ~y -> if key=27 then exit 0);
	Glut.mainLoop ()

view raw

julia_set.ml

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