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 () |
