ocaml+sdl+opengl ?

ocaml+sdl+opengl ?

[Florent Monnier]

Hi,
I'm trying to use ocamlsdl for the windowing of an OpenGL application.

You will find below 2 test files, one using LablGL and one using glMLite.

I have made these test:

sdl+glMLite in interpreted mode => OK, everything works all right
sdl+LablGL in interpreted mode => Failure
sdl+glMLite in native code => Failure
sdl+LablGL in native code => Failure

The exception is raised by the function Sdlvideo.set_video_mode which is a 
function from ocamlsdl, so it is very strange that changing the OpenGL 
bindings changes the behaviour!

Here are respectively the commands I use:

ocaml -I +glMLite GL.cma bigarray.cma -I +sdl sdl.cma test.ml
ocaml -I +lablGL lablgl.cma bigarray.cma -I +sdl sdl.cma test.ml 
ocamlopt -I +glMLite GL.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o test
ocamlopt -I +lablGL lablgl.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o test


Does someone have an idea or a clue about how to fix the problem?
(The code is right, otherwise the first test wouldn't work.
Also the exact equivalent in pure C does work right.)

================================
let display() =
  GlClear.clear [`color];
  GlDraw.begins `triangles;
  GlDraw.color (0.0, 1.0, 0.0);
  GlDraw.vertex2 (-0.5, -0.5);
  GlDraw.vertex2 ( 0.0,  0.5);
  GlDraw.vertex2  (0.5, -0.5);
  GlDraw.ends();
  Sdlgl.swap_buffers()

let () =
  Sdl.init [`EVERYTHING];
  let _ = Sdlvideo.set_video_mode ~w:640 ~h:480 ~bpp:0 [`OPENGL; `DOUBLEBUF] 
in
  let rec loop() =
    match Sdlevent.poll() with
    | Some Sdlevent.KEYDOWN { Sdlevent.keysym = Sdlkey.KEY_ESCAPE }
    | Some Sdlevent.QUIT -> ()
    | _ -> display(); loop()
  in
  loop();
  Sdl.quit()
================================
open GL
let display() =
  glClear [GL_COLOR_BUFFER_BIT];
  glBegin GL_TRIANGLES;
  glColor3 0.0 1.0 0.0;
  glVertex2 (-0.5) (-0.5);
  glVertex2 ( 0.0) ( 0.5);
  glVertex2 ( 0.5) (-0.5);
  glEnd();
  Sdlgl.swap_buffers()

let () =
  Sdl.init [`EVERYTHING];
  let _ = Sdlvideo.set_video_mode ~w:640 ~h:480 ~bpp:0 [`OPENGL; `DOUBLEBUF] 
in
  let rec loop() =
    match Sdlevent.poll() with
    | Some Sdlevent.KEYDOWN { Sdlevent.keysym = Sdlkey.KEY_ESCAPE }
    | Some Sdlevent.QUIT -> ()
    | _ -> display(); loop()
  in
  loop();
  Sdl.quit()
================================

Re: [Caml-list] ocaml+sdl+opengl ?

[Daniel Bünzli]

You did not specify the platform but on osx 10.6.3 sdl+lablgl works.

More precisely

> sdl+LablGL in interpreted mode => Failure

Works but you need to make a custom toplevel (see ocamlsdl's readme about osx).

$ ocamlmktop -I +lablGL -I +sdl -custom -o ocamlsdl lablgl.cma
bigarray.cma sdl.cma
$ ./ocamlsdl -I +lablGL -I +sdl test.ml

> sdl+LablGL in native code => Failure

Works here with

$ ocamlopt -I +lablGL lablgl.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o test

Best,

Daniel

Re: [Caml-list] ocaml+sdl+opengl ?

[Florent Monnier]

Le dimanche 11 avril 2010 19:53:29, Florent Monnier a écrit :
> Hi,
> I'm trying to use ocamlsdl for the windowing of an OpenGL application.
> 
> You will find below 2 test files, one using LablGL and one using glMLite.
> 
> I have made these test:
> 
> sdl+glMLite in interpreted mode => OK, everything works all right
> sdl+LablGL in interpreted mode => Failure
> sdl+glMLite in native code => Failure
> sdl+LablGL in native code => Failure
> 
> The exception is raised by the function Sdlvideo.set_video_mode which is a
> function from ocamlsdl, so it is very strange that changing the OpenGL
> bindings changes the behaviour!
> 
> Here are respectively the commands I use:
> 
> ocaml -I +glMLite GL.cma bigarray.cma -I +sdl sdl.cma test.ml
> ocaml -I +lablGL lablgl.cma bigarray.cma -I +sdl sdl.cma test.ml
> ocamlopt -I +glMLite GL.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o test
> ocamlopt -I +lablGL lablgl.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o
>  test
> 
> 
> Does someone have an idea or a clue about how to fix the problem?
> (The code is right, otherwise the first test wouldn't work.
> Also the exact equivalent in pure C does work right.)

So I have made another test. I have copied the following files from the sources 
of ocamlsdl from its directory ocamlsdl-0.7.2/src/ into the same directory 
where are located the test files (which are at the end of this email):

common.c         sdlgl_stub.c        sdl.ml           sdlvideo_flag.c
common.h         sdlinit_flag.c      sdlmouse.ml      sdlvideo_flag.h
config.h         sdlinit_flag.h      sdlmouse_stub.c  sdlvideo.ml
files            sdljoystick.ml      sdlmouse_stub.h  sdlvideo_stub.c
sdlevent.ml      sdljoystick_stub.c  sdlrwops_stub.c  sdlvideo_stub.h
sdlevent_stub.c  sdlkey.ml           sdlrwops_stub.h
sdlgl.ml         sdlkey_stub.c       sdl_stub.c


Then I have compiled everything with :

ocamlopt -o test bigarray.cmxa \
  sdl.ml sdlmouse.ml sdljoystick.ml sdlkey.ml \
  sdlevent.ml sdlvideo.ml sdlgl.ml \
  $GL_BINDINGS test.ml \
  -ccopt "`sdl-config --cflags`" \
  sdl_stub.c sdlgl_stub.c sdlvideo_stub.c sdlkey_stub.c sdlevent_stub.c \
  sdlmouse_stub.c sdljoystick_stub.c common.c sdlrwops_stub.c \
  -cclib "-lGL `sdl-config --libs`"

where I switch the OpenGL bindings with:

GL_BINDINGS="-I +glMLite GL.cmxa"
GL_BINDINGS="-I +lablGL lablgl.cmxa"

here the results I get:

=> with LablGL it fails again.
=> with glMLite now it works in native code too.

Again the SDL part fails with one OpenGL bindings and not with the other one.
What could explain this ?

Also with glMLite and in native mode, using ocamlsdl as a lib fails, and 
compiling locally ocamlsdl's source files succeeds.
What could explain this ?


> ================================
> let display() =
>   GlClear.clear [`color];
>   GlDraw.begins `triangles;
>   GlDraw.color (0.0, 1.0, 0.0);
>   GlDraw.vertex2 (-0.5, -0.5);
>   GlDraw.vertex2 ( 0.0,  0.5);
>   GlDraw.vertex2  (0.5, -0.5);
>   GlDraw.ends();
>   Sdlgl.swap_buffers()
> 
> let () =
>   Sdl.init [`EVERYTHING];
>   let _ = Sdlvideo.set_video_mode ~w:640 ~h:480 ~bpp:0 [`OPENGL;
>  `DOUBLEBUF] in
>   let rec loop() =
>     match Sdlevent.poll() with
> 
>     | Some Sdlevent.KEYDOWN { Sdlevent.keysym = Sdlkey.KEY_ESCAPE }
>     | Some Sdlevent.QUIT -> ()
>     | _ -> display(); loop()
> 
>   in
>   loop();
>   Sdl.quit()
> ================================
> open GL
> let display() =
>   glClear [GL_COLOR_BUFFER_BIT];
>   glBegin GL_TRIANGLES;
>   glColor3 0.0 1.0 0.0;
>   glVertex2 (-0.5) (-0.5);
>   glVertex2 ( 0.0) ( 0.5);
>   glVertex2 ( 0.5) (-0.5);
>   glEnd();
>   Sdlgl.swap_buffers()
> 
> let () =
>   Sdl.init [`EVERYTHING];
>   let _ = Sdlvideo.set_video_mode ~w:640 ~h:480 ~bpp:0 [`OPENGL;
>  `DOUBLEBUF] in
>   let rec loop() =
>     match Sdlevent.poll() with
> 
>     | Some Sdlevent.KEYDOWN { Sdlevent.keysym = Sdlkey.KEY_ESCAPE }
>     | Some Sdlevent.QUIT -> ()
>     | _ -> display(); loop()
> 
>   in
>   loop();
>   Sdl.quit()
> ================================

Re: [Caml-list] ocaml+sdl+opengl ?

[Daniel Bünzli]

> OK, so I guess the problem is specific for Linux

Well apparently not, I just tried on my netbook and sdl+lablgl works
perfectly (both byte and native).

> uname -a
Linux minidip 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 05:23:09 UTC
2010 i686 GNU/Linux

Best,

Daniel

Re: [Caml-list] ocaml+sdl+opengl ?

[Florent Monnier]

> You did not specify the platform but on osx 10.6.3 sdl+lablgl works.

I'm using Linux.
(and glMLite does work on MacOSX too)


> > sdl+LablGL in interpreted mode => Failure
> 
> Works but you need to make a custom toplevel (see ocamlsdl's readme about
>  osx).
> 
> $ ocamlmktop -I +lablGL -I +sdl -custom -o ocamlsdl lablgl.cma
> bigarray.cma sdl.cma
> $ ./ocamlsdl -I +lablGL -I +sdl test.ml
> 
> > sdl+LablGL in native code => Failure
> 
> Works here with
> 
> $ ocamlopt -I +lablGL lablgl.cmxa bigarray.cmxa -I +sdl sdl.cmxa test.ml -o
>  test

OK, so I guess the problem is specific for Linux


-- 
Best,
Florent

Re: [Caml-list] ocaml+sdl+opengl ?

[Florent Monnier]

> > OK, so I guess the problem is specific for Linux
> 
> Well apparently not, I just tried on my netbook and sdl+lablgl works
> perfectly (both byte and native).
> 
> > uname -a
> 
> Linux minidip 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 05:23:09 UTC
> 2010 i686 GNU/Linux

I use Mandriva-Linux.

I have the same problem with the official mandriva package of ocamlsdl,
and with ocamlsdl compiled from sources.
What could be the problem?

-- 
Best,
Florent