Building a game loop (sort of)

Building a game loop (sort of)

[C. Fr]

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Hello everyone,

 

I’m building a small fractal visualisation app in ocaml, but I encounter
many problems with the graphics package.

 

First, plot (size_x / 2) (size_y / 2) doesn’t actually plot in the middle of
the screen… Any idea why?

 

Then, using the following code

 

if key_pressed () then

        begin

            match read_key () with

            | 'q' -> raise Exit

            | 'o' -> scale := !scale *. 2.

            | 'i' -> scale := !scale /. 2.

            | 'l' -> mid_x := !mid_x + 100

            | 'r' -> mid_x := !mid_x - 100

            | 'u' -> mid_y := !mid_y + 100

            | 'd' -> mid_y := !mid_y - 100

            | _ -> ()

        end

    done;

in a while true loop behaves randomly, ignoring some key presses, and
repeating some… Is there something that I did wrong?

 

Thanks a lot,

Andrea.

 

 

 

 


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Re: [Caml-list] Building a game loop (sort of)

[Stas Miasnikou]

On 3/21/10, C. Fr <newsgroups.fr@gmail.com> wrote:
> I’m building a small fractal visualisation app in ocaml, but I encounter
> many problems with the graphics package.
>
> First, plot (size_x / 2) (size_y / 2) doesn’t actually plot in the middle of
> the screen… Any idea why?

What are size_x and size_y, what you got, and what you are supposed to get?

> Then, using the following code
>
> if key_pressed () then
>         begin
>             match read_key () with
>             | 'q' -> raise Exit
>             | 'o' -> scale := !scale *. 2.
>             | 'i' -> scale := !scale /. 2.
>             | 'l' -> mid_x := !mid_x + 100
>             | 'r' -> mid_x := !mid_x - 100
>             | 'u' -> mid_y := !mid_y + 100
>             | 'd' -> mid_y := !mid_y - 100
>             | _ -> ()
>         end
>     done;
>
> in a while true loop behaves randomly, ignoring some key presses, and
> repeating some… Is there something that I did wrong?

Stas

Re: [Caml-list] Building a game loop (sort of)

[Yang Ye]

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For 2nd question, skipping the outer if? Because read_key is waiting and
queuing they keypresses already.

On Mon, Mar 22, 2010 at 5:26 AM, Stas Miasnikou <stas.miasnikou@gmail.com>wrote:

> On 3/21/10, C. Fr <newsgroups.fr@gmail.com> wrote:
> > I’m building a small fractal visualisation app in ocaml, but I encounter
> > many problems with the graphics package.
> >
> > First, plot (size_x / 2) (size_y / 2) doesn’t actually plot in the middle
> of
> > the screen… Any idea why?
>
> What are size_x and size_y, what you got, and what you are supposed to get?
>
> > Then, using the following code
> >
> > if key_pressed () then
> >         begin
> >             match read_key () with
> >             | 'q' -> raise Exit
> >             | 'o' -> scale := !scale *. 2.
> >             | 'i' -> scale := !scale /. 2.
> >             | 'l' -> mid_x := !mid_x + 100
> >             | 'r' -> mid_x := !mid_x - 100
> >             | 'u' -> mid_y := !mid_y + 100
> >             | 'd' -> mid_y := !mid_y - 100
> >             | _ -> ()
> >         end
> >     done;
> >
> > in a while true loop behaves randomly, ignoring some key presses, and
> > repeating some… Is there something that I did wrong?
>
> Stas
>
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-- 
Regards,
Yang Ye

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