[SDL] SDL Digest, Vol 3, Issue 17

Wed Mar 7 19:48:19 PST 2007

Simple Again,  to animate using SDL, When you load your images load them
into an array, something like ths pseudo code

SDL_Surface * FootFrames[2];

     FootFrames[1]  = LoadIMG("FootImage1")
     FootFrames[2]  = LoadIMG("FootImage2")
     int       footAnim=0;

on your key events

   if key pressed
      footAnim++;

on your draw bitmaps part

   *SDL_BlitSurface*(FootFrames[footAnim&1], NULL, Screen, NULL);

the important part here is that your footAnim just keeps incrementing but
the footAnim&1 is a bit wise AND, giving you only 0 or 1.

I hope this helps

Trish

PS please dont anyone say i have missed my error checks :p

On 3/8/07, sdl-request at lists.libsdl.org <sdl-request at lists.libsdl.org>
wrote:
>
> Send SDL mailing list submissions to
>        sdl at lists.libsdl.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>        http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org
> or, via email, send a message with subject or body 'help' to
>        sdl-request at lists.libsdl.org
>
> You can reach the person managing the list at
>        sdl-owner at lists.libsdl.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of SDL digest..."
>
>
> Today's Topics:
>
>   1. SDL_CondSignal usage (sanjay kumar gupta)
>   2. Re: SDL_CondSignal usage (Alexis Naveros)
>   3. Quick Question about animation. (Lamonte(Scheols/Demonic))
>   4. Re: Quick Question about animation. (Scott Harper)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: 7 Mar 2007 20:02:00 -0000
> From: "sanjay kumar gupta" <sanjay417 at rediffmail.com>
> Subject: [SDL] SDL_CondSignal usage
> To: sdl at lists.libsdl.org
> Message-ID: <20070307200200.17794.qmail at webmail99.rediffmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
> man page of function SDL_CondSignal(cond) says that it will Restart a
> thread which is waiting on condition variable (here it is cond).
> What if one thread is calling function SDL_CondSignal(cond) and none of
> the other threads has called SDL_CondWait(cond,mutex).
> what will be the effect of calling SDL_CondSignal(cond) in this case even
> if no one is waiting on this condition variable?
>
> Thanks & regards,
> Sanjay
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> http://lists.libsdl.org/pipermail/sdl-libsdl.org/attachments/20070307/8629991e/attachment-0001.html
>
> ------------------------------
>
> Message: 2
> Date: Wed, 07 Mar 2007 15:34:26 -0500
> From: Alexis Naveros <alexis at rayforce.net>
> Subject: Re: [SDL] SDL_CondSignal usage
> To: sdl at lists.libsdl.org
> Cc: "A list for developers using the SDL library. \(includes
>        SDL-announce\)" <sdl at lists.libsdl.org>
> Message-ID: <20070307153426.ceafa9e4.alexis at rayforce.net>
> Content-Type: text/plain; charset=US-ASCII
>
> >   man page of function SDL_CondSignal(cond) says that it will Restart a
> thread which is waiting on condition variable (here it is cond).
> >  What if one thread is calling function SDL_CondSignal(cond) and none of
> the other threads has called SDL_CondWait(cond,mutex).
> > what will be the effect of calling SDL_CondSignal(cond) in this case
> even if no one is waiting on this condition variable?
>
> Same as with Pthreads signal surely, SDL_CondSignal has no effect and
> execution continues. After the condition variable has been signaled, any
> threading waiting on it will block as usual.
>
> Alexis
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 7 Mar 2007 16:33:19 -0600
> From: "Lamonte(Scheols/Demonic)" <scheols at gmail.com>
> Subject: [SDL] Quick Question about animation.
> To: "A list for developers using the SDL library. (includes
>        SDL-announce)"  <sdl at lists.libsdl.org>
> Message-ID:
>        <5b0fce7a0703071433ya66db91ob2ad688b3753b16e at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hello,
> I was wondering whats the best way to switch between 2 image frames
> every time I would press a key.  For example, If I loaded 2 bitmaps
> one will have its foot back and the other would have its foot forward
> so if I would to keep running the frames back and forth it would look
> like my sprite was walking.  Any suggestions on the BEST way to do
> this?
>
> Thanks in advanced for any suggestions giving.
> -Lamonte
>
> --
> Join phpdiscovery.com Now!
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 7 Mar 2007 16:09:39 -0700
> From: Scott Harper <lareon at comcast.net>
> Subject: Re: [SDL] Quick Question about animation.
> To: "A list for developers using the SDL library. (includes
>        SDL-announce)"  <sdl at lists.libsdl.org>
> Message-ID: <4BCB6C1E-560F-4BB2-A9D7-9E13614EB186 at comcast.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
>
> On Mar 7, 2007, at 3:33 PM, Lamonte(Scheols/Demonic) wrote:
>
> > Hello,
> > I was wondering whats the best way to switch between 2 image frames
> > every time I would press a key.  For example, If I loaded 2 bitmaps
> > one will have its foot back and the other would have its foot forward
> > so if I would to keep running the frames back and forth it would look
> > like my sprite was walking.  Any suggestions on the BEST way to do
> > this?
>
> Unfortunately (as I'm sure many have discovered and I am currently
> discovering), there's no "best" way to do something like this.  You
> could set a variable and draw one or the other image based on that
> variable's value (meaning one more if() statement each frame), or you
> could set some pointer variable to a drawing structure to point to a
> different image each time it needs to switch...  Those are the only
> two reasonable ones I can come up with.  The others a far more
> obscure and unlikely.
>
> Do either of those help at all?
>
> I think a lot of "best" depends on how you're structuring your
> entities, also.
>
> -- Scott
>
>
> ------------------------------
>
> _______________________________________________
> SDL mailing list
> SDL at lists.libsdl.org
> http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org
>
>
> End of SDL Digest, Vol 3, Issue 17
> **********************************
>

-- 
In a time of universal deceit, telling the truth is a revolutionary act.

Trish & Thy also Available on

Skype tranmaithy63,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.libsdl.org/pipermail/sdl-libsdl.org/attachments/20070308/29f2483a/attachment-0001.htm 