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[Massena]

Hello, I'm just starting to make a simple game in Allegro using c++ when, sadly, I encountered an early bump on the road. Page tearing. 
Every 3 or so seconds the animation (a simple circle moving around) gets all choppy as if it skips some frames or the circle gets divided for a moment. I can't really explain, but it is annoying and I've tried a lot and didn't solve my problem.
I posted a topic which you can read at http://www.allegro.cc/forums/thread/594506/0 on allegro.cc and I didn't solve the tearing. I tried double buffering, higher resolution timers and vsync but ended up running out of ideas.
Any possible solutions? Something silly I am missing?
Thanks in advance! 

P.S.: You may notice my last reply at the allegro.cc post is quite dumb but I was getting frustrated and thought I could live with the tearing. I cannot, if I continue to experience this I'll just switch to SDL and pretend nothing ever happened. 

[spellcaster]

Create your buffers in vid mem, this should allow for real page flipping.
You could also choose to use AllegroGL (which is IMO now a part of the normal allegro package).

If you go for vid mem, make sure to reload the buffers on certain events (like alt-tabbing) since this may corrupt the vid mem.
There's agood example for vid buffers in the allegro doc, IIRC.

[Massena]

You mean I should use create_video_bitmap? 'Cause I'm kinda lost on what you said 
Edit: I tried just to replace "buffer = create_bitmap (screen->w, screen->h);" with "buffer = create_video_bitmap (screen->w, screen->h);" and that was a complete failure :D Hope that was not what you meant!

[spellcaster]

That's what I meant.
But it's not quite as easy as that

The first buffer you create will point to the actual visible screen. So you'll need to create two buffers.

Take a look at the allegro docs for "show_video_bitmap", there's an example on how to use video bitmaps for page flipping.

Please note that show_video_bitmapwill work only in fullscreen mode. If your game will run both windowed and fullscreen, you should use a normal blit in windowed mode.

[Massena]

Oh! I tried page flipping, it gets all choppy in fullscreen, even the allegro example for page flipping doesn't work well! Maybe it has something to do with me using a mac. 

[Madgarden]

What's your framerate set to? If it matches your refresh rate, then you'll see some jittering as it won't be quite exactly in sync. Try a framerate of 50 or 100, double buffered.

Not sure anyone else mentioned this yet either, but triple buffering should give you the silky smooth scrolling of legend.

[spellcaster]

Not sure, how well coded the OSX port of allegro is.
IMO it might have some issues. Which would also explain why the page flipping doesn't work.

I'd say Madgardens triple buffer idea might be worth a try. On the other hand - if you have smooth updates, and the tearing is only from time to time, triple buffering might not really help that much

[Massena]

Meh, I give up.  Too much hassle, I'll just use SDL, I found a great tutorial and it seems easier, at least from the outside!
Thanks anyway!