Dosbox scrolling screen errors

[Dragu]

I was just having such problem, and the reason is that in the standard dosbox.conf, [cpu] section, cycles are put as cycles=max. This seems to have negative influence on some older screen scrolling games. Including screen tearing on vertical scrolling. In general the problem resolve with cycles=auto in a local dosbox.cfg file.

[voljega]

@dragu what is the problem more precisely beside tearing ?

[Dragu]

@voljega
That you have no smooth scrolling in jump&run games that use this technique, that you shadow frames or half frames.

[voljega]

@dragu ok do you have some example of games ?

[lmerckx]

Indeed, even if cycles=max is good for most of the games. Some others need adaptations.

I played some "platform" games which need cycles=auto.
Ultima 6 and 7 need to force a fixed cycles.

Don't hesitate to test some values and change your game dosbox.conf.

[Dragu]

@lmerckx
@voljega
J'ai eu le cas avec "Captain Dynamo" et donc je pense que ce n'est pas le seul jeu dans les premiers side-scrollers apparus sur le marché. L'effet est spectalulaire. De même j'ai constaté que dans cet jeu mettant scaler=none au lieu de scaler=normalx2 donne une bien meilleure image.

[voljega]

@dragu cool merci !

a propos je me souviens qu'au débit où on parlait de dosbox tu avais conseillé vsync = false, c'est parce que le pi est pas assez puissant ? parce que du coup y'a pas mal de tearing dans beaucoup de jeu

[Dragu]

@voljega
J'ai constaté que vsync=true n'a aucun effet positif sur le tearing. alors autant ne pas le mettre. Bon, peut-être d'autres personnes ont trouvé des effets positifs.
En tout cas, dans les forums dosbox, ce problème est souvent adressé, et je n'ai jamais lu que cela pouvait venir de cycles=max. Il paye donc d'essayer un peu tout.

[lmerckx]

OK, I will try too with the scaler value.
OK, j'essaierai aussi avec le scaler.

Thank you.

[voljega]

@dragu OK merci

En tout cas c'est pas si facile de bien configurer DosBox sur Pi3 pour chaque jeu individuellement, beaucoup de ralentissements y compris de façon surprenant sur des jeux plutôt vieux... les vidéos d'intro ou les cinématiques il aime pas trop aussi alors que souvent le jeu tourne mieux

[Dragu]

@voljega
Tu sais quelle version est intégré pour le moment ?

[voljega]

@dragu dans le post du blog sur la dernière mise à jour :

DosBox :
Mis à jour en version 0.74 r4063. Merci à lmerckx pour son travail.

D'ailleurs peut-être que @lmerckx peut nous dire plus en détail quels sont les changements apportés ?

[lmerckx]

@voljega Pour le log complet des modifications, voir ici: https://sourceforge.net/p/dosbox/code-0/commit_browser
Il s'agit des commits entre 3989 à 4063 ...

En résumé, beaucoup de petites corrections mineures (notamment du deb****r) mais une amélioration de la stabilité en mode cycles=auto (si je comprends bien).

[Dragu]

@lmerckx
@voljega
Something disturbing is the joystick emulation in Dosbox. You have games that have weird behaviour with automatic joystick emulation offered by Dosbox. So, you would prefer to use keyboard and define your own joystick in mapping keyboard keys to the joystick directions. ok ?
But no way to avoid. If you put joystick=auto he emulate an game intern joystick. If you put joystick=none, you cannot remap them to keys in keymapper. You can just hope that the game offer you the choice. Their should be a 3rth way joystick=noemu ore something like this, but still useable in the keymapper.

[lmerckx]

@Dragu My strategy is to use the joystick in game when possible. But with configuration 'timed=false' (it avoids undesired moves).
The remaining buttons (not used in game) are then mapped to keyboard for full usage of joystick.
Works with Doom and Wolfenstein 3D, for instance.

When mapping keys to joystick axis, you loose some feature: moving in X and Y axis in the same time is not possible.
This problem can be resolve by changing an hard-coded constant in the game which represents the dead zone of the joystick (25000). But I haven't found the perfect value for the moment.
When mapping movement keys, I prefer to map them to joystick's hat. No problem in that case.

[Dragu]

Thanks !
Its always a challenge I have now Captain Dynamo controls configurated, so in this game simultane jumping + joystick up should give long jump. Trying with joystick=auto was not working in putting jump and direction key UP together on the same button. I already did this, here he would jump ore move left/right, but not both together.
But with joystick=fcs Y- and Y+ axe not working on joystick. But mapping together Y- with jump on Jump button everything correct and simultane working. Crazy.

[lmerckx]

@Dragu On my side, I've just tested 'scaler=none' and it's really better !
Thanks too ...

What DosBox still needs to be 100% usable on Recalbox is a virtual (on-screen) keyboard.
I've searched a bit but I found no easy solution ...