VOGONS


First post, by MrFlibble

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A while ago I found a demo of a fighting game that was apparently never completed and released called Ultimate Warrior by AD Studios (presumably a dev team from the UK): uwarrior.zip

Since I mostly use SVN Daum for testing it ran fine for me but when I tested the demo with vanilla DOSBox (latest release 0.74-3), I discovered noticeable screen flickering, both of character sprites and the background. If I turn background animation off only the character sprites flicker. Further tests showed no flickering problems with DOSBox ECE, so this is only observed in vanilla DOSBox.

Other settings I used are cycles=auto 7800 100% limit 26800. The demo runs very robustly at this setting. Changing cycles does not seem to affect flickering in any way. For the sake of a test I dropped this to cycles=auto 7800 50% limit 9600, but only got a speed reduction with flickering still happening.

Changing output type in [sdl] also does not do anything to improve the situation.

The game documentation says it needs a VBE 2.0 compatible card. Which is probably why trying to switch DOSBox to vesa_nolfb or vesa_oldvbe caused the demo not to run at all.

The documentation also mentioned possible flickering (on a real period machine) and suggested to lower game speed in options to fix that. However, I tried every possible speed setting to no avail.

Is there any way to fix the issue in the latest release of vanilla DOSBox? (other than hacking the exe or stuff like that I mean)

Last edited by MrFlibble on 2020-11-01, 20:21. Edited 1 time in total.

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Reply 1 of 4, by ripsaw8080

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Please always test problems in a straight SVN build. Unofficial source builds are not supported here, and as a point of reference they are better compared to SVN than to 0.74. You can get a straight SVN build at the ECE site just as easily as the ECE build.

Your cycle limit is possibly related to the issue, and you did not mention increasing the limit. For example, the default setting of cycles=auto (i.e. no limit) does not flicker in 0.74-3 on my system, but your results may vary.

Note that machine=vesa_nolfb does support VESA 2.0, just without LFB. However, the game appears to assume LFB and crashes when there is none.

A key factor in avoiding flicker regardless of cycles is probably the "wait for retrace" feature of VBE, which is not implemented in 0.74 but is implemented in SVN. In 0.74 you can load UNIVBE 5.3a to get the wait for retrace feature.

Reply 2 of 4, by MrFlibble

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ripsaw8080 wrote on 2020-11-01, 16:06:

Please always test problems in a straight SVN build. Unofficial source builds are not supported here

I know, I only mentioned them because they did not display this behaviour as opposed to the latest official vanilla release. My intention was to find out if the flicker issue could be resolved specifically in v0.74-3.

I changed the topic title to remove references to unofficial forks, so as not to set a precedent.

ripsaw8080 wrote on 2020-11-01, 16:06:

Your cycle limit is possibly related to the issue, and you did not mention increasing the limit.

Sorry, I forgot to mention that I also tested with a limit at 77000 cycles with the same results.

I just tried auto cycles, and while the flickering is gone, in addition to rather high speed overall (even at the lowest in-game speed setting) the animation of the characters gets very jaggy.

Using fixed cycles seems to have the same effect as limiting them to the same amount.

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Reply 3 of 4, by ripsaw8080

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MrFlibble wrote on 2020-11-01, 20:23:

My intention was to find out if the flicker issue could be resolved specifically in v0.74-3.

Please read the last sentence of my previous comment.