VOGONS


First post, by xjas

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When running stuff that uses a 15/16 or 24-bit mode, the colors go completely off. It's almost like the blue goes missing. This only happens on the display and does not appear in screenshots taken with crtl+f5. (I took the following screenshots using OS/X's desktop screen grabber.) It does occur regardless of whether you're running in a window or full-screen.

I'm using Dominus's SVN build from about two weeks ago.

Here's Scorcher (Zyrinx, 1996), in 640x400x256:

scor1.png
Filename
scor1.png
File size
168.14 KiB
Views
915 views
File license
Fair use/fair dealing exception

And in 640x400x16bit:

scor2.png
Filename
scor2.png
File size
124.44 KiB
Views
915 views
File license
Fair use/fair dealing exception

Incidentally the menu & splash screen in this game appears with a blue background, it's supposed to be black. I don't know what video mode this is in unfortunately:

scor3.png
Filename
scor3.png
File size
60.75 KiB
Views
915 views
File license
Fair use/fair dealing exception

Here's another example, Sunflower by Pulse (1997) - also 16bit:

sunflow1.png
Filename
sunflow1.png
File size
87.64 KiB
Views
915 views
File license
Fair use/fair dealing exception
sunflow2.png
Filename
sunflow2.png
File size
58.08 KiB
Views
915 views
File license
Fair use/fair dealing exception

(This is what it's supposed to look like)

I should probably have reported years ago since it's been in the code since at least since 2014 when I got my Macbook, maybe earlier. I've been running SVN versions the whole time and updating it every now & then.

Some (hopefully) relevant sections from my DOSBox.conf. Note that I'm using svga_s3 & opengl render:

[sdl]
# fullscreen: Start dosbox directly in fullscreen. (Press ALT-Enter to go back)
# fulldouble: Use double buffering in fullscreen. It can reduce screen flickering, but it can also result in a slow DOSBox.
# fullresolution: What resolution to use for fullscreen: original, desktop or a fixed size (e.g. 1024x768).
# Using your monitor's native resolution with aspect=true might give the best results.
# If you end up with small window on a large screen, try an output different from surface.
# windowresolution: Scale the window to this size IF the output device supports hardware scaling.
# (output=surface does not!)
# output: What video system to use for output.
# Possible values: surface, overlay, opengl, openglnb.
# autolock: Mouse will automatically lock, if you click on the screen. (Press CTRL-F10 to unlock)
# sensitivity: Mouse sensitivity.
# waitonerror: Wait before closing the console if dosbox has an error.
# priority: Priority levels for dosbox. Second entry behind the comma is for when dosbox is not focused/minimized.
# pause is only valid for the second entry.
# Possible values: lowest, lower, normal, higher, highest, pause.
# mapperfile: File used to load/save the key/event mappings from. Resetmapper only works with the default value.
# usescancodes: Avoid usage of symkeys, might not work on all operating systems.

fullscreen=false
fulldouble=false
fullresolution=1280x800
windowresolution=original
output=opengl
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper-SVN.map
usescancodes=true

[dosbox]
# language: Select another language file.
# machine: The type of machine DOSBox tries to emulate.
# Possible values: hercules, cga, tandy, pcjr, ega, vgaonly, svga_s3, svga_et3000, svga_et4000, svga_paradise, vesa_nolfb, vesa_oldvbe.
# captures: Directory where things like wave, midi, screenshot get captured.
# memsize: Amount of memory DOSBox has in megabytes.
# This value is best left at its default to avoid problems with some games,
# though few games might require a higher value.
# There is generally no speed advantage when raising this value.

language=
machine=svga_s3
captures=~/dosbox_caps
memsize=30

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 1 of 5, by xjas

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Here's SEA image viewer running in a 24-bit mode. Same thing.

24bit.png
Filename
24bit.png
File size
573.33 KiB
Views
913 views
File license
Fair use/fair dealing exception

Original image:

20121002.JPG
Filename
20121002.JPG
File size
81.09 KiB
Views
913 views
File license
Fair use/fair dealing exception

Note that I'm running OS/X 10.9.5. I can also confirm this happens on 10.8.x. I don't have a machine running any newer OS/X (& hopefully never will. 😜)

Edit: to answer the obvious next question, the only other video device I can get these modes to work in is vesa_oldVBE and yes, it occurs in that as well.

Edit 2: this DOES NOT happen in Boxer (latest version) but I don't know what they're doing differently.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 2 of 5, by xjas

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Edit 3: also happens using the SURFACE & OVERLAY renderers.

ALSO, possibly related: in Surface, if I move the window from one monitor to the other, this happens. I don't see this in any other mode.

surface.png
Filename
surface.png
File size
24.83 KiB
Views
908 views
File license
Fair use/fair dealing exception

Sorry for the infospam, I didn't look too hard into it previously so these are all new discoveries for me.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 3 of 5, by xjas

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FINAL UPDATE: It turns out this is a well known bug and I just somehow completely failed to find it when I searched. This thread can probably be deleted. Sorry about that. 🙁

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 5 of 5, by Dominus

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There is an unofficial patch for SDL2 in the forum. And yes, well known bug and I have no idea why boxer doesn't have it but then boxer doesn't care about upstream.

Windows 3.1x guide for DOSBox
60 seconds guide to DOSBox
DOSBox SVN snapshot for macOS (10.4-11.x ppc/intel 32/64bit) notarized for gatekeeper