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drwonky / cgax16demo

CGA, EGA, VGA 160x100 16 color pseudo graphics mode demo code
MIT License
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VGA 160x100 demo not working #1

Open viti95 opened 3 years ago

viti95 commented 3 years ago

I've tried the CGA16DMO.EXE file on real hardware (VGA cards) and emulators (Dosbox-X), and in both cases the screen stays in blank. It works fine with CGA and EGA video modes.

drwonky commented 3 years ago

I just tested it under dosbox and it worked fine for me. I've added my dosbox config file to the repo so you can try it.

dosbox-0.74-3.conf

It's been a while since I wrote this, but the only VGA cards I could have tested it on are a Video Seven Fastrite VGA and Tseng ET4000/W32p. The Tseng card is in the DOS computer I have setup permanently, the Video Seven is only used on the test bench computer when I set it up.

drwonky commented 3 years ago

What VGA card did you test this on? I'm guessing it might be incorrectly detecting the video card if it isn't working. The default choice is VGA, so it would be incorrectly detecting EGA or CGA instead. The dosbox config I use is set to emulate an s3 video card.

viti95 commented 3 years ago

I've tested with these VGA cards

All of them had blank screen. The monitor reports 720x400 mode at 70hz with correct signal, but just all blank. I've tested also with latest version of Dosbox-X (vgaonly, also blank screen) and an older version of Dosbox (which shows fine the demo)

drwonky commented 3 years ago

Can you attach your dosbox config file for the version that doesn't work? What is the exact name and version number of the dosbox that doesn't work?

Franticware commented 2 years ago

I have tested it on S3 Virge GX PCI, it showed black screen only.

drwonky commented 1 year ago

I've got another ISA VGA card coming, I will test it. I got a Compaq CGA card and the code works fine on a real CGA. This also works on an Everex EGA card. I've got a couple laptops with Cirrus 65xxx chips I can test on.