NullDC Flicker when Compiling Parallax Examples

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KingCrazy
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NullDC Flicker when Compiling Parallax Examples

Post by KingCrazy »

Hello!

I was recently trying to delve deeper into the world of 3D Dreamcast graphics and decided to check out the numerous different options available. I was working solely with the PVR for a bit until I (quite embarrassingly) couldn't figure out how to set up the camera and perspective (that's an issue for another time, though!).

I was looking into OpenGL, despite a lot of people around here saying it's slow and clunky, and also alternatively stumbled upon the parallax tutorials. I wanted to give parallax a shot, so I compiled two of the examples (delay_cube and rotocube to be exact). Unfortunately when I went to test them in NullDC, I got this really annoying flickering or flashing effect.

Minor seizure warning (it looks worse when running in real time than it does in the gif), but here it is if anyone cares to see

I'm running Windows and compiling through MSYS2 (making sure to run it as MINGW32. I had previously been using Cygwin but OpenGL tests were crashing in NullDC, leaving me to discover my toolchain was broken. Figured I might as well start fresh so I transferred over to MSYS2 from there). I also tried compiling through a Linux version of the toolchain that I setup in a virtual machine, and got similar results.

Is this just an issue with Parallax? Is this a NullDC issue (I don't physically have a dreamcast with me to test this on, unfortunately)? Or did I mess something up?

Any help or suggestions would be appreciated! Thanks!
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BlueCrab
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Re: NullDC Flicker when Compiling Parallax Examples

Post by BlueCrab »

It is an most likely an issue with NullDC. There are other emulators out there you could try, such as Reicast (the successor to NullDC) or Demul.

That said, testing things in an emulator is usually not the best approach, since it's already difficult enough to debug Dreamcast code without having the additional potential of the emulator being the one causing the bugs you might be seeing.
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Re: NullDC Flicker when Compiling Parallax Examples

Post by kazade »

FWIW I see the same flickering on NullDC running under WINE on Linux. I thought it might have been a bug in my OpenGL library but apparently not!
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Re: NullDC Flicker when Compiling Parallax Examples

Post by KingCrazy »

BlueCrab wrote: Mon Aug 06, 2018 12:25 am It is an most likely an issue with NullDC.
That did it! Thank you! I was having trouble finding alternative Dreamcast emulators to test it on. Reicast ended up having the exact same problem, but Demul seems to work perfectly fine for both the rotocube and delay_cube example! Only downside is that Demul seems to have quite a bit more lag than NullDC, but at least there's no flicker!
kazade wrote: Mon Aug 06, 2018 1:27 am I thought it might have been a bug in my OpenGL library but apparently not!
Ironically I'm not getting any flicker with OpenGL in NullDC (though I'm testing libGL before trying out your GLdc library), just with Parallax. Very strange, though!
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