Medabots BG2 pixelation issue

[Trivial Man]

I've been playing through Medabots - Metabee Version and found that when fighting in the "Wilderness" area a peculiar graphical glitch occurs. Basically, anytime the fps dips below or rises above 60, the background sandstorm(?) effect becomes extremely pixelated. I'm playing with D3D 9 Linear filter enabled, have V-sync and Triple Buffering enabled, and pixel filers disabled. I have however tried out every combination of video or filter options I could think of in an effort to solve this with no success. I was able to figure out that the effect causing the issue is in layer BG 2 though, disabling it turns off the effect and pixelation issues don't persist elsewhere.

 

I can't capture an image of what the game should look like, because everytime I try to capture video or a screenshot the fps changes ever so slightly from 60 and thus becomes pixelated. Instead I have attached a picture of what the game looks like when it is pixelated as well as a zip file with both a battery save and save state. The save state is at the start of an encounter where the effect is used, and the battery save is in an area where if you run around a battle with the effect should happen. The effect should look like a smooth wave of sand or something near transparent moving up the screen, to see the pixelation simply press the turbo button or throttle the game to any speed besides 100% with no frame skipping.

 

Hope this gets solved soon because the game is nigh unplayable without turbo mode, and it's nigh unwatchable with this pixelation.

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[Squall Leonhart]

looks like another side effect of the gameboy's ability to blend between frames.

 

enable smart or motion blur under interframe blending.

[Trivial Man]

While enabling either blur option partially alleviates the problem, some graphical oddities still persist and some new ones are created.

 

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In the screenshot above for example the sandstorm effect is acting exactly as it should. This is by far the clearest screenshot I got while testing out these blur effects. This one was the motion blur effect if I remember correctly. However as you would expect from motion blur, the robot in the upper left corner and the medaparts button in the bottom center that were moving have some blur around them.

 

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More common were these screenshots that looked fine when I tried to take them, but came out only partially smooth looking and partially still very pixelated. The one on the left is the motion blur while the one on the right is the smart blur.

 

However when the battle was actually going on and the screen would watch the robots and their attacks, new issues would pop up.

 

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In these screenshots one of my robots is moving to shoot another. The pixelation that only appears in screenshots is there again covering part of the screen, but more importantly is that since the robots move around so much when they attack, they start to become an indistinct blur when motion blur is on. The one on the left is with motion blur on while the right is smart blur.

 

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For comparison, this is what it looks like when the robot uses the same attack without any blur or the offending bg 2 layer turned on.

 

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The screen moving to the right after an attack is made is also rendered somewhat sickening by the motion blurs. From left to right in these screenshots are: motion blur, smart blur (the worst offender), and no blur or bg 2 layer.

 

However, even ignoring these other issues, the primary complaint that in turbo mode the sandstorm becomes overly pixelated still persists. No matter what blending option was set, making the emulator run faster than a GBA could caused the sandstorm to obscure everything in pixels. Any other ideas on how this might be corrected?

[Trivial Man]

Well, it's been a couple weeks with no reply, so I assume there isn't an easy fix for this behavior. I guess I'm wondering now if there's any chance of this being fixed in a later release, or if I should look for another emulator to play this on.

[Squall Leonhart]

the problem is none of the previous devs have much interest in it anymore, i take and apply patches when provided though.

 

 

Currently we have someone not even affiliated with the project originally, taking a look at various read/write issues that causes the emulator to have freezes or potentially gfx issues.

[Squall Leonhart]

we might have just had a fix implemented for the corruption

 

it only fixes the C_Core of the emulator though, the windows builds uses ASM instead, so the fix has to be ported back to that.

[Trivial Man]

Hey, that's excellent news! I will be eagerly awaiting this fix. Thanks for figuring it out.

[Squall Leonhart]

give this a try

http://www.emucr.com/2013/03/visualboyadvance-m-svn-r1181.html

[Trivial Man]

Apologies for being so late to notice you uploaded that fix. I was waiting for an announcement on the front page or something. Anyways, I hate to say but whatever changes were made in this version still haven't fixed the issues this game is having. Without any motion blur enabled, sometimes framerates besides 60 cause the same pixelation. With either motion blur option enabled the turbo button still causes pixelation.

 

Here's another screenshot I took in turbo mode on the revision you posted here. Settings are motion blur on, render api set to Direct3D 9: nearest filter, v-sync triple buffer, and multi-threading, though I experimented with options and they yielded the same results.

 

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[Squall Leonhart]

Hi, can you provide CRC's for your rom dump.