[Tutorial] Installing MVEM (Milton-Bradley Microvision emulation) on RPi 3

rkoster

Oh, and FYI, GIMP can in fact do BMP with alpha. It needs to be set up as a channel called Alpha, and saved in one of the BMP formats that allows it. These ones are using R8.

All these images should have it, but by default, the alpha channel is usually not visible. In Photoshop at least you have to open the image, go to Channels, make it visible, then save.

NowArrivingHere

@rkoster

Okay, I just tried your reduced snaps. It still isn't loading properly. If this is caused by the combined size of all the images being loaded together, it might be a good idea to downsize the actual screen overlays. These are 1.4MB each and are now the largest images loaded when a game is booted, as the snaps are 774KB apiece, the keyhints.bmp is 774KB, and the knob.bmp is 255KB

Also, I'm going to add a screenshot of one of your images loaded into GIMP. I'm not an expert in GIMP, but I am looking at the Channels panel, and I only see a Red, Green, and Blue. I know the images must have an alpha channel due to the transparency, but my GIMP is not recognizing it as such and certaintly not exporting it as such. It must be some sort of import error on my end.

rkoster

I will reduce everything to 512 then. Some video chips automatically go to powers of 2 for texture sizes, this should ensure that it stays at 512x512. These others would have gone to 1024x1024. I'll do both overlays and snaps. Give me about half an hour :)

rkoster

OK, try snap512.zip. I took extra time and fixed the rounded corners which weren't alpha before (hard to see, but it was bugging me!).

If this doesn't do it, I really don't know what else to suggest. 3 512x512 textures plus the knob at 256 is not very much, and stuff will definitely get blurry if I have to go to 256 for the larger items.

NowArrivingHere

@rkoster

Okay, here is the situation. It still doesn't work, but don't bother reducing the image size anymore. It will not help. I recommend you just go with either the snap512.zip or snapreduced.zip for any Raspberry Pi distributions. The original ~14MB _snap.bmp caused a different issue on the Raspberry Pi where even standalone MVEM would not load the images. As far as the issue with having to quit emulation station, run MVEM standalone, and reload emulation station to have the images show up in RetroPie, I think I have conclusively shown that we cannot fix it. It is either a bug in SDL or a bug in how EmulationStation/RetroPie handles SDL-based external emulators.

I decided to run a test by replacing the Baseball.bmp, Baseball_snap.bmp, knob.bmp, and keyhints.bmp with solid color bitmap images of the same dimensions as the snap512.zip .bmp files. Here are the file size comparisons

Baseball.bmp
Old: 1,011 KB
New: 129 KB

Baseball_snap.bmp
Old: 393 KB
New: 51 KB

knob.bmp
Old: 255 KB
New: 32 KB

keyhints.bmp
Old: 393 KB
New: 51 KB

It had the same problem as before with needing to quit ES, run MVEM, and reload ES to make everything show up

And just to be extra thorough, I took my solid color bitmaps and halved their dimensions to the 256 dimensions

Baseball.bmp
Old: 1,011 KB
New: 33 KB

Baseball_snap.bmp
Old: 393 KB
New: 14 KB

knob.bmp
Old: 255 KB
New: 9 KB

keyhints.bmp
Old: 393 KB
New: 14 KB

It had the same problem again.

So I think we can safely say that this is not a problem that we can fix. After all, when running MVEM outside of RetroPie, the problem does not occur. It might not even be an issue to people using other front-ends. Having to quit ES, run MVEM once separately, and reload ES to allow MVEM to load properly inside RetroPie is inconvenient, but it isn't the end of the world. I am interested to hear from other users who install this emulator on their RetroPie setups as to whether this happens to them as well. It may be that there is some sort of missing SDL setting that is applied to emulators featured in the RetroPie script that MVEM Build 15 either can't use or isn't using.

Thank you for working with me on this for so long. I still consider Build 15 an improvement over running Build 14 in RetroPie, in spite of this issue. Hopefully, at some point, the image loading issue can be resolved, but that may require MVEM Build 15 being added to the official RetroPie script.

rkoster

Thanks for running the experiments!

I'll see if I can make some time to make a nicer distribution with the Makefile set up for Pi, with just the binary, just the assets, etc, in separate zips, that way we can link it here.