This app was mentioned in 14 comments, with an average of 1.64 upvotes
https://drive.google.com/file/d/0B59bV8HiqyB6bG5LMmZiU1l3TWM/view
There you go. The only shaders available for My Boy are this and the one from the play store.
Only real difference is the one I linked from Google Drive has two additional shaders. Those shaders were already there but never made the play store build. I was able to grab the source and compile it a long time back before Google Code went down.
Both of these also work with My Oldboy.
Since you're using My Boy:
ZeldaMinishCap on gba. IMO
Edit:
FinalFantasyTactics on gba and nds. SummonNightSwordCraftStory on gba. PhoenixWright on gba and nds. Megaman gba and nds. Disgaea on nds. And many more
With hq4x for MyBoy! (gba) [ https://play.google.com/store/apps/details?id=com.fastemulator.shaderpack ] and 5XBRVeryHighConfig for DraStic (NDS) [ https://www.reddit.com/r/EmulationOnAndroid/comments/axacm9/this_is_pretty_damn_cool_drastic_was_worth_it/ehza8v9?utm_source=reddit-android ].
Use This app To add new shaders to your my boy which will make the graphics Look 10x more better, I use quilez but you can experiment around because there are tons of them
In that case, My Boy! is actually a good choice for GBA emulation in your case. The othe GBA emulators available (GBA.emu, Retroarch's VBA-M and mGBA cores) aren't going to run full speed on that device, can confirm from personal experience with the chipset.
Don't forget to get the shader pack as well. (Note, that's my own compiled version with some extra shaders. The original of that shader pack is on the play store).
Could be a number of reasons, but honestly RetroArch isn't for everyone anyways. I still use My Boy! majority of the time just because I too get tired of troubleshooting problems.
I mostly only use RetroArch whenever I want to load up the emulators that are good for accuracy (mGBA, bsnes, Nestopia, etc.)
EDIT: to name a few My Boy! also supports Shaders, extra settings over video and audio controls, and lets you create app shortcuts on your home screen to instantly launch games (imo the best feature)
No prob. If you're going to use My Boy, don't forget to grab the shader pack for it.
There's a build on the Play Store, but I have a build I compiled from the source before Google code got archived, it's got a few additional shaders (2xbr, 4xbr, and quilez) that aren't in the Play Store build.
If you don't want to sideload an unknown source I understand. The play store build is here. If you want the updated build you can get it here (google drive upload link).
If you're emulating on Android, the shader pack for My Boy! includes scanlines as one of its filters.
I compiled an updated build myself with some shaders that didn't make the play store version (2/4xbr, quilez) as well. That can be downloaded here if you don't mind sideloading.
Which ipega controller are you using and how is it connected? The best way is to connect as an Android HID game controller. To do that, hold 'x' and then press the home button to sync in that mode. It may help to unpair your controller and re-pair it this way (even if you originally paired it this way).
Also, try My Boy! Free to see if you still get the slowdowns there. It was made for ARM from the ground up, not ported from PC. It's hands down the best GBA emulator for Android, and blows VBA-M (which I believe GBA.emu is based on) out of the water in terms of emulation speed.
Also, My Boy! (and My Oldboy for GB/GBC emulation) has a shader pack available. You can get it on the play store here, or if you don't mind sideloading apps, I compiled it with three additional shaders, link here. (Note - I'm not the creator, I just compiled the creator's source since the play store version was out of date).
Yeah, I feel you. I did a similar build a week or two ago to update the Emulation Shaders pack for the My Boy! emulator.
That one was worth doing though, as the play store version is out of date and compiling my own got me the additions of the Quilez and 2x/4xbr shaders, plus the ability to add my own in the future (just gotta add GLSL shader pack to the project in its own folder and add the name of the shader file to the Array and the ArrayList in two files I think, then recompile and sideload again). It was a lot easier too, that one I was able to just pull the project and compile the APK in Android Studio.
Mostly I just wanted the quilez shader, as none of the built-ins looked good, and I can't stand the "smooth" look of H#qx.
I don't have it anymore but the original shader pack is on Google Play here
https://play.google.com/store/apps/details?id=com.fastemulator.shaderpack (I hope you now how to set shader)
I thought My Boy! was actually pretty good display-wise, but my only experience with native GBA is the GB Micro. I use the Emulator Shaders app (which pairs with My Boy!, link is here) and use an LCD overlay to make it look more like the original (although that will definitely not make it look sharper). But something like the hq2x resolution or another shader might give you what you want. There's is an unofficial update to this shader app that can be found here but I've not tried it, but apparently it offers some more filters that might fit the bill for you. I just found this video that shows you what some of them look like if you want to take a look - https://www.youtube.com/watch?v=_VkBhhuINDY - turn the sound down though cos the music's awful! As a side note, I think you can only use shaders on the full (paid) version of My Boy!, so if you're rocking the free version you might not be able to use them.
Other than that, you could try GBA.EMU - I used to use that, and it offers a few different screen sizes/filters, there's also a free version available but you can't get it on the Play Store (link is here). TBH any GBA emulator will probably look a little rough as you're effectively blowing up a 240 × 160 3:2 resolution, but filters/shaders should help a little. I've also heard good things about Pizzaboy and John GBA - there's free/lite versions if you wanted to give them a demo... last one I can think of is Classicboy (which is multi-system emulator) but that hasn't been updated for years, probably wouldn't recommend it unless you want an all-in-one solution.
i honestly cant stand emulators in portrait imo, but you can add an lcd filter to myboy with this app, and setting it to LCD3x in the video settings, under glsl shader. the same can be done in myoldboy