Need help cross compiling Love

[Tatwi]

Love is basically a set of custom Lua 5.1 bindings for SDL2, so in theory it should work OK. However, I honestly have no idea how to wrangle its Makefile into cross compiling it for the Miyoo CFW.

I have a Devuan 3.1 environment and I can build Love from source for x86_64 Linux with it. I also have a functional Bittboy toolchain configured. But I really don't know where to start with getting Love to cross compile, as it's not something I have experience with.

Any help here would be great, thanks!

[Rezzy-dev]

It's not simple -- it's quite technical, and requires patience and practice.

The first thing you need to do is point all the binary locations in your Makefile to where they are located in the toolchain. For me that is:

EXE_PREFIX = /opt/miyoo-toolchain/bin/arm-buildroot-linux-musleabi-
CC        = ${EXE_PREFIX}gcc
STRIP     = ${EXE_PREFIX}strip
LD = $(CC)

Then you need to check that there aren't any other hardcoded paths in the Makefile, and if there are and they are supposed to be pointing to the toolchain, change those too. If present, these usually occur in LIBS (software libraries/dependencies).

Finally, and this is where it get really tricky, if there are any missing CFLAGS or LDFLAGS for the software to run on this system, you'll need to figure what they are.

In most cases simply changing all the relevant binary/file paths to point to your toolchain will allow you to build, and if you're lucky, to run the software on the platform. After changing the paths, simply change into the source directory (where the Makefile is) and run make.

Different software were built and set up for/with different toolchains, which only further complicates things.

[Rezzy-dev]

Step by step instructions on how to set up the toolchain and build with it in the documentation, here:

https://github.com/TriForceX/MiyooCFW/wiki/Making-Games

[Tatwi]

Step 4 is no problem for a simple C program, but Love2D's makefile is enormous (and I'm unfamiliar with makefiles, beyond the basics).

Thank you for your insights though. :)

[Rezzy-dev]

I suggest you start with trying to build something simpler first.

[MiyanoOsu]

@Rezzy-dev i discover that Gmenu2x in cfw1.3.3 using Sdl2. Bc i check the library dir and found library of SDL2, i del it all and gmenu not working, just black screen after boot logo cfw. '-') so if source of Love writen with func that device support. May it work well.

[Rezzy-dev]

Hi @MiyanoOsu. :) To my best knowledge, and @TriForceX can confirm this, the Miyoo CFW does have an implementation of SDL2, but the problem is that SDL2 requires 3D hardware for much of its functioning, and Miyoo devices don't have a GPU (3D hardware). So the implementation is only a small subset of SDL2, actually -- which makes things quite complicated when it comes to porting/development.

Essentially, no hardware-related video features from SDL2 are supported (which make up the vast majority of SDL2), only a small subset of software-related video features. We can't support full SDL2 because Miyoo devices don't (yet) have 3D hardware, and (unlike SDL 1.2) SDL2 expects/requires it to work. Hope this helps to understand it. ^_^

I suspect that GMenuNX is not really using SDL2 in the full sense, only certain particular, limited 2D video and/or input and sound access functions from it.

[skrat]

Just here to say that "doesn't have GPU" doesn't mean it can't run SDL2. SDL2 does not care about which GL implementation is available. It only cares about it being available and in the API version that SDL2 needs (OpenGL 2.1, I think). And this can be provided by Mesa 3D which has actual software rendering (CPU) implementation of those APIs. Dunno if it can work, but in theory yes, probably with poor performance. I'd had to be tested how average Love game performs on those ARMv7s.

[jSTE0]

It seems to use the classic autoconf/automake build system. There are some instructions for cross-compilation here.
However, the bigger issue is the dependencies. SDL2 is not supported based on #280 (comment). It also appears to require "OpenGL 2.1+ / OpenGL ES 2+" which is definitely not supported as there is no 3D GPU.
An alternative is lutro which is part of RetroArch but only implements a subset of the love2d API. The core should build (with make platform=miyoo, a bug in .gitlab-ci.yml means it's not built on CI) but it is too slow on this platform, reaching around 30fps with audio skipping and the games being unplayable as a result.

[Tatwi]

That is some excellent info. Thank you.

[jSTE0]

You're welcome. The lutro core has since become available after one of the RetroArch maintainers decided to build it for Miyoo so you can at least try that without needing a toolchain.