MSVC support

[lukas-w]

Creating this issue to keep track of tasks required to make LMMS build compatible with MSVC (related to #3492). I'll try to keep this list up to date:

• Fix LMMS core code & CMake: Done via MSVC fixes #4000
• Fix plugins that fail building:
  • LadspaEffect: done via Enable LADSPA plugins on MSVC #6973
  • Monstro: done via b7c0997
  • Organic: done per ac65fb9
  • ReverbSC: done via 57c85f4
  • SID: done via a0ace86
  • VST: done via Fix MSVC VST compilation #4421 and f245d74
  • Vibed: done via adcc009
  • Xpressive: done via 1c5e374
  • ZynAddSubFX: done via Support ZynAddSubFx with MSVC #6561
  • Mallets: done via Support Sf2 Player, Mallets, PortAudio, and Lame with MSVC #6507
  • SF2 player: done via Support Sf2 Player, Mallets, PortAudio, and Lame with MSVC #6507
  • Gig player: in progress at Add MSVC support for GigPlayer (rework) #7162
• Add continuous integration, options: (done via Add MSVC Appveyor CI #4439):
  • AppVeyor
  • Visual Studio Team Services

Because Windows provides no package management that we can use for grabbing dependencies, we'll need to find another way of making the overall build process easier.
VCPKG is gaining popularity quickly and already includes almost all of the dependencies we need. The only issue with it is that it always compiles from source, so it's not a good candidate for huge dependencies like Qt. It can be used together with the official Qt binaries though.

Edit: Maybe GitHub's "Project" feature is better for this?

[tresf]

I've been putting some time into investigating scoop.sh for dependencies. So far we have a working example of libsndfile, fftw and I'm working with upstream on libsamplerate.

Scoop's strategy is to use working-binaries of projects and just fetch them from whichever HTTP or FTP mirror they already offer, but place them in the user's home directory (e.g. ~/scoop/apps/libsndfile/current/).

We've successfully made cmake and pkg-config locate these libraries:

• cmake: We're adding the relevant library folder to environmental variable CMAKE_PREFIX_PATH
• pkgconfig: We're adding the relevant library folder to environmental variable PKG_CONFIG_PATH

I propose scoop.sh as an alternative to Hunter, as the syntax is similar to apt-get or homebrew.

# mockup
scoop install libsndfile fftw libsamplerate

The disadvantage of this approach over Hunter is the majority of the dependency mirrors need to be created and maintained whereas Hunter has the ability to build directly from source.

[lukas-w]

I think Vcpkg is the best candidate at the moment. I updated the issue accordingly. I'll change the wiki instructions to vcpkg as well if you don't mind, @tresf.

[tresf]

I'll change the wiki instructions to vcpkg as well if you don't mind, @tresf.

If it works, 👍. Does vcpkg have any pre-built binaries, or is it all downloaded and compiled? vcpkg is going to be less reliant on us maintaining packages all the time, but will likely add much more time to the compilation process.

[lukas-w]

Does vcpkg have any pre-built binaries, or is it all downloaded and compiled?

Unfortunately, no. Mixing official Qt binaries together with libraries provided by vcpkg appears to work fine though.

[Cangle50]

To make it easer to follow is it possible to update LMMS compiling instructions for Windows MSVC to better show how we should do it by today’s standards.

My concern is that my Security Suite when navigating to the msys2 download site to install the Mingw-w64 compiler (that the QT5 Qt Creator IDE doesn’t appear to provide) is blocking me.

Some questions I have are.

Is msys2 still safe to use?

Is Qt 5.12.0 the best version to use right now, there appears to be a Drag and Drop issue with QT5?

Is it possible that the compatibility for Windows MSVC has gotten better, so that statements like "Warning, MSVC building is still experimental? Use with caution. Most plugins aren't available when compiling with MSVC" are no longer necessary? It feels as if we are encouraged not to use Windows MSVC for whatever reasons imho.

I am trying to teach myself how to write code and would like to use LMMS to study and learn from I realize that I have a long way to go.

Things I have done.

1. Installed Visual Studio 2017 Community.

2. Installed Qt Open Source version 5.12.0 64/32bit with Qt Creator.

3. Installed CMake.

4. Installed Git.

5. Installed Vcpkg. I am in the process of installing fftw3
   libsamplerate libsndfile sdl2

I am working on a windows 10 64bit pc.

Sorry to ramble on I am writing this for myself and anyone else who maybe having problems following along.

[tresf]

My concern is that my Security Suite when navigating to the msys2 download site to install the Mingw-w64 compiler (that the QT5 Qt Creator IDE doesn’t appear to provide) is blocking me.

I strongly recommend that you contact Spectrum and challenge this claim. Msys2 is a great product.

Is msys2 still safe to use?

Unless proven otherwise, yes. Is it useful for compiling LMMS? Mostly. The build toolchain is very volatile so it's not recommended. MSVC would be a much "pure" build system at this point. Our msys2 toolchain has tools that are cloned from the Linux cross-compiler, but it's what we've been using historically. If you have success using MSVC, please use that instead and help us improve our documentation.

Is it possible that the compatibility for Windows MSVC has gotten better, so that statements like "Warning, MSVC building is still experimental? Use with caution. Most plugins aren't available when compiling with MSVC" are no longer necessary?

It's still experimental, that part is true but the warning doesn't need to be as harsh. The plugin support is getting better, so I've clarified that only some plugins aren't available with MSVC.

I am trying to teach myself how to write code and would like to use LMMS to study and learn from I realize that I have a long way to go.

Please continue to provide your feedback with the build process. For assistance, please use #techtalk channel on discord and we'll be happy to offer any help we can offer. You're welcome to chime in on this channel with wiki inaccuracies and/or fixes.

https://discordapp.com/invite/PruNxpG

[PhysSong]

I just noticed SF2 player and GIG player are still MSVC incompatible due to VLAs.

lmms/plugins/sf2_player/sf2_player.cpp

Lines 634 to 635 in 29c2101

	fluid_voice_t * voices[poly];
	unsigned int id[poly];

lmms/plugins/GigPlayer/GigPlayer.cpp

Line 451 in 29c2101

sampleFrame sampleData[samples];

lmms/plugins/GigPlayer/GigPlayer.cpp

Line 468 in 29c2101

sampleFrame convertBuf[frames];

lmms/plugins/GigPlayer/GigPlayer.cpp

Line 540 in 29c2101

int8_t buffer[allocationsize];

[Rossmaxx]

Here to tell you about #6758

[Rossmaxx]

Bump the checklist pls, and also the gig pr has changed to #7162