[moltenvk] New Port

[Haeri]

This is a first attempt to port MoltenVK. This port is not 100% perfect and has TODOs but this is a first base-implementation. The port is based on the unfortunately closed #9575 PR.

• What does your PR fix? Fixes #
  This is a new port [New Port Request] MoltenVK #14698

• Which triplets are supported/not supported? Have you updated the CI baseline?
  Only osx is supported. CI is updated.

• Does your PR follow the maintainer guide?
  As much as possible. Unfortunately the dependencies of MoltenVK are handled with script files. It would require a big patch to adjust the dependencies to vcpkg.

[JackBoosY]

I'll help you to improve this PR later.

[JackBoosY]

Ops, the official build type is to use xcodebuild which we don’t support it now.
Let me find other solution.

[JackBoosY]

@Haeri I don't know xcode because I have never used it for development. Can you help me if I have any questions?

[Haeri]

@Haeri I don't know xcode because I have never used it for development. Can you help me if I have any questions?

Unfortunately me neither 😅 and I don't have access to a mac either at the moment. I am also not associated with the MoltenVK project in any way. I'm just trying to get it to work with my project. It is a bit unfortunate that they insist on using xcode instead of cmake or actual make (as you saw, their make file just calls xcode) but they argue, that this is justified, since this is an apple only project.

Also it is a bit surprising that the initial PR azure build failed as I have tested that version in my project with GitHub actions:
https://github.com/Haeri/ElementalDraw/runs/1468647387?check_suite_focus=true#step:3:7

PS: Any particular reason you removed the adjustments to ci.baseline.txt?

[JackBoosY]

@Haeri If we added Support keyword in manifest or CONTROL file, we don't need to add the same content on baseline.

[JackBoosY]

@Haeri Can you try this PR locally?

[Haeri]

@JackBoosY The main issue is that the vulkan dependency is only a check if the Vulkan SDK is installed and does not actually contain anything in it. That's why it fails when I run it on the GitHub runner:
https://github.com/Haeri/ElementalDraw/runs/1501915931?check_suite_focus=true#step:4:238

I assume that the Vulkan SDK is installed on the Azure pipeline, seeing that it didn't fail there.

[JackBoosY]

@Haeri No, Vulkan is skipped on our pipeline test.

[JackBoosY]

As @strega-nil said:

macOS does not support vulkan, at least natively; Khronos seems to have created a compatibility layer, maybe, but I'm not sure on that.
I'm not clear if this PR works.

[Haeri]

As @strega-nil said:

macOS does not support vulkan, at least natively; Khronos seems to have created a compatibility layer, maybe, but I'm not sure on that.
I'm not clear if this PR works.

@JackBoosY Not sure if this comment was directed towards me, but moltenvk is the compatibility layer @strega-nil is referring to.

[JackBoosY]

So if this PR works locally, then we can accept this without test on the pipeline.
However, I can't test it on my machine because I can't install vulkan.

[strega-nil]

@JackBoosY @Haeri isn't it the case that moltenvk provides vulkan given metal (installed by default on macOS)? You should be able to install it without any prerequisites, right?

[Haeri]

@strega-nil Yes MoltenVk is a portability implementation that allows Vulkan to run on Metal. It does have some prerequisites or dependencies on:

• Cereal
• Vulkan-Headers
• SPIRV-Cross
• glslang
• Vulkan-Tools
• VulkanSamples

All of them already have vcpkg ports except for Vulkan-Tools. I'm not sure if that is the cause, but I am unfortunately not able to successfully compile this current port @JackBoosY. I do a step, where I install the Vulkan SDK so the vulkan port does not abort for not being able to find VULKAN_SDK but still no luck:
https://github.com/Haeri/Mac-Runner/runs/1628063004#step:4:109

CMake Error at scripts/cmake/vcpkg_execute_build_process.cmake:145 (message):
    Command failed: "xcodebuild build -quiet -project MoltenVKPackaging.xcodeproj -scheme "MoltenVK Package (macOS only)" -configuration "Debug""
    Working Directory: /Users/runner/work/Mac-Runner/Mac-Runner/extern/vcpkg/buildtrees/moltenvk/x64-osx-dbg
    See logs for more information:

Unfortunately I am not able to find more log files to see what the problem is.

[JackBoosY]

@Haeri Can you manually run the command xcodebuild build -quiet -project MoltenVKPackaging.xcodeproj -scheme "MoltenVK Package (macOS only)" -configuration "Debug" in directory /Users/runner/work/Mac-Runner/Mac-Runner/extern/vcpkg/buildtrees/moltenvk/x64-osx-dbg ?

According to the official build docs, this command should work.

[Haeri]

@JackBoosY https://github.com/Haeri/Mac-Runner/runs/1628845754?check_suite_focus=true#step:5:56
Looks like it is having trouble finding the dependencies. I guess we will have to manually reimplement the stuff their fetchDependencies.sh is doing...

[JackBoosY]

@Haeri Yeah...

[PhoebeHui]

@Haeri, we prefer using CMake buildsystems, the OSX CI test machines doesn't support to executing the commands, and may not support in future, may be you can add a custom CMakeLists.txt instead?

[Haeri]

@PhoebeHui I completely understand and I also would have preferred for them to provide a proper cmake build system instead, but unfortunately, that's what they chose.
As I already mentioned, I have no affiliation at all with MoltenVK and to be honest, after spending one month trying to get their stuff to compile, I just can't be bothered to deal with it anymore. So instead I am using OpenGL as a stand-in backend for Vulkan on Apple platforms.
Feel free to close this PR at any time and maybe if someday they decide to switch to cmake, we can finalize this RP.

[PhoebeHui]

@Haeri, thanks for your response!