WIP: Meson build

[BastiaanOlij]

Working together with @thaytan to move over to using meson to build so we can automatically pull in the latest openhmd or direct to specific branches of this.

[BastiaanOlij]

Currently stuck on

The Meson build system
Version: 0.54.0
Source dir: D:\Development\xr_plugins\godot_openhmd
Build dir: D:\Development\xr_plugins\godot_openhmd\builddir
Build type: native build
Project name: openhmd_godot
Project version: 0.1.0
C compiler for the host machine: cl (msvc 19.25.28611)
C linker for the host machine: link link 14.25.28611.0
Host machine cpu family: x86_64
Host machine cpu: x86_64

|Executing subproject OpenHMD method meson
|
|Project name: openhmd
|Project version: 0.3.0
|C compiler for the host machine: cl (msvc 19.25.28611)
|C linker for the host machine: link link 14.25.28611.0
|Library m found: NO
|Did not find pkg-config by name 'pkg-config'
|Found Pkg-config: NO
|Found CMake: C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.EXE (3.16.19112601-MSVC_2)
|Run-time dependency hidapi found: NO (tried pkgconfig and cmake)
|subprojects\OpenHMD\meson.build:31: WARNING: Dependency hidapi not found but it is available in a sub-subproject.
|To use it in the current project, promote it by going in the project source
|root and issuing the following command:
|meson wrap promote subprojects\OpenHMD\subprojects\hidapi.wrap

subprojects\OpenHMD\meson.build:31:1: ERROR: Subproject directory not found and hidapi.wrap file not found

A full log can be found at D:\Development\xr_plugins\godot_openhmd\builddir\meson-logs\meson-log.txt

hidapi.wrap is there, not sure why it can't run it, possibly because I need to install pkgconfig first?

[BastiaanOlij]

Ok, the answer was in there:
meson wrap promote subprojects\OpenHMD\subprojects\hidapi.wrap

This copies the hidapi.wrap into our subprojects folder and allows us to build it..

Now I need to find out how to tell it to copy the final dll into the right place

[BastiaanOlij]

Ok, it now works though you need to copy all the files in place and I'm not sure I like the -0 suffix the openhmd and godot_openhmd dlls get. I get why, though its weird hidapi doesn't get the suffix.

I'll be improving the demo a little more and then I will likely merge this.

[thaytan]

The -0 suffix on built dlls comes from having a version: library_version line in the meson library() declaration - it's to allow parallel installation of versions with different ABI. Could be avoided with a platform check in the relevant meson builds, like:

library_kwargs = {}
if host_machine.system() == 'windows'
library_kwargs = {'soversion': false}
endif
...
library(..., kwargs: library_kwargs)

[thaytan]

For copying the build artifacts into the uninstalled directories for use, one can use a meson custom_target() that runs a script, and you can assign a ninja target name to it with alias_target(). So you can tell people to do ninja prepare or something which will copy the artifacts. However, if you need to copy from multiple builddirs, it's probably best to have a wrapper script that calls meson multiple times for each target platform in separate builddirs and then consolidates it into one.