libvpxhost

Hosts VPX message plugins in an application that is not VPX: the plugin bus (MsgPluginManager of the VPX plugin SDK), plugin discovery and loading, the settings answers, the script class registry and the logging API.

It is shared by the PPUC applications:

• ppuc: runs PinMAME, PUP, AltSound, B2S and DMD output as VPX plugins on a real machine.
• ColorizingDMD: the Serum colorization editor, for DMD output, PuP testing and video import.

Use

#include "vpxhost/PluginBus.h"

vpxhost::PluginBus bus({"MyApp", "My application", "Hosts VPX plugins"});
std::string error;
if (!bus.Initialize("/path/to/plugins", &error)) { /* error says why */ }
bus.SetSettingOverride("PUP", "PUPFolder", "/media/pupvideos");
bus.LoadPluginById("PUP");
// In the main loop:
bus.Process();

• One bus per process; it is not thread safe. Construct it on the thread that runs the main loop and keep it alive longer than everything that uses a plugin.
• The plugin folder holds one folder per plugin with its plugin.cfg and library, as VPX ships them.
• Settings: plugins get the host's override, or their own default. Every setting type of the SDK takes an override (string, folder, file, bool, int, float). Set overrides before the plugin is loaded.
• Logging: the second constructor argument receives the bus's own messages and every plugin's log lines; without it they go to stdout.

Build

The plugin SDK comes from a vpinball checkout, the one the application builds its plugins from:

cmake -S . -B build -DVPXHOST_VPINBALL_DIR=/path/to/vpinball
cmake --build build
ctest --test-dir build --output-on-failure

Only plugins/plugins/ and a few headers of third-party/include/ (mINI, plog, unordered_dense, stl.h) are used; see .github/workflows/libvpxhost.yml for a sparse checkout of just those. CI uses PPUC's vpinball fork at the commit ppuc pins (VPINBALL_SHA in ppuc/platforms/config.sh).

The result is a static library, vpxhost::vpxhost, which carries the SDK's include folders. As a subproject:

set(VPXHOST_VPINBALL_DIR "${VPINBALL_DIR}")
add_subdirectory(libvpxhost)
target_link_libraries(myapp PRIVATE vpxhost::vpxhost)

License

GPLv3 or later, as the VPX plugin SDK it compiles in.