Delete lua + Use OpenGL for MPV

Deletes no longer needed Lua stuff -> also repair mpv because of mixed linking of lua (static and dynamic)

Also use OpenGL to embed mpv in the window (some problems on wayland because we have no wid...)

src/UI/DocumentViews/MpvContainer.cc

 #include "PreCompiledHeaders.hh"
 #include "UI/DocumentViews/MpvContainer.hh"
+#include <QtGui/QOpenGLContext>
+#include <QtCore/QMetaObject>
+#include <mpv/client.h>
+#include <mpv/render_gl.h>
 
 using namespace Vivy;
 using namespace std::string_literals;
 
+static void *
+get_proc_address(void *ctx, const char *name)
+{
+    QOpenGLContext *glctx = QOpenGLContext::currentContext();
+    if (!glctx)
+        return nullptr;
+    return reinterpret_cast<void *>(glctx->getProcAddress(QByteArray(name)));
+}
+
 void
 MpvContainer::mpvEventWakeUpCB(void *user) noexcept
 {
-    MpvContainer *container = reinterpret_cast<MpvContainer *>(user);
-    emit container->mpvEvent();
+    QMetaObject::invokeMethod(reinterpret_cast<MpvContainer *>(user), "mpvEvent",
+                              Qt::QueuedConnection);
 }
 
 MpvContainer::MpvContainer(QWidget *parent)
-    : QWidget(parent)
+    : QOpenGLWidget(parent)
     , mpv(mpv_create())
 {
     if (mpv == nullptr)
@@ -21,7 +34,7 @@ MpvContainer::MpvContainer(QWidget *parent)
     setAttribute(Qt::WA_DontCreateNativeAncestors);
     setAttribute(Qt::WA_NativeWindow);
 
-    logWarning() << "Don't init MPV by default, you should use the reload button!";
+    initializeMpv();
 }
 
 void
@@ -31,8 +44,6 @@ MpvContainer::initializeMpv()
         throw std::logic_error("MPV is already initialized!");
     isMpvAlreadyInitialized = true;
 
-    quint64 wid = winId();
-    mpv_set_option(mpv, "wid", MPV_FORMAT_INT64, &wid);
     mpv_set_option_string(mpv, "idle", "yes");
     mpv_set_option_string(mpv, "loop-file", "inf");
     mpv_set_option_string(mpv, "no-config", "yes");
@@ -56,14 +67,42 @@ MpvContainer::initializeMpv()
 }
 
 void
-MpvContainer::reCreateMpvContext()
+MpvContainer::initializeGL()
 {
-    closeMpv();
-    mpv = mpv_create();
-    if (mpv == nullptr)
-        throw std::runtime_error("Failed to create the MPV context");
-    initializeMpv();
-    loadFile(previousLoadedFile);
+    mpv_opengl_init_params gl_init_params;
+    memset(&gl_init_params, 0, sizeof(mpv_opengl_init_params));
+    gl_init_params.get_proc_address = get_proc_address;
+    mpv_render_param params[]{ { MPV_RENDER_PARAM_API_TYPE,
+                                 const_cast<char *>(MPV_RENDER_API_TYPE_OPENGL) },
+                               { MPV_RENDER_PARAM_OPENGL_INIT_PARAMS, &gl_init_params },
+                               { MPV_RENDER_PARAM_INVALID, nullptr } };
+
+    if (mpv_render_context_create(&mpv_gl, mpv, params) < 0) {
+        throw std::runtime_error("failed to initialize mpv GL context");
+    } else {
+        mpv_render_context_set_update_callback(mpv_gl, MpvContainer::onUpdate,
+                                               reinterpret_cast<void *>(this));
+    }
+}
+
+void
+MpvContainer::paintGL() noexcept
+{
+    mpv_opengl_fbo mpfbo{ static_cast<int>(defaultFramebufferObject()), width(), height(), 0 };
+    int flip_y{ 1 };
+
+    mpv_render_param params[] = { { MPV_RENDER_PARAM_OPENGL_FBO, &mpfbo },
+                                  { MPV_RENDER_PARAM_FLIP_Y, &flip_y },
+                                  { MPV_RENDER_PARAM_INVALID, nullptr } };
+    // See render_gl.h on what OpenGL environment mpv expects, and
+    // other API details.
+    mpv_render_context_render(mpv_gl, params);
+}
+
+void
+MpvContainer::onUpdate(void *ctx) noexcept
+{
+    QMetaObject::invokeMethod(reinterpret_cast<MpvContainer *>(ctx), "maybeUpdate");
 }
 
 void
@@ -82,24 +121,24 @@ MpvContainer::registerMpvDurationCallback(std::function<void(double)> callback)
     mpvDurationCallback = callback;
 }
 
-void
-MpvContainer::closeMpv() noexcept
+MpvContainer::~MpvContainer() noexcept
 {
+    makeCurrent();
+    logDebug() << "Closing the MPV context";
+    if (mpv_gl) {
+        mpv_render_context_free(mpv_gl);
+    }
     if (mpv) {
-        logDebug() << "Closing the MPV context";
         asyncCommand(AsyncCmdType::None, { "quit", nullptr });
+        mpv_wait_async_requests(mpv);
         registerMpvTimeCallback(nullptr);
         registerMpvDurationCallback(nullptr);
-        asyncCommand(AsyncCmdType::None, { "quit", nullptr });
-        mpv_wait_async_requests(mpv);
         mpv_destroy(mpv);
         mpv                     = nullptr; // Stop all other callbacks here
         isMpvAlreadyInitialized = false;   // De-init
     }
 }
 
-MpvContainer::~MpvContainer() noexcept { closeMpv(); }
-
 void
 MpvContainer::handleMpvEvent(const mpv_event *const event) noexcept
 {
@@ -117,7 +156,7 @@ MpvContainer::handleMpvEvent(const mpv_event *const event) noexcept
     };
 
     switch (event->event_id) {
-    case MPV_EVENT_SHUTDOWN: closeMpv(); break;
+    case MPV_EVENT_SHUTDOWN: logWarning() << "Ignore shutdown event for now..."; break;
 
     case MPV_EVENT_LOG_MESSAGE:
         msg     = reinterpret_cast<mpv_event_log_message *>(event->data);
@@ -233,6 +272,27 @@ MpvContainer::onMpvEvent() noexcept
     }
 }
 
+// Make Qt invoke mpv_render_context_render() to draw a new/updated video frame.
+void
+MpvContainer::maybeUpdate() noexcept
+{
+    // If the Qt window is not visible, Qt's update() will just skip rendering.
+    // This confuses mpv's render API, and may lead to small occasional
+    // freezes due to video rendering timing out.
+    // Handle this by manually redrawing.
+    // Note: Qt doesn't seem to provide a way to query whether update() will
+    //       be skipped, and the following code still fails when e.g. switching
+    //       to a different workspace with a reparenting window manager.
+    if (window()->isMinimized()) {
+        makeCurrent();
+        paintGL();
+        context()->swapBuffers(context()->surface());
+        doneCurrent();
+    } else {
+        update();
+    }
+}
+
 void
 MpvContainer::loadFile(const QString &filename) noexcept
 {
@@ -268,7 +328,7 @@ MpvContainer::printMpvError(int rc) const noexcept
     if (rc == MPV_ERROR_SUCCESS)
         return;
 
-    logError() << "MPV error:" << mpv_error_string(rc);
+    logError() << "MPV error: " << mpv_error_string(rc);
 }
 
 void
@@ -288,10 +348,6 @@ MpvContainer::mpvPause() noexcept
 void
 MpvContainer::mpvTogglePlayback() noexcept
 {
-    if (!isMpvAlreadyInitialized) {
-        reCreateMpvContext();
-    }
-
     logDebug() << "MPV: Toggling the playback";
     asyncCommand(AsyncCmdType::TogglePlayback, { "cycle", "pause", "up", nullptr });
 }