x11: Move damage fetching code to X11Compositor

This is needed to make damage fetching specific to X11 surfaces.

src/composite.cpp

@@ -590,32 +590,19 @@ void Compositor::handleFrameRequested(RenderLoop *renderLoop)
 {
     // If outputs are disabled, we return to the event loop and
     // continue processing events until the outputs are enabled again
-    if (!kwinApp()->platform()->areOutputsEnabled()) {
-        return;
+    if (kwinApp()->platform()->areOutputsEnabled()) {
+        composite(renderLoop);
     }
+}
 
+void Compositor::composite(RenderLoop *renderLoop)
+{
     const int screenId = screenForRenderLoop(renderLoop);
 
     fTraceDuration("Paint (", screens()->name(screenId), ")");
 
     // Create a list of all windows in the stacking order
     QList<Toplevel *> windows = Workspace::self()->xStackingOrder();
-    QList<Toplevel *> damaged;
-
-    // Reset the damage state of each window and fetch the damage region
-    // without waiting for a reply
-    for (Toplevel *win : qAsConst(windows)) {
-        if (win->resetAndFetchDamage()) {
-            damaged << win;
-        }
-    }
-
-    if (damaged.count() > 0) {
-        m_scene->triggerFence();
-        if (auto c = kwinApp()->x11Connection()) {
-            xcb_flush(c);
-        }
-    }
 
     // Move elevated windows to the top of the stacking order
     for (EffectWindow *c : static_cast<EffectsHandlerImpl *>(effects)->elevatedWindows()) {
@@ -624,20 +611,6 @@ void Compositor::handleFrameRequested(RenderLoop *renderLoop)
         windows.append(t);
     }
 
-    // Get the replies
-    for (Toplevel *win : qAsConst(damaged)) {
-        // Discard the cached lanczos texture
-        if (win->effectWindow()) {
-            const QVariant texture = win->effectWindow()->data(LanczosCacheRole);
-            if (texture.isValid()) {
-                delete static_cast<GLTexture *>(texture.value<void*>());
-                win->effectWindow()->setData(LanczosCacheRole, QVariant());
-            }
-        }
-
-        win->getDamageRegionReply();
-    }
-
     // Skip windows that are not yet ready for being painted and if screen is locked skip windows
     // that are neither lockscreen nor inputmethod windows.
     //
@@ -818,13 +791,38 @@ void X11Compositor::start()
     }
     startupWithWorkspace();
 }
-void X11Compositor::handleFrameRequested(RenderLoop *renderLoop)
+
+void X11Compositor::composite(RenderLoop *renderLoop)
 {
     if (scene()->overlayWindow() && !isOverlayWindowVisible()) {
         // Return since nothing is visible.
         return;
     }
-    Compositor::handleFrameRequested(renderLoop);
+
+    QList<Toplevel *> windows = Workspace::self()->xStackingOrder();
+    QList<Toplevel *> damaged;
+
+    // Reset the damage state of each window and fetch the damage region
+    // without waiting for a reply
+    for (Toplevel *win : qAsConst(windows)) {
+        if (win->resetAndFetchDamage()) {
+            damaged << win;
+        }
+    }
+
+    if (damaged.count() > 0) {
+        scene()->triggerFence();
+        if (auto c = kwinApp()->x11Connection()) {
+            xcb_flush(c);
+        }
+    }
+
+    // Get the replies
+    for (Toplevel *window : qAsConst(damaged)) {
+        window->getDamageRegionReply();
+    }
+
+    Compositor::composite(renderLoop);
 }
 
 bool X11Compositor::checkForOverlayWindow(WId w) const

src/composite.h

@@ -115,9 +115,10 @@ protected:
     static Compositor *s_compositor;
 
 protected Q_SLOTS:
-    virtual void handleFrameRequested(RenderLoop *renderLoop);
+    virtual void composite(RenderLoop *renderLoop);
 
 private Q_SLOTS:
+    void handleFrameRequested(RenderLoop *renderLoop);
     void handleOutputEnabled(AbstractOutput *output);
     void handleOutputDisabled(AbstractOutput *output);
 
@@ -227,7 +228,7 @@ public:
 
 protected:
     void start() override;
-    void handleFrameRequested(RenderLoop *renderLoop) override;
+    void composite(RenderLoop *renderLoop) override;
 
 private:
     explicit X11Compositor(QObject *parent);

src/plugins/scenes/opengl/lanczosfilter.cpp

@@ -367,6 +367,10 @@ void LanczosFilter::performPaint(EffectWindowImpl* w, int mask, QRegion region,
             cache->unbind();
             w->setData(LanczosCacheRole, QVariant::fromValue(static_cast<void*>(cache)));
 
+            connect(effects, &EffectsHandler::windowDamaged,
+                    this, &LanczosFilter::safeDiscardCacheTexture,
+                    Qt::UniqueConnection);
+
             // Delete the offscreen surface after 5 seconds
             m_timer.start(5000, this);
             return;
@@ -380,6 +384,9 @@ void LanczosFilter::timerEvent(QTimerEvent *event)
     if (event->timerId() == m_timer.timerId()) {
         m_timer.stop();
 
+        disconnect(effects, &EffectsHandler::windowDamaged,
+                   this, &LanczosFilter::safeDiscardCacheTexture);
+
         m_scene->makeOpenGLContextCurrent();
 
         delete m_offscreenTarget;
@@ -404,6 +411,16 @@ void LanczosFilter::discardCacheTexture(EffectWindow *w)
     }
 }
 
+void LanczosFilter::safeDiscardCacheTexture(EffectWindow *w)
+{
+    QVariant cachedTextureVariant = w->data(LanczosCacheRole);
+    if (cachedTextureVariant.isValid()) {
+        m_scene->makeOpenGLContextCurrent();
+        delete static_cast< GLTexture*>(cachedTextureVariant.value<void*>());
+        w->setData(LanczosCacheRole, QVariant());
+    }
+}
+
 void LanczosFilter::setUniforms()
 {
     glUniform2fv(m_uOffsets, m_offsets.size(), (const GLfloat*)m_offsets.data());

src/plugins/scenes/opengl/lanczosfilter.h

@@ -45,6 +45,7 @@ private:
     void updateOffscreenSurfaces();
     void setUniforms();
     void discardCacheTexture(EffectWindow *w);
+    void safeDiscardCacheTexture(EffectWindow *w);
 
     void createKernel(float delta, int *kernelSize);
     void createOffsets(int count, float width, Qt::Orientation direction);