send list to EmitCachedFrameReady() rather than one rational at a time

Since EmitCachedFrameReady() makes a copy of the texture, we can economize a lot
by re-using the same copied texture for all the times rather than making a
separate copy for each time.

app/render/backend/opengl/openglbackend.cpp

@@ -141,7 +141,7 @@ void OpenGLBackend::DecompileInternal()
   shader_cache_.Clear();
 }
 
-void OpenGLBackend::EmitCachedFrameReady(const rational &time, const QVariant &value)
+void OpenGLBackend::EmitCachedFrameReady(const QList<rational> &times, const QVariant &value)
 {
   OpenGLTextureCache::ReferencePtr ref = value.value<OpenGLTextureCache::ReferencePtr>();
   OpenGLTexturePtr tex;
@@ -152,7 +152,9 @@ void OpenGLBackend::EmitCachedFrameReady(const rational &time, const QVariant &v
     tex = nullptr;
   }
 
-  emit CachedFrameReady(time, QVariant::fromValue(tex));
+  foreach (const rational& t, times) {
+    emit CachedFrameReady(t, QVariant::fromValue(tex));
+  }
 }
 
 OpenGLTexturePtr OpenGLBackend::CopyTexture(OpenGLTexturePtr input)

app/render/backend/opengl/openglbackend.h

@@ -28,7 +28,7 @@ protected:
 
   virtual void DecompileInternal() override;
 
-  virtual void EmitCachedFrameReady(const rational& time, const QVariant& value) override;
+  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value) override;
 
 private:
   OpenGLTexturePtr CopyTexture(OpenGLTexturePtr input);

app/render/backend/videorenderbackend.cpp

@@ -253,16 +253,21 @@ void VideoRenderBackend::ThreadCompletedFrame(NodeDependency path, QByteArray ha
   QVariant texture = table.Get(NodeParam::kTexture);
 
   // Check if this frame has changed once again, in which case we may not want to draw it (it'll look jittery to the user)
+  QList<rational> times_with_this_hash;
+
   if (last_time_requested_ == path.in() || export_mode_) {
-    EmitCachedFrameReady(path.in(), texture);
+    times_with_this_hash.append(path.in());
   }
 
   if (export_mode_) {
-    QList<rational> times_with_this_hash = frame_cache()->DeferredMapsWithHash(hash);
-    foreach (const rational& t, times_with_this_hash) {
-      EmitCachedFrameReady(t, texture);
-    }
-  } else {
+    times_with_this_hash.append(frame_cache()->DeferredMapsWithHash(hash));
+  }
+
+  if (!times_with_this_hash.isEmpty()) {
+    EmitCachedFrameReady(times_with_this_hash, texture);
+  }
+
+  if (!export_mode_) {
     if (texture.isNull()) {
       // No frame received, we set hash to an empty
       frame_cache()->RemoveHash(path.in(), hash);

app/render/backend/videorenderbackend.h

@@ -97,7 +97,7 @@ protected:
 
   virtual void ConnectWorkerToThis(RenderWorker* processor) override;
 
-  virtual void EmitCachedFrameReady(const rational& time, const QVariant& value) = 0;
+  virtual void EmitCachedFrameReady(const QList<rational> &times, const QVariant& value) = 0;
 
   bool export_mode_;