Refactor texture viewer thumbnails to not use swapchains

* There seems to be a significant slowdown when using real swapchains, both for
  creation and display. Since thumbnails don't update often (only on event
  change, or if the panel is resized which is not a regular occurence)
  counterintuitively it's better to render and readback the image offscreen and
  re-upload it on the CPU.

qrenderdoc/Widgets/ResourcePreview.cpp

@@ -35,6 +35,29 @@ ResourcePreview::ResourcePreview(ICaptureContext &c, IReplayOutput *output, QWid
   ui->thumbnail->SetContext(c);
   ui->thumbnail->SetOutput(output);
 
+  Initialise();
+}
+
+ResourcePreview::ResourcePreview(bool, QWidget *parent)
+    : QFrame(parent), ui(new Ui::ResourcePreview)
+{
+  ui->setupUi(this);
+
+  delete ui->thumbnail;
+  ui->thumbnail = NULL;
+  m_ManualThumbnail = new RDLabel();
+  m_ManualThumbnail->setGeometry(QRect(0, 0, 16, 16));
+  m_ManualThumbnail->setScaledContents(true);
+  m_ManualThumbnail->setSizePolicy(
+      QSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding));
+
+  ui->gridLayout->addWidget(m_ManualThumbnail, 0, 0, 1, 2);
+
+  Initialise();
+}
+
+void ResourcePreview::Initialise()
+{
   setBackgroundRole(QPalette::Background);
   setForegroundRole(QPalette::Foreground);
 
@@ -57,12 +80,19 @@ ResourcePreview::ResourcePreview(ICaptureContext &c, IReplayOutput *output, QWid
   ui->descriptionLabel->setForegroundRole(QPalette::Foreground);
   ui->descriptionLabel->setFont(Formatter::PreferredFont());
 
-  QObject::connect(ui->thumbnail, &CustomPaintWidget::clicked, this, &ResourcePreview::clickEvent);
+  if(ui->thumbnail)
+    QObject::connect(ui->thumbnail, &CustomPaintWidget::clicked, this, &ResourcePreview::clickEvent);
+  else if(m_ManualThumbnail)
+    QObject::connect(m_ManualThumbnail, &RDLabel::clicked, this, &ResourcePreview::clickEvent);
   QObject::connect(ui->slotLabel, &RDLabel::clicked, this, &ResourcePreview::clickEvent);
   QObject::connect(ui->descriptionLabel, &RDLabel::clicked, this, &ResourcePreview::clickEvent);
 
-  QObject::connect(ui->thumbnail, &CustomPaintWidget::doubleClicked, this,
-                   &ResourcePreview::doubleClickEvent);
+  if(ui->thumbnail)
+    QObject::connect(ui->thumbnail, &CustomPaintWidget::doubleClicked, this,
+                     &ResourcePreview::doubleClickEvent);
+  else if(m_ManualThumbnail)
+    QObject::connect(m_ManualThumbnail, &RDLabel::doubleClicked, this,
+                     &ResourcePreview::doubleClickEvent);
   QObject::connect(ui->slotLabel, &RDLabel::doubleClicked, this, &ResourcePreview::doubleClickEvent);
   QObject::connect(ui->descriptionLabel, &RDLabel::doubleClicked, this,
                    &ResourcePreview::doubleClickEvent);
@@ -110,5 +140,33 @@ void ResourcePreview::setSelected(bool sel)
 
 WindowingData ResourcePreview::GetWidgetWindowingData()
 {
-  return ui->thumbnail->GetWidgetWindowingData();
+  if(ui->thumbnail)
+    return ui->thumbnail->GetWidgetWindowingData();
+  return {};
+}
+
+QSize ResourcePreview::GetThumbSize()
+{
+  if(ui->thumbnail)
+    return ui->thumbnail->size();
+
+  if(m_ManualThumbnail)
+    return m_ManualThumbnail->size();
+
+  return {};
+}
+
+void ResourcePreview::UpdateThumb(QSize s, const bytebuf &imgData)
+{
+  if(!m_ManualThumbnail)
+    return;
+
+  QImage thumb(imgData.data(), s.width(), s.height(), s.width() * 3, QImage::Format_RGB888);
+  m_ManualThumbnail->setPixmap(QPixmap::fromImage(thumb));
+}
+
+void ResourcePreview::resizeEvent(QResizeEvent *e)
+{
+  emit resized(this);
+  QFrame::resizeEvent(e);
 }

qrenderdoc/Widgets/ResourcePreview.h

@@ -34,6 +34,7 @@ class ResourcePreview;
 
 struct IReplayOutput;
 struct ICaptureContext;
+class RDLabel;
 
 class ResourcePreview : public QFrame
 {
@@ -41,11 +42,17 @@ class ResourcePreview : public QFrame
 
 public:
   explicit ResourcePreview(ICaptureContext &c, IReplayOutput *output, QWidget *parent = 0);
+  // create a manually rendered preview
+  explicit ResourcePreview(bool, QWidget *parent = 0);
+
+  void Initialise();
+
   ~ResourcePreview();
 
 signals:
   void clicked(QMouseEvent *e);
   void doubleClicked(QMouseEvent *e);
+  void resized(ResourcePreview *prev);
 
 public:
   void setSlotName(const QString &n);
@@ -55,6 +62,8 @@ public:
   void doubleClickEvent(QMouseEvent *e);
 
   WindowingData GetWidgetWindowingData();
+  QSize GetThumbSize();
+  void UpdateThumb(QSize s, const bytebuf &imgData);
 
   void setActive(bool b)
   {
@@ -68,8 +77,12 @@ public:
   void setSelected(bool sel);
 
 private:
+  virtual void resizeEvent(QResizeEvent *event);
+
   Ui::ResourcePreview *ui;
 
+  RDLabel *m_ManualThumbnail = NULL;
+
   bool m_Active;
   bool m_Selected = false;
 };

qrenderdoc/Windows/TextureViewer.cpp

@@ -1981,10 +1981,11 @@ void TextureViewer::textureTab_Closing(int index)
 
 ResourcePreview *TextureViewer::UI_CreateThumbnail(ThumbnailStrip *strip)
 {
-  ResourcePreview *prev = new ResourcePreview(m_Ctx, m_Output);
+  ResourcePreview *prev = new ResourcePreview(true);
 
   QObject::connect(prev, &ResourcePreview::clicked, this, &TextureViewer::thumb_clicked);
   QObject::connect(prev, &ResourcePreview::doubleClicked, this, &TextureViewer::thumb_doubleClicked);
+  QObject::connect(prev, &ResourcePreview::resized, this, &TextureViewer::UI_PreviewResized);
 
   prev->setActive(false);
   strip->addThumb(prev);
@@ -2366,6 +2367,7 @@ void TextureViewer::InitResourcePreview(ResourcePreview *prev, BoundResource res
                                         Following &follow, const QString &bindName,
                                         const QString &slotName)
 {
+  Subresource sub = {0, 0, ~0U};
   if(res.resourceId != ResourceId() || force)
   {
     QString fullname = bindName;
@@ -2380,8 +2382,6 @@ void TextureViewer::InitResourcePreview(ResourcePreview *prev, BoundResource res
 
     prev->setResourceName(fullname);
 
-    WindowingData winData = prev->GetWidgetWindowingData();
-
     prev->setProperty("f", QVariant::fromValue(follow));
     prev->setSlotName(slotName);
     prev->setActive(true);
@@ -2389,20 +2389,15 @@ void TextureViewer::InitResourcePreview(ResourcePreview *prev, BoundResource res
 
     if(m_Ctx.GetTexture(res.resourceId))
     {
-      m_Ctx.Replay().AsyncInvoke([this, winData, res](IReplayController *) {
-        Subresource sub = {0, 0, ~0U};
-        if(res.firstMip >= 0)
-          sub.mip = res.firstMip;
-        if(res.firstSlice >= 0)
-          sub.slice = res.firstSlice;
-        m_Output->AddThumbnail(winData, res.resourceId, sub, res.typeCast);
-      });
+      if(res.firstMip >= 0)
+        sub.mip = res.firstMip;
+      if(res.firstSlice >= 0)
+        sub.slice = res.firstSlice;
     }
     else
     {
-      m_Ctx.Replay().AsyncInvoke([this, winData](IReplayController *) {
-        m_Output->AddThumbnail(winData, ResourceId(), {0, 0, ~0U}, CompType::Typeless);
-      });
+      res.resourceId = ResourceId();
+      res.typeCast = CompType::Typeless;
     }
   }
   else if(m_Following == follow)
@@ -2411,17 +2406,48 @@ void TextureViewer::InitResourcePreview(ResourcePreview *prev, BoundResource res
     prev->setActive(true);
     prev->setSelected(true);
 
-    WindowingData winData = prev->GetWidgetWindowingData();
-    m_Ctx.Replay().AsyncInvoke([this, winData](IReplayController *) {
-      m_Output->AddThumbnail(winData, ResourceId(), {0, 0, ~0U}, CompType::Typeless);
-    });
+    res.resourceId = ResourceId();
+    res.typeCast = CompType::Typeless;
   }
   else
   {
     prev->setResourceName(QString());
     prev->setActive(false);
     prev->setSelected(false);
+
+    return;
   }
+
+  prev->setProperty("id", QVariant::fromValue(res.resourceId));
+  prev->setProperty("mip", sub.mip);
+  prev->setProperty("slice", sub.slice);
+  prev->setProperty("cast", uint32_t(res.typeCast));
+
+  GUIInvoke::call(this, [this, prev] { UI_PreviewResized(prev); });
+}
+
+void TextureViewer::UI_PreviewResized(ResourcePreview *prev)
+{
+  QSize s = prev->GetThumbSize();
+
+  ResourceId id = prev->property("id").value<ResourceId>();
+  Subresource sub = {0, 0, ~0U};
+  sub.mip = prev->property("mip").toUInt();
+  sub.slice = prev->property("slice").toUInt();
+  CompType typeCast = (CompType)prev->property("cast").toUInt();
+
+  m_Ctx.Replay().AsyncInvoke(lit("preview%1").arg((qulonglong)(void *)prev),
+                             [this, prev, s, sub, id, typeCast](IReplayController *) {
+                               bytebuf data =
+                                   m_Output->DrawThumbnail(s.width(), s.height(), id, sub, typeCast);
+                               // new and swap to move the data into the lambda
+                               bytebuf *copy = new bytebuf;
+                               copy->swap(data);
+                               GUIInvoke::call(this, [prev, s, copy]() {
+                                 prev->UpdateThumb(s, *copy);
+                                 delete copy;
+                               });
+                             });
 }
 
 void TextureViewer::InitStageResourcePreviews(ShaderStage stage,

qrenderdoc/Windows/TextureViewer.h

@@ -275,6 +275,8 @@ private:
                                  rdcarray<BoundResourceArray> &ResList, ThumbnailStrip *prevs,
                                  int &prevIndex, bool copy, bool rw);
 
+  void UI_PreviewResized(ResourcePreview *prev);
+
   void AddResourceUsageEntry(QMenu &menu, uint32_t start, uint32_t end, ResourceUsage usage);
   void OpenResourceContextMenu(ResourceId id, bool input, const rdcarray<EventUsage> &usage);