Allow clicking 'next draw' from the frame start marker at EID 0

qrenderdoc/Code/CaptureContext.cpp

@@ -139,11 +139,10 @@ void CaptureContext::LoadLogfile(const QString &logFile, const QString &origFile
     QVector<ILogViewer *> logviewers(m_LogViewers);
 
     // make sure we're on a consistent event before invoking log viewer forms
-    const DrawcallDescription *draw = &m_Drawcalls.back();
-    while(!draw->children.empty())
-      draw = &draw->children.back();
-
-    SetEventID(logviewers, draw->eventID, true);
+    if(m_LastDrawcall)
+      SetEventID(logviewers, m_LastDrawcall->eventID, true);
+    else if(!m_Drawcalls.empty())
+      SetEventID(logviewers, m_Drawcalls.back().eventID, true);
 
     GUIInvoke::blockcall([&logviewers]() {
       // notify all the registers log viewers that a log has been loaded
@@ -205,6 +204,8 @@ void CaptureContext::LoadLogfileThreaded(const QString &logFile, const QString &
 
   m_EventID = 0;
 
+  m_FirstDrawcall = m_LastDrawcall = NULL;
+
   // fetch initial data like drawcalls, textures and buffers
   m_Renderer.BlockInvoke([this](IReplayController *r) {
     m_FrameInfo = r->GetFrameInfo();
@@ -217,6 +218,14 @@ void CaptureContext::LoadLogfileThreaded(const QString &logFile, const QString &
 
     AddFakeProfileMarkers();
 
+    m_FirstDrawcall = &m_Drawcalls[0];
+    while(!m_FirstDrawcall->children.empty())
+      m_FirstDrawcall = &m_FirstDrawcall->children[0];
+
+    m_LastDrawcall = &m_Drawcalls.back();
+    while(!m_LastDrawcall->children.empty())
+      m_LastDrawcall = &m_LastDrawcall->children.back();
+
     m_PostloadProgress = 0.4f;
 
     m_WinSystems = r->GetSupportedWindowSystems();
@@ -522,6 +531,9 @@ void CaptureContext::CloseLogfile()
   m_Textures.clear();
   m_TextureList.clear();
 
+  m_Drawcalls.clear();
+  m_FirstDrawcall = m_LastDrawcall = NULL;
+
   m_CurD3D11PipelineState = D3D11Pipe::State();
   m_CurD3D12PipelineState = D3D12Pipe::State();
   m_CurGLPipelineState = GLPipe::State();

qrenderdoc/Code/CaptureContext.h

@@ -105,6 +105,8 @@ public:
     return GetDrawcall(CurSelectedEvent());
   }
   const DrawcallDescription *CurDrawcall() override { return GetDrawcall(CurEvent()); }
+  const DrawcallDescription *GetFirstDrawcall() override { return m_FirstDrawcall; };
+  const DrawcallDescription *GetLastDrawcall() override { return m_LastDrawcall; };
   const rdctype::array<DrawcallDescription> &CurDrawcalls() override { return m_Drawcalls; }
   TextureDescription *GetTexture(ResourceId id) override { return m_Textures[id]; }
   const rdctype::array<TextureDescription> &GetTextures() override { return m_TextureList; }
@@ -248,6 +250,8 @@ private:
 
   APIProperties m_APIProps;
   FrameDescription m_FrameInfo;
+  DrawcallDescription *m_FirstDrawcall = NULL;
+  DrawcallDescription *m_LastDrawcall = NULL;
 
   QMap<ResourceId, TextureDescription *> m_Textures;
   rdctype::array<TextureDescription> m_TextureList;

qrenderdoc/Code/Interface/QRDInterface.h

@@ -960,11 +960,25 @@ more information for how this differs.
 
   DOCUMENT(R"(Retrieve the current drawcall.
 
-:return: The current drawcall.
+:return: The current drawcall, or ``None`` if no drawcall is selected.
 :rtype: ~renderdoc.DrawcallDescription
 )");
   virtual const DrawcallDescription *CurDrawcall() = 0;
 
+  DOCUMENT(R"(Retrieve the first drawcall in the capture.
+
+:return: The first drawcall.
+:rtype: ~renderdoc.DrawcallDescription
+)");
+  virtual const DrawcallDescription *GetFirstDrawcall() = 0;
+
+  DOCUMENT(R"(Retrieve the last drawcall in the capture.
+
+:return: The last drawcall.
+:rtype: ~renderdoc.DrawcallDescription
+)");
+  virtual const DrawcallDescription *GetLastDrawcall() = 0;
+
   DOCUMENT(R"(Retrieve the root list of drawcalls in the current capture.
 
 :return: The root drawcalls.

qrenderdoc/Windows/EventBrowser.cpp

@@ -175,7 +175,7 @@ void EventBrowser::OnLogfileLoaded()
 
   RDTreeWidgetItem *framestart =
       new RDTreeWidgetItem({tr("Frame Start"), lit("0"), lit("0"), QString()});
-  framestart->setTag(QVariant::fromValue(EventItemTag()));
+  framestart->setTag(QVariant::fromValue(EventItemTag(0, 0)));
 
   frame->addChild(framestart);
 
@@ -403,6 +403,14 @@ void EventBrowser::on_events_currentItemChanged(RDTreeWidgetItem *current, RDTre
   ui->stepPrev->setEnabled(draw && draw->previous);
   ui->stepNext->setEnabled(draw && draw->next);
 
+  // special case for the first draw in the frame
+  if(tag.lastEID == 0)
+    ui->stepNext->setEnabled(true);
+
+  // special case for the first 'virtual' draw at EID 0
+  if(tag.lastEID == m_Ctx.GetFirstDrawcall()->eventID)
+    ui->stepPrev->setEnabled(true);
+
   highlightBookmarks();
 }
 
@@ -502,6 +510,10 @@ void EventBrowser::on_stepNext_clicked()
 
   if(draw && draw->next > 0)
     SelectEvent(draw->next);
+
+  // special case for the first 'virtual' draw at EID 0
+  if(m_Ctx.CurEvent() == 0)
+    SelectEvent(m_Ctx.GetFirstDrawcall()->eventID);
 }
 
 void EventBrowser::on_stepPrev_clicked()
@@ -513,6 +525,10 @@ void EventBrowser::on_stepPrev_clicked()
 
   if(draw && draw->previous > 0)
     SelectEvent(draw->previous);
+
+  // special case for the first 'virtual' draw at EID 0
+  if(m_Ctx.CurEvent() == m_Ctx.GetFirstDrawcall()->eventID)
+    SelectEvent(0);
 }
 
 void EventBrowser::on_exportDraws_clicked()

qrenderdoc/Windows/PythonShell.cpp

@@ -68,6 +68,11 @@ struct CaptureContextInvoker : ICaptureContext
     return m_Ctx.CurSelectedDrawcall();
   }
   virtual const DrawcallDescription *CurDrawcall() override { return m_Ctx.CurDrawcall(); }
+  virtual const DrawcallDescription *GetFirstDrawcall() override
+  {
+    return m_Ctx.GetFirstDrawcall();
+  }
+  virtual const DrawcallDescription *GetLastDrawcall() override { return m_Ctx.GetLastDrawcall(); }
   virtual const rdctype::array<DrawcallDescription> &CurDrawcalls() override
   {
     return m_Ctx.CurDrawcalls();

qrenderdoc/Windows/StatisticsViewer.cpp

@@ -686,17 +686,14 @@ void StatisticsViewer::GenerateReport()
 {
   const rdctype::array<DrawcallDescription> &curDraws = m_Ctx.CurDrawcalls();
 
-  const DrawcallDescription *lastDraw = &curDraws.back();
-  while(!lastDraw->children.empty())
-    lastDraw = &lastDraw->children.back();
-
   uint32_t drawCount = 0;
   uint32_t dispatchCount = 0;
   uint32_t diagnosticCount = 0;
   for(const DrawcallDescription &d : curDraws)
     CountContributingEvents(d, drawCount, dispatchCount, diagnosticCount);
 
-  uint32_t numAPIcalls = lastDraw->eventID - (drawCount + dispatchCount + diagnosticCount);
+  uint32_t numAPIcalls =
+      m_Ctx.GetLastDrawcall()->eventID - (drawCount + dispatchCount + diagnosticCount);
 
   int numTextures = m_Ctx.GetTextures().count;
   int numBuffers = m_Ctx.GetBuffers().count;