From 1e65762e937ffc3fc2ac27844002eadb22e2f669 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Fri, 17 Feb 2017 13:43:19 +0000
Subject: [PATCH] Process render commands 1 by 1 to allow pre-empting high
 frequency cmds

---
 qrenderdoc/Code/RenderManager.cpp    | 60 +++++++++++++++++++---------
 qrenderdoc/Code/RenderManager.h      | 11 ++++-
 qrenderdoc/Windows/BufferViewer.cpp  |  2 +-
 qrenderdoc/Windows/TextureViewer.cpp |  6 ++-
 4 files changed, 57 insertions(+), 22 deletions(-)

diff --git a/qrenderdoc/Code/RenderManager.cpp b/qrenderdoc/Code/RenderManager.cpp
index 7c54f1dfa..62832449b 100644
--- a/qrenderdoc/Code/RenderManager.cpp
+++ b/qrenderdoc/Code/RenderManager.cpp
@@ -231,6 +231,31 @@ bool RenderManager::IsRunning()
   return m_Thread && m_Thread->isRunning() && m_Running;
 }
 
+void RenderManager::AsyncInvoke(const QString &tag, RenderManager::InvokeMethod m)
+{
+  {
+    QMutexLocker autolock(&m_RenderLock);
+    for(int i = 0; i < m_RenderQueue.count();)
+    {
+      if(m_RenderQueue[i]->tag == tag)
+      {
+        InvokeHandle *cmd = m_RenderQueue.takeAt(i);
+        if(cmd->selfdelete)
+          delete cmd;
+      }
+      else
+      {
+        i++;
+      }
+    }
+  }
+
+  InvokeHandle *cmd = new InvokeHandle(m, tag);
+  cmd->selfdelete = true;
+
+  PushInvoke(cmd);
+}
+
 void RenderManager::AsyncInvoke(RenderManager::InvokeMethod m)
 {
   InvokeHandle *cmd = new InvokeHandle(m);
@@ -373,7 +398,7 @@ void RenderManager::PushInvoke(RenderManager::InvokeHandle *cmd)
   }
 
   QMutexLocker autolock(&m_RenderLock);
-  m_RenderQueue.push_back(cmd);
+  m_RenderQueue.enqueue(cmd);
   m_RenderCondition.wakeAll();
 }
 
@@ -396,31 +421,30 @@ void RenderManager::run()
   // main render command loop
   while(m_Running)
   {
-    QQueue<InvokeHandle *> queue;
+    InvokeHandle *cmd = NULL;
 
-    // wait for the condition to be woken, grab current queue,
+    // wait for the condition to be woken, grab top of current queue,
     // unlock again.
     {
       QMutexLocker autolock(&m_RenderLock);
-      m_RenderCondition.wait(&m_RenderLock, 10);
-      m_RenderQueue.swap(queue);
+      if(m_RenderQueue.isEmpty())
+        m_RenderCondition.wait(&m_RenderLock, 10);
+
+      if(!m_RenderQueue.isEmpty())
+        cmd = m_RenderQueue.dequeue();
     }
 
-    // process all the commands
-    for(InvokeHandle *cmd : queue)
-    {
-      if(cmd == NULL)
-        continue;
+    if(cmd == NULL)
+      continue;
 
-      if(cmd->method != NULL)
-        cmd->method(renderer);
+    if(cmd->method != NULL)
+      cmd->method(renderer);
 
-      // if it's a throwaway command, delete it
-      if(cmd->selfdelete)
-        delete cmd;
-      else
-        cmd->processed.release();
-    }
+    // if it's a throwaway command, delete it
+    if(cmd->selfdelete)
+      delete cmd;
+    else
+      cmd->processed.release();
   }
 
   // clean up anything left in the queue
diff --git a/qrenderdoc/Code/RenderManager.h b/qrenderdoc/Code/RenderManager.h
index 4d7b579c7..969a8992c 100644
--- a/qrenderdoc/Code/RenderManager.h
+++ b/qrenderdoc/Code/RenderManager.h
@@ -131,6 +131,13 @@ public:
 
   bool IsRunning();
   ReplayCreateStatus GetCreateStatus() { return m_CreateStatus; }
+  // this tagged version is for cases when we might send a request - e.g. to pick a vertex or pixel
+  // - and want to pre-empt it with a new request before the first has returned. Either because some
+  // other work is taking a while or because we're sending requests faster than they can be
+  // processed.
+  // the manager processes only the request on the top of the queue, so when a new tagged invoke
+  // comes in, we remove any other requests in the queue before it that have the same tag
+  void AsyncInvoke(const QString &tag, InvokeMethod m);
   void AsyncInvoke(InvokeMethod m);
   void BlockInvoke(InvokeMethod m);
 
@@ -155,12 +162,14 @@ public:
 private:
   struct InvokeHandle
   {
-    InvokeHandle(InvokeMethod m)
+    InvokeHandle(InvokeMethod m, const QString &t = QString())
     {
+      tag = t;
       method = m;
       selfdelete = false;
     }
 
+    QString tag;
     InvokeMethod method;
     QSemaphore processed;
     bool selfdelete;
diff --git a/qrenderdoc/Windows/BufferViewer.cpp b/qrenderdoc/Windows/BufferViewer.cpp
index f560bf6f4..0216e7ca5 100644
--- a/qrenderdoc/Windows/BufferViewer.cpp
+++ b/qrenderdoc/Windows/BufferViewer.cpp
@@ -1889,7 +1889,7 @@ void BufferViewer::render_clicked(QMouseEvent *e)
 
   if((e->buttons() & Qt::RightButton) && m_Output)
   {
-    m_Ctx.Renderer().AsyncInvoke([this, curpos](IReplayRenderer *r) {
+    m_Ctx.Renderer().AsyncInvoke("PickVertex", [this, curpos](IReplayRenderer *r) {
       uint32_t instanceSelected = 0;
       uint32_t vertSelected = m_Output->PickVertex(m_Ctx.CurEvent(), (uint32_t)curpos.x(),
                                                    (uint32_t)curpos.y(), &instanceSelected);
diff --git a/qrenderdoc/Windows/TextureViewer.cpp b/qrenderdoc/Windows/TextureViewer.cpp
index 5b0772275..469f267e6 100644
--- a/qrenderdoc/Windows/TextureViewer.cpp
+++ b/qrenderdoc/Windows/TextureViewer.cpp
@@ -2185,11 +2185,13 @@ void TextureViewer::render_mouseMove(QMouseEvent *e)
         m_PickedPoint.setX(qBound(0, m_PickedPoint.x(), (int)texptr->width - 1));
         m_PickedPoint.setY(qBound(0, m_PickedPoint.y(), (int)texptr->height - 1));
 
-        INVOKE_MEMFN(RT_PickPixelsAndUpdate);
+        m_Ctx.Renderer().AsyncInvoke("PickPixelClick",
+                                     [this](IReplayRenderer *r) { RT_PickPixelsAndUpdate(r); });
       }
       else if(e->buttons() == Qt::NoButton)
       {
-        INVOKE_MEMFN(RT_PickHoverAndUpdate);
+        m_Ctx.Renderer().AsyncInvoke("PickPixelHover",
+                                     [this](IReplayRenderer *r) { RT_PickHoverAndUpdate(r); });
       }
     }
   }