Try to preserve selected pipeline stage as much as possible

* When switching between mesh/normal pipeline keep the same stage selected if
  it's a common stage even if the index has changed.

qrenderdoc/Widgets/PipelineFlowChart.cpp

@@ -38,6 +38,15 @@ PipelineFlowChart::~PipelineFlowChart()
 
 void PipelineFlowChart::setStages(const QStringList &abbrevs, const QStringList &names)
 {
+  int prev = -1;
+  QString prevAbbrev;
+
+  if(!m_StageNames.empty() && names.count() != m_StageNames.count())
+  {
+    prev = m_SelectedStage;
+    prevAbbrev = m_StageAbbrevs[prev];
+  }
+
   m_StageNames = names;
   m_StageAbbrevs = abbrevs;
   m_StageFlows.reserve(m_StageNames.count());
@@ -51,7 +60,41 @@ void PipelineFlowChart::setStages(const QStringList &abbrevs, const QStringList
   }
 
   update();
-  setSelectedStage(selectedStage());
+
+  if(prev >= 0)
+  {
+    int exact = m_StageAbbrevs.indexOf(prevAbbrev);
+
+    if(exact >= 0)
+    {
+      setSelectedStage(exact);
+    }
+    else
+    {
+      // this is most likely a change between mesh/vertex pipeline, default to either the mesh
+      // shader or vertex shader if we can find it. Fortunately those names are identical
+      int vert = m_StageNames.indexOf(tr("Vertex Shader"));
+      int mesh = m_StageNames.indexOf(tr("Mesh Shader"));
+
+      if(vert >= 0)
+      {
+        setSelectedStage(vert);
+      }
+      else if(mesh >= 0)
+      {
+        setSelectedStage(mesh);
+      }
+      else
+      {
+        qWarning() << "Couldn't find default stage when names changed";
+        setSelectedStage(selectedStage());
+      }
+    }
+  }
+  else
+  {
+    setSelectedStage(selectedStage());
+  }
 }
 
 void PipelineFlowChart::setStageName(int index, const QString &abbrev, const QString &name)

qrenderdoc/Windows/PipelineState/VulkanPipelineStateViewer.cpp

@@ -1794,6 +1794,8 @@ void VulkanPipelineStateViewer::setState()
       raster = false;
     }
 
+    setOldMeshPipeFlow();
+
     if(state.geometryShader.resourceId == ResourceId() && xfbActive)
     {
       ui->pipeFlow->setStageName(4, lit("XFB"), tr("Transform Feedback"));
@@ -1803,7 +1805,6 @@ void VulkanPipelineStateViewer::setState()
       ui->pipeFlow->setStageName(4, lit("GS"), tr("Geometry Shader"));
     }
 
-    setOldMeshPipeFlow();
     ui->pipeFlow->setStagesEnabled(
         {true, true, state.tessControlShader.resourceId != ResourceId(),
          state.tessEvalShader.resourceId != ResourceId(),