VideoCommon: Support hot reloading of VS expand

Source/Core/DolphinQt/Config/Graphics/AdvancedWidget.cpp

@@ -202,7 +202,6 @@ void AdvancedWidget::OnBackendChanged()
 {
   m_backend_multithreading->setEnabled(g_Config.backend_info.bSupportsMultithreading);
   m_prefer_vs_for_point_line_expansion->setEnabled(
-      Core::GetState() == Core::State::Uninitialized &&
       g_Config.backend_info.bSupportsGeometryShaders &&
       g_Config.backend_info.bSupportsVSLinePointExpand);
   AddDescriptions();
@@ -211,10 +210,6 @@ void AdvancedWidget::OnBackendChanged()
 void AdvancedWidget::OnEmulationStateChanged(bool running)
 {
   m_enable_prog_scan->setEnabled(!running);
-  m_prefer_vs_for_point_line_expansion->setEnabled(
-      !running &&
-      g_Config.backend_info.bSupportsGeometryShaders &&
-      g_Config.backend_info.bSupportsVSLinePointExpand);
 }
 
 void AdvancedWidget::AddDescriptions()

Source/Core/VideoCommon/RenderBase.cpp

@@ -488,6 +488,7 @@ void Renderer::CheckForConfigChanges()
 
   UpdateActiveConfig();
   FreeLook::UpdateActiveConfig();
+  g_vertex_manager->OnConfigChange();
 
   g_freelook_camera.SetControlType(FreeLook::GetActiveConfig().camera_config.control_type);
 

Source/Core/VideoCommon/VertexManagerBase.cpp

@@ -826,6 +826,12 @@ void VertexManagerBase::UpdatePipelineObject()
   }
 }
 
+void VertexManagerBase::OnConfigChange()
+{
+  // Reload index generator function tables in case VS expand config changed
+  m_index_generator.Init();
+}
+
 void VertexManagerBase::OnDraw()
 {
   m_draw_counter++;

Source/Core/VideoCommon/VertexManagerBase.h

@@ -140,6 +140,9 @@ public:
                                  u32* out_offset, const void* palette_data, u32 palette_size,
                                  TexelBufferFormat palette_format, u32* out_palette_offset);
 
+  // Call if active config changes
+  void OnConfigChange();
+
   // CPU access tracking - call after a draw call is made.
   void OnDraw();