VideoCommon: Cull vertices on the CPU

Source/Core/Core/Config/GraphicsSettings.cpp

@@ -93,6 +93,7 @@ const Info<bool> GFX_SAVE_TEXTURE_CACHE_TO_STATE{
     {System::GFX, "Settings", "SaveTextureCacheToState"}, true};
 const Info<bool> GFX_PREFER_VS_FOR_LINE_POINT_EXPANSION{
     {System::GFX, "Settings", "PreferVSForLinePointExpansion"}, false};
+const Info<bool> GFX_CPU_CULL{{System::GFX, "Settings", "CPUCull"}, false};
 
 const Info<TriState> GFX_MTL_MANUALLY_UPLOAD_BUFFERS{
     {System::GFX, "Settings", "ManuallyUploadBuffers"}, TriState::Auto};

Source/Core/Core/Config/GraphicsSettings.h

@@ -82,6 +82,7 @@ extern const Info<int> GFX_SHADER_COMPILER_THREADS;
 extern const Info<int> GFX_SHADER_PRECOMPILER_THREADS;
 extern const Info<bool> GFX_SAVE_TEXTURE_CACHE_TO_STATE;
 extern const Info<bool> GFX_PREFER_VS_FOR_LINE_POINT_EXPANSION;
+extern const Info<bool> GFX_CPU_CULL;
 
 extern const Info<TriState> GFX_MTL_MANUALLY_UPLOAD_BUFFERS;
 extern const Info<bool> GFX_MTL_USE_PRESENT_DRAWABLE;

Source/Core/VideoCommon/VertexLoaderManager.cpp

@@ -30,6 +30,7 @@
 #include "VideoCommon/VertexLoaderBase.h"
 #include "VideoCommon/VertexManagerBase.h"
 #include "VideoCommon/VertexShaderManager.h"
+#include "VideoCommon/VideoConfig.h"
 #include "VideoCommon/XFMemory.h"
 
 namespace VertexLoaderManager
@@ -366,17 +367,33 @@ int RunVertices(int vtx_attr_group, OpcodeDecoder::Primitive primitive, int coun
     vertex_shader_manager.SetVertexFormat(loader->m_native_components,
                                           loader->m_native_vertex_format->GetVertexDeclaration());
 
-    // if cull mode is CULL_ALL, tell VertexManager to skip triangles and quads.
-    // They still need to go through vertex loading, because we need to calculate a zfreeze refrence
-    // slope.
-    bool cullall = (bpmem.genMode.cullmode == CullMode::All &&
-                    primitive < OpcodeDecoder::Primitive::GX_DRAW_LINES);
+    // CPUCull's performance increase comes from encoding fewer GPU commands, not sending less data
+    // Therefore it's only useful to check if culling could remove a flush
+    const bool can_cpu_cull = g_ActiveConfig.bCPUCull &&
+                              primitive < OpcodeDecoder::Primitive::GX_DRAW_LINES &&
+                              !g_vertex_manager->HasSendableVertices();
 
-    DataReader dst = g_vertex_manager->PrepareForAdditionalData(
-        primitive, count, loader->m_native_vtx_decl.stride, cullall);
+    // if cull mode is CULL_ALL, tell VertexManager to skip triangles and quads.
+    // They still need to go through vertex loading, because we need to calculate a zfreeze
+    // reference slope.
+    const bool cullall = (bpmem.genMode.cullmode == CullMode::All &&
+                          primitive < OpcodeDecoder::Primitive::GX_DRAW_LINES);
+
+    const int stride = loader->m_native_vtx_decl.stride;
+    DataReader dst = g_vertex_manager->PrepareForAdditionalData(primitive, count, stride,
+                                                                cullall || can_cpu_cull);
 
     count = loader->RunVertices(src, dst.GetPointer(), count);
 
+    if (can_cpu_cull && !cullall)
+    {
+      if (!g_vertex_manager->AreAllVerticesCulled(loader, primitive, dst.GetPointer(), count))
+      {
+        DataReader new_dst = g_vertex_manager->DisableCullAll(stride);
+        memmove(new_dst.GetPointer(), dst.GetPointer(), count * stride);
+      }
+    }
+
     g_vertex_manager->AddIndices(primitive, count);
     g_vertex_manager->FlushData(count, loader->m_native_vtx_decl.stride);
 

Source/Core/VideoCommon/VertexManagerBase.cpp

@@ -104,6 +104,7 @@ VertexManagerBase::~VertexManagerBase() = default;
 bool VertexManagerBase::Initialize()
 {
   m_index_generator.Init();
+  m_cpu_cull.Init();
   return true;
 }
 
@@ -117,6 +118,13 @@ void VertexManagerBase::AddIndices(OpcodeDecoder::Primitive primitive, u32 num_v
   m_index_generator.AddIndices(primitive, num_vertices);
 }
 
+bool VertexManagerBase::AreAllVerticesCulled(VertexLoaderBase* loader,
+                                             OpcodeDecoder::Primitive primitive, const u8* src,
+                                             u32 count)
+{
+  return m_cpu_cull.AreAllVerticesCulled(loader, primitive, src, count);
+}
+
 DataReader VertexManagerBase::PrepareForAdditionalData(OpcodeDecoder::Primitive primitive,
                                                        u32 count, u32 stride, bool cullall)
 {
@@ -185,6 +193,16 @@ DataReader VertexManagerBase::PrepareForAdditionalData(OpcodeDecoder::Primitive
   return DataReader(m_cur_buffer_pointer, m_end_buffer_pointer);
 }
 
+DataReader VertexManagerBase::DisableCullAll(u32 stride)
+{
+  if (m_cull_all)
+  {
+    m_cull_all = false;
+    ResetBuffer(stride);
+  }
+  return DataReader(m_cur_buffer_pointer, m_end_buffer_pointer);
+}
+
 void VertexManagerBase::FlushData(u32 count, u32 stride)
 {
   m_cur_buffer_pointer += count * stride;
@@ -546,6 +564,8 @@ void VertexManagerBase::Flush()
     // Now the vertices can be flushed to the GPU. Everything following the CommitBuffer() call
     // must be careful to not upload any utility vertices, as the binding will be lost otherwise.
     const u32 num_indices = m_index_generator.GetIndexLen();
+    if (num_indices == 0)
+      return;
     u32 base_vertex, base_index;
     CommitBuffer(m_index_generator.GetNumVerts(),
                  VertexLoaderManager::GetCurrentVertexFormat()->GetVertexStride(), num_indices,

Source/Core/VideoCommon/VertexManagerBase.h

@@ -9,6 +9,7 @@
 #include "Common/BitSet.h"
 #include "Common/CommonTypes.h"
 #include "Common/MathUtil.h"
+#include "VideoCommon/CPUCull.h"
 #include "VideoCommon/IndexGenerator.h"
 #include "VideoCommon/RenderState.h"
 #include "VideoCommon/ShaderCache.h"
@@ -100,11 +101,18 @@ public:
 
   PrimitiveType GetCurrentPrimitiveType() const { return m_current_primitive_type; }
   void AddIndices(OpcodeDecoder::Primitive primitive, u32 num_vertices);
+  bool AreAllVerticesCulled(VertexLoaderBase* loader, OpcodeDecoder::Primitive primitive,
+                            const u8* src, u32 count);
   virtual DataReader PrepareForAdditionalData(OpcodeDecoder::Primitive primitive, u32 count,
                                               u32 stride, bool cullall);
+  /// Switch cullall off after a call to PrepareForAdditionalData with cullall true
+  /// Expects that you will add a nonzero number of primitives before the next flush
+  /// Returns whether cullall was changed (false if cullall was already off)
+  DataReader DisableCullAll(u32 stride);
   void FlushData(u32 count, u32 stride);
 
   void Flush();
+  bool HasSendableVertices() const { return !m_is_flushed && !m_cull_all; }
 
   void DoState(PointerWrap& p);
 
@@ -201,6 +209,7 @@ protected:
   bool m_cull_all = false;
 
   IndexGenerator m_index_generator;
+  CPUCull m_cpu_cull;
 
 private:
   // Minimum number of draws per command buffer when attempting to preempt a readback operation.

Source/Core/VideoCommon/VideoConfig.cpp

@@ -113,6 +113,7 @@ void VideoConfig::Refresh()
   iShaderCompilationMode = Config::Get(Config::GFX_SHADER_COMPILATION_MODE);
   iShaderCompilerThreads = Config::Get(Config::GFX_SHADER_COMPILER_THREADS);
   iShaderPrecompilerThreads = Config::Get(Config::GFX_SHADER_PRECOMPILER_THREADS);
+  bCPUCull = Config::Get(Config::GFX_CPU_CULL);
 
   texture_filtering_mode = Config::Get(Config::GFX_ENHANCE_FORCE_TEXTURE_FILTERING);
   iMaxAnisotropy = Config::Get(Config::GFX_ENHANCE_MAX_ANISOTROPY);

Source/Core/VideoCommon/VideoConfig.h

@@ -138,6 +138,7 @@ struct VideoConfig final
   bool bPerfQueriesEnable = false;
   bool bBBoxEnable = false;
   bool bForceProgressive = false;
+  bool bCPUCull = false;
 
   bool bEFBEmulateFormatChanges = false;
   bool bSkipEFBCopyToRam = false;