VideoBackends:Metal: MSAA support

Source/Core/VideoCommon/FramebufferManager.cpp

@@ -188,12 +188,23 @@ bool FramebufferManager::CreateEFBFramebuffer()
   // Create resolved textures if MSAA is on
   if (g_ActiveConfig.MultisamplingEnabled())
   {
+    u32 flags = 0;
+    if (!g_ActiveConfig.backend_info.bSupportsPartialMultisampleResolve)
+      flags |= AbstractTextureFlag_RenderTarget;
     m_efb_resolve_color_texture = g_renderer->CreateTexture(
         TextureConfig(efb_color_texture_config.width, efb_color_texture_config.height, 1,
-                      efb_color_texture_config.layers, 1, efb_color_texture_config.format, 0),
+                      efb_color_texture_config.layers, 1, efb_color_texture_config.format, flags),
         "EFB color resolve texture");
     if (!m_efb_resolve_color_texture)
       return false;
+
+    if (!g_ActiveConfig.backend_info.bSupportsPartialMultisampleResolve)
+    {
+      m_efb_color_resolve_framebuffer =
+          g_renderer->CreateFramebuffer(m_efb_resolve_color_texture.get(), nullptr);
+      if (!m_efb_color_resolve_framebuffer)
+        return false;
+    }
   }
 
   // We also need one to convert the D24S8 to R32F if that is being used (Adreno).
@@ -248,12 +259,27 @@ AbstractTexture* FramebufferManager::ResolveEFBColorTexture(const MathUtil::Rect
   clamped_region.ClampUL(0, 0, GetEFBWidth(), GetEFBHeight());
 
   // Resolve to our already-created texture.
-  for (u32 layer = 0; layer < GetEFBLayers(); layer++)
+  if (g_ActiveConfig.backend_info.bSupportsPartialMultisampleResolve)
   {
-    m_efb_resolve_color_texture->ResolveFromTexture(m_efb_color_texture.get(), clamped_region,
-                                                    layer, 0);
+    for (u32 layer = 0; layer < GetEFBLayers(); layer++)
+    {
+      m_efb_resolve_color_texture->ResolveFromTexture(m_efb_color_texture.get(), clamped_region,
+                                                      layer, 0);
+    }
+  }
+  else
+  {
+    m_efb_color_texture->FinishedRendering();
+    g_renderer->BeginUtilityDrawing();
+    g_renderer->SetAndDiscardFramebuffer(m_efb_color_resolve_framebuffer.get());
+    g_renderer->SetPipeline(m_efb_color_resolve_pipeline.get());
+    g_renderer->SetTexture(0, m_efb_color_texture.get());
+    g_renderer->SetSamplerState(0, RenderState::GetPointSamplerState());
+    g_renderer->SetViewportAndScissor(clamped_region);
+    g_renderer->Draw(0, 3);
+    m_efb_resolve_color_texture->FinishedRendering();
+    g_renderer->EndUtilityDrawing();
   }
-
   m_efb_resolve_color_texture->FinishedRendering();
   return m_efb_resolve_color_texture.get();
 }
@@ -487,6 +513,22 @@ bool FramebufferManager::CompileReadbackPipelines()
     m_efb_depth_resolve_pipeline = g_renderer->CreatePipeline(config);
     if (!m_efb_depth_resolve_pipeline)
       return false;
+
+    if (!g_ActiveConfig.backend_info.bSupportsPartialMultisampleResolve)
+    {
+      config.framebuffer_state.color_texture_format = GetEFBColorFormat();
+      auto color_resolve_shader = g_renderer->CreateShaderFromSource(
+          ShaderStage::Pixel,
+          FramebufferShaderGen::GenerateResolveColorPixelShader(GetEFBSamples()),
+          "Color resolve pixel shader");
+      if (!color_resolve_shader)
+        return false;
+
+      config.pixel_shader = color_resolve_shader.get();
+      m_efb_color_resolve_pipeline = g_renderer->CreatePipeline(config);
+      if (!m_efb_color_resolve_pipeline)
+        return false;
+    }
   }
 
   // EFB restore pipeline

Source/Core/VideoCommon/FramebufferManager.h

@@ -170,7 +170,9 @@ protected:
 
   std::unique_ptr<AbstractFramebuffer> m_efb_framebuffer;
   std::unique_ptr<AbstractFramebuffer> m_efb_convert_framebuffer;
+  std::unique_ptr<AbstractFramebuffer> m_efb_color_resolve_framebuffer;
   std::unique_ptr<AbstractFramebuffer> m_efb_depth_resolve_framebuffer;
+  std::unique_ptr<AbstractPipeline> m_efb_color_resolve_pipeline;
   std::unique_ptr<AbstractPipeline> m_efb_depth_resolve_pipeline;
 
   // Pipeline for restoring the contents of the EFB from a save state

Source/Core/VideoCommon/FramebufferShaderGen.cpp

@@ -338,6 +338,22 @@ std::string GenerateColorPixelShader()
   return code.GetBuffer();
 }
 
+std::string GenerateResolveColorPixelShader(u32 samples)
+{
+  ShaderCode code;
+  EmitSamplerDeclarations(code, 0, 1, true);
+  EmitPixelMainDeclaration(code, 1, 0);
+  code.Write("{{\n"
+             "  int layer = int(v_tex0.z);\n"
+             "  int3 coords = int3(int2(gl_FragCoord.xy), layer);\n"
+             "  ocol0 = float4(0.0f);\n");
+  code.Write("  for (int i = 0; i < {}; i++)\n", samples);
+  code.Write("    ocol0 += texelFetch(samp0, coords, i);\n");
+  code.Write("  ocol0 /= {}.0f;\n", samples);
+  code.Write("}}\n");
+  return code.GetBuffer();
+}
+
 std::string GenerateResolveDepthPixelShader(u32 samples)
 {
   ShaderCode code;

Source/Core/VideoCommon/FramebufferShaderGen.h

@@ -15,6 +15,7 @@ std::string GenerateScreenQuadVertexShader();
 std::string GeneratePassthroughGeometryShader(u32 num_tex, u32 num_colors);
 std::string GenerateTextureCopyVertexShader();
 std::string GenerateTextureCopyPixelShader();
+std::string GenerateResolveColorPixelShader(u32 samples);
 std::string GenerateResolveDepthPixelShader(u32 samples);
 std::string GenerateClearVertexShader();
 std::string GenerateEFBPokeVertexShader();

Source/Core/VideoCommon/VideoConfig.h

@@ -238,6 +238,7 @@ struct VideoConfig final
     bool bSupportsTextureQueryLevels = false;
     bool bSupportsLodBiasInSampler = false;
     bool bSupportsSettingObjectNames = false;
+    bool bSupportsPartialMultisampleResolve = false;
   } backend_info;
 
   // Utility