DriverDetails: Add broken discard with early-Z bug on Apple Silicon GPUs

Source/Core/VideoBackends/Vulkan/VKPipeline.cpp

@@ -133,7 +133,7 @@ static VkPipelineDepthStencilStateCreateInfo GetVulkanDepthStencilState(const De
 }
 
 static VkPipelineColorBlendAttachmentState
-GetVulkanAttachmentBlendState(const BlendingState& state)
+GetVulkanAttachmentBlendState(const BlendingState& state, AbstractPipelineUsage usage)
 {
   VkPipelineColorBlendAttachmentState vk_state = {};
 
@@ -143,7 +143,8 @@ GetVulkanAttachmentBlendState(const BlendingState& state)
   bool use_shader_blend = !use_dual_source && state.usedualsrc && state.dstalpha &&
                           g_ActiveConfig.backend_info.bSupportsFramebufferFetch;
 
-  if (use_shader_blend)
+  if (use_shader_blend || (usage == AbstractPipelineUsage::GX &&
+                           DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z)))
   {
     vk_state.blendEnable = VK_FALSE;
   }
@@ -349,7 +350,7 @@ std::unique_ptr<VKPipeline> VKPipeline::Create(const AbstractPipelineConfig& con
   VkPipelineDepthStencilStateCreateInfo depth_stencil_state =
       GetVulkanDepthStencilState(config.depth_state);
   VkPipelineColorBlendAttachmentState blend_attachment_state =
-      GetVulkanAttachmentBlendState(config.blending_state);
+      GetVulkanAttachmentBlendState(config.blending_state, config.usage);
   VkPipelineColorBlendStateCreateInfo blend_state =
       GetVulkanColorBlendState(config.blending_state, &blend_attachment_state, 1);
 

Source/Core/VideoBackends/Vulkan/VulkanContext.cpp

@@ -366,6 +366,13 @@ void VulkanContext::PopulateBackendInfoFeatures(VideoConfig* config, VkPhysicalD
   // with depth clamping. Fall back to inverted depth range for these.
   if (DriverDetails::HasBug(DriverDetails::BUG_BROKEN_REVERSED_DEPTH_RANGE))
     config->backend_info.bSupportsReversedDepthRange = false;
+
+  // Calling discard when early depth test is enabled can break on some Apple Silicon GPU drivers.
+  if (DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z))
+  {
+    // We will use shader blending, so disable hardware dual source blending.
+    config->backend_info.bSupportsDualSourceBlend = false;
+  }
 }
 
 void VulkanContext::PopulateBackendInfoMultisampleModes(

Source/Core/VideoCommon/DriverDetails.cpp

@@ -136,6 +136,8 @@ constexpr BugInfo m_known_bugs[] = {
      BUG_BROKEN_MULTITHREADED_SHADER_PRECOMPILATION, -1.0, -1.0, true},
     {API_VULKAN, OS_ANDROID, VENDOR_ALL, DRIVER_ALL, Family::UNKNOWN,
      BUG_BROKEN_MULTITHREADED_SHADER_PRECOMPILATION, -1.0, -1.0, true},
+    {API_VULKAN, OS_OSX, VENDOR_APPLE, DRIVER_PORTABILITY, Family::UNKNOWN,
+     BUG_BROKEN_DISCARD_WITH_EARLY_Z, -1.0, -1.0, true},
 };
 
 static std::map<Bug, BugInfo> m_bugs;

Source/Core/VideoCommon/DriverDetails.h

@@ -319,7 +319,15 @@ enum Bug
   // BUG: Multi-threaded shader pre-compilation sometimes crashes
   // Used primarily in Videoconfig.cpp's GetNumAutoShaderPreCompilerThreads()
   // refer to https://github.com/dolphin-emu/dolphin/pull/9414 for initial validation coverage
-  BUG_BROKEN_MULTITHREADED_SHADER_PRECOMPILATION
+  BUG_BROKEN_MULTITHREADED_SHADER_PRECOMPILATION,
+
+  // BUG: Some driver and Apple Silicon GPU combinations have problems with fragment discard when
+  // early depth test is enabled. Discarded fragments may appear corrupted (Super Mario Sunshine,
+  // Sonic Adventure 2: Battle, Phantasy Star Online Epsiodes 1 & 2, etc).
+  // Affected devices: Apple Silicon GPUs of Apple family 4 and newer.
+  // Started version: -1
+  // Ended version: -1
+  BUG_BROKEN_DISCARD_WITH_EARLY_Z,
 };
 
 // Initializes our internal vendor, device family, and driver version

Source/Core/VideoCommon/PixelShaderGen.cpp

@@ -320,7 +320,9 @@ PixelShaderUid GetPixelShaderUid()
   BlendingState state = {};
   state.Generate(bpmem);
 
-  if (state.usedualsrc && state.dstalpha && g_ActiveConfig.backend_info.bSupportsFramebufferFetch &&
+  if (((state.usedualsrc && state.dstalpha) ||
+       DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z)) &&
+      g_ActiveConfig.backend_info.bSupportsFramebufferFetch &&
       !g_ActiveConfig.backend_info.bSupportsDualSourceBlend)
   {
     uid_data->blend_enable = state.blendenable;
@@ -943,13 +945,15 @@ ShaderCode GeneratePixelShaderCode(APIType api_type, const ShaderHostConfig& hos
       (!DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DUAL_SOURCE_BLENDING) ||
        uid_data->useDstAlpha);
   const bool use_shader_blend =
-      !use_dual_source && (uid_data->useDstAlpha && host_config.backend_shader_framebuffer_fetch);
+      (!use_dual_source && uid_data->useDstAlpha &&
+       host_config.backend_shader_framebuffer_fetch) ||
+      DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z);
   const bool use_shader_logic_op =
       !host_config.backend_logic_op && host_config.backend_shader_framebuffer_fetch;
 
   if (api_type == APIType::OpenGL || api_type == APIType::Vulkan)
   {
-    bool use_framebuffer_fetch = use_shader_blend || use_shader_logic_op;
+    const bool use_framebuffer_fetch = use_shader_blend || use_shader_logic_op;
 
 #ifdef __APPLE__
     // Framebuffer fetch is only supported by Metal, so ensure that we're running Vulkan (MoltenVK)
@@ -1855,9 +1859,23 @@ static void WriteAlphaTest(ShaderCode& out, const pixel_shader_uid_data* uid_dat
   // ZCOMPLOC HACK:
   if (!uid_data->alpha_test_use_zcomploc_hack)
   {
-    out.Write("\t\tdiscard;\n");
-    if (api_type == APIType::D3D)
+#ifdef __APPLE__
+    if (uid_data->forced_early_z &&
+        DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z))
+    {
+      // Instead of using discard, fetch the framebuffer's color value and use it as the output
+      // for this fragment.
+      out.Write("\t\t{} = float4(initial_ocol0.xyz, 1.0);\n",
+                use_dual_source ? "real_ocol0" : "ocol0");
       out.Write("\t\treturn;\n");
+    }
+    else
+#endif
+    {
+      out.Write("\t\tdiscard;\n");
+      if (api_type == APIType::D3D)
+        out.Write("\t\treturn;\n");
+    }
   }
 
   out.Write("\t}}\n");

Source/Core/VideoCommon/UberShaderPixel.cpp

@@ -57,7 +57,9 @@ ShaderCode GenPixelShader(APIType api_type, const ShaderHostConfig& host_config,
   const bool use_shader_blend = !use_dual_source && host_config.backend_shader_framebuffer_fetch;
   const bool use_shader_logic_op =
       !host_config.backend_logic_op && host_config.backend_shader_framebuffer_fetch;
-  const bool use_framebuffer_fetch = use_shader_blend || use_shader_logic_op;
+  const bool use_framebuffer_fetch =
+      use_shader_blend || use_shader_logic_op ||
+      DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z);
   const bool early_depth = uid_data->early_depth != 0;
   const bool per_pixel_depth = uid_data->per_pixel_depth != 0;
   const bool bounding_box = host_config.bounding_box;
@@ -1007,8 +1009,21 @@ ShaderCode GenPixelShader(APIType api_type, const ShaderHostConfig& host_config,
       out.Write("  depth = float(zbuffer_zCoord) / 16777216.0;\n");
   }
 
-  out.Write("  // Alpha Test\n"
-            "  if (bpmem_alphaTest != 0u) {{\n"
+  out.Write("  // Alpha Test\n");
+
+  if (early_depth && DriverDetails::HasBug(DriverDetails::BUG_BROKEN_DISCARD_WITH_EARLY_Z))
+  {
+    // Instead of using discard, fetch the framebuffer's color value and use it as the output
+    // for this fragment.
+    out.Write("  #define discard_fragment {{ {} = float4(initial_ocol0.xyz, 1.0); return; }}\n",
+              use_shader_blend ? "real_ocol0" : "ocol0");
+  }
+  else
+  {
+    out.Write("  #define discard_fragment discard\n");
+  }
+
+  out.Write("  if (bpmem_alphaTest != 0u) {{\n"
             "    bool comp0 = alphaCompare(TevResult.a, " I_ALPHA ".r, {});\n",
             BitfieldExtract<&AlphaTest::comp0>("bpmem_alphaTest"));
   out.Write("    bool comp1 = alphaCompare(TevResult.a, " I_ALPHA ".g, {});\n",
@@ -1019,13 +1034,13 @@ ShaderCode GenPixelShader(APIType api_type, const ShaderHostConfig& host_config,
             "    switch ({}) {{\n",
             BitfieldExtract<&AlphaTest::logic>("bpmem_alphaTest"));
   out.Write("    case 0u: // AND\n"
-            "      if (comp0 && comp1) break; else discard; break;\n"
+            "      if (comp0 && comp1) break; else discard_fragment; break;\n"
             "    case 1u: // OR\n"
-            "      if (comp0 || comp1) break; else discard; break;\n"
+            "      if (comp0 || comp1) break; else discard_fragment; break;\n"
             "    case 2u: // XOR\n"
-            "      if (comp0 != comp1) break; else discard; break;\n"
+            "      if (comp0 != comp1) break; else discard_fragment; break;\n"
             "    case 3u: // XNOR\n"
-            "      if (comp0 == comp1) break; else discard; break;\n"
+            "      if (comp0 == comp1) break; else discard_fragment; break;\n"
             "    }}\n"
             "  }}\n"
             "\n");