Vulkan: Add support for unrestricted depth range.

6 files changed, 35 insertions, 10 deletions

diff --git a/Source/Core/VideoBackends/Vulkan/VKPipeline.cpp b/Source/Core/VideoBackends/Vulkan/VKPipeline.cpp
index be3aae1390..1b8dd0eb9a 100644
--- a/Source/Core/VideoBackends/Vulkan/VKPipeline.cpp
+++ b/Source/Core/VideoBackends/Vulkan/VKPipeline.cpp
@@ -368,12 +368,19 @@ std::unique_ptr<VKPipeline> VKPipeline::Create(const AbstractPipelineConfig& con
       GetVulkanColorBlendState(config.blending_state, blend_attachment_states.data(),
                                static_cast<uint32_t>(blend_attachment_states.size()));
 
+  static const VkDepthClampRangeEXT clamp_range = {0.0f, MAX_EFB_DEPTH};
+  static const VkPipelineViewportDepthClampControlCreateInfoEXT depth_clamp_state = {
+      VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_DEPTH_CLAMP_CONTROL_CREATE_INFO_EXT, nullptr,
+      VK_DEPTH_CLAMP_MODE_USER_DEFINED_RANGE_EXT,  // VkDepthClampModeEXT            depthClampMode
+      &clamp_range  // const VkDepthClampRangeEXT*    pDepthClampRange
+  };
+
   // This viewport isn't used, but needs to be specified anyway.
   static const VkViewport viewport = {0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f};
   static const VkRect2D scissor = {{0, 0}, {1, 1}};
   static const VkPipelineViewportStateCreateInfo viewport_state = {
       VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO,
-      nullptr,
+      &depth_clamp_state,
       0,          // VkPipelineViewportStateCreateFlags    flags;
       1,          // uint32_t                              viewportCount
       &viewport,  // const VkViewport*                     pViewports
diff --git a/Source/Core/VideoBackends/Vulkan/VulkanContext.cpp b/Source/Core/VideoBackends/Vulkan/VulkanContext.cpp
index c6ff5e148d..60580aff40 100644
--- a/Source/Core/VideoBackends/Vulkan/VulkanContext.cpp
+++ b/Source/Core/VideoBackends/Vulkan/VulkanContext.cpp
@@ -459,6 +459,7 @@ void VulkanContext::PopulateBackendInfo(BackendInfo* backend_info)
   backend_info->bSupportsDynamicVertexLoader = true;        // Assumed support.
   backend_info->bSupportsVSLinePointExpand = true;          // Assumed support.
   backend_info->bSupportsHDROutput = true;                  // Assumed support.
+  backend_info->bSupportsUnrestrictedDepthRange = false;    // Dependent on features.
 }
 
 void VulkanContext::PopulateBackendInfoAdapters(BackendInfo* backend_info, const GPUList& gpu_list)
@@ -663,6 +664,16 @@ bool VulkanContext::SelectDeviceExtensions(bool enable_surface)
   AddExtension(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME, false);
   AddExtension(VK_EXT_MEMORY_BUDGET_EXTENSION_NAME, false);
 
+  if (!DriverDetails::HasBug(DriverDetails::BUG_BROKEN_D32F_CLEAR))
+  {
+    // Unrestricted depth range is one of the few extensions that changes the behavior
+    // of Vulkan just by being enabled, so we rely on lazy evaluation to ensure it is
+    // not enabled unless depth clamp control is supported.
+    g_backend_info.bSupportsUnrestrictedDepthRange =
+        AddExtension(VK_EXT_DEPTH_CLAMP_CONTROL_EXTENSION_NAME, false) &&
+        AddExtension(VK_EXT_DEPTH_RANGE_UNRESTRICTED_EXTENSION_NAME, false);
+  }
+
   return true;
 }
 
diff --git a/Source/Core/VideoCommon/BPFunctions.cpp b/Source/Core/VideoCommon/BPFunctions.cpp
index 0b20bcfd8a..444b1dbc4f 100644
--- a/Source/Core/VideoCommon/BPFunctions.cpp
+++ b/Source/Core/VideoCommon/BPFunctions.cpp
@@ -216,17 +216,12 @@ void SetScissorAndViewport()
     height *= -1;
   }
 
-  // The maximum depth that is written to the depth buffer should never exceed this value.
-  // This is necessary because we use a 2^24 divisor for all our depth values to prevent
-  // floating-point round-trip errors. However the console GPU doesn't ever write a value
-  // to the depth buffer that exceeds 2^24 - 1.
-  constexpr float GX_MAX_DEPTH = 16777215.0f / 16777216.0f;
   if (!g_backend_info.bSupportsDepthClamp)
   {
     // There's no way to support oversized depth ranges in this situation. Let's just clamp the
     // range to the maximum value supported by the console GPU and hope for the best.
-    min_depth = std::clamp(min_depth, 0.0f, GX_MAX_DEPTH);
-    max_depth = std::clamp(max_depth, 0.0f, GX_MAX_DEPTH);
+    min_depth = std::clamp(min_depth, 0.0f, MAX_EFB_DEPTH);
+    max_depth = std::clamp(max_depth, 0.0f, MAX_EFB_DEPTH);
   }
 
   if (VertexShaderManager::UseVertexDepthRange())
@@ -235,13 +230,13 @@ void SetScissorAndViewport()
     // Taking into account whether the depth range is inverted or not.
     if (xfmem.viewport.zRange < 0.0f && g_backend_info.bSupportsReversedDepthRange)
     {
-      min_depth = GX_MAX_DEPTH;
+      min_depth = MAX_EFB_DEPTH;
       max_depth = 0.0f;
     }
     else
     {
       min_depth = 0.0f;
-      max_depth = GX_MAX_DEPTH;
+      max_depth = MAX_EFB_DEPTH;
     }
   }
 
diff --git a/Source/Core/VideoCommon/VertexShaderManager.cpp b/Source/Core/VideoCommon/VertexShaderManager.cpp
index 976cff00f6..4dba5432bc 100644
--- a/Source/Core/VideoCommon/VertexShaderManager.cpp
+++ b/Source/Core/VideoCommon/VertexShaderManager.cpp
@@ -131,6 +131,11 @@ void VertexShaderManager::SetProjectionMatrix(XFStateManager& xf_state_manager)
 
 bool VertexShaderManager::UseVertexDepthRange()
 {
+  // Backend has full support for unrestricted depth ranges including the ability to clamp the
+  // final depth value to MAX_EFB_DEPTH.
+  if (g_backend_info.bSupportsUnrestrictedDepthRange)
+    return false;
+
   // We can't compute the depth range in the vertex shader if we don't support depth clamp.
   if (!g_backend_info.bSupportsDepthClamp)
     return false;
diff --git a/Source/Core/VideoCommon/VideoCommon.h b/Source/Core/VideoCommon/VideoCommon.h
index 517e8b3e9b..abc79a847d 100644
--- a/Source/Core/VideoCommon/VideoCommon.h
+++ b/Source/Core/VideoCommon/VideoCommon.h
@@ -15,6 +15,12 @@
 constexpr u32 EFB_WIDTH = 640u;
 constexpr u32 EFB_HEIGHT = 528u;
 
+// The maximum depth that is written to the depth buffer should never exceed this value.
+// This is necessary because we use a 2^24 divisor for all our depth values to prevent
+// floating-point round-trip errors. However the console GPU doesn't ever write a value
+// to the depth buffer that exceeds 2^24 - 1.
+constexpr float MAX_EFB_DEPTH = 16777215.0f / 16777216.0f;
+
 // Max XFB width is 720. You can only copy out 640 wide areas of efb to XFB
 // so you need multiple copies to do the full width.
 // The VI can do horizontal scaling (TODO: emulate).
diff --git a/Source/Core/VideoCommon/VideoConfig.h b/Source/Core/VideoCommon/VideoConfig.h
index a268278eca..a0baaa666c 100644
--- a/Source/Core/VideoCommon/VideoConfig.h
+++ b/Source/Core/VideoCommon/VideoConfig.h
@@ -180,6 +180,7 @@ struct BackendInfo
   bool bSupportsVSLinePointExpand = false;
   bool bSupportsGLLayerInFS = true;
   bool bSupportsHDROutput = false;
+  bool bSupportsUnrestrictedDepthRange = false;
 };
 
 extern BackendInfo g_backend_info;