Autodesk: Add HgiAttachmentResolveFilter for depth texture in HgiMetal

pxr/imaging/hgi/attachmentDesc.cpp

@@ -44,7 +44,8 @@ bool operator==(
             lhs.srcAlphaBlendFactor == rhs.srcAlphaBlendFactor &&
             lhs.dstAlphaBlendFactor == rhs.dstAlphaBlendFactor &&
             lhs.alphaBlendOp == rhs.alphaBlendOp &&
-            lhs.blendConstantColor == rhs.blendConstantColor;
+            lhs.blendConstantColor == rhs.blendConstantColor &&
+            lhs.resolveFilter == rhs.resolveFilter;
 }
 
 bool operator!=(
@@ -72,7 +73,8 @@ std::ostream& operator<<(
         << "srcAlphaBlendFactor: " << attachment.srcAlphaBlendFactor << ", "
         << "dstAlphaBlendFactor: " << attachment.dstAlphaBlendFactor << ", "
         << "alphaBlendOp: " << attachment.alphaBlendOp << ", "
-        << "blendConstantColor: " << attachment.blendConstantColor <<
+        << "blendConstantColor: " << attachment.blendConstantColor << ", "
+        << "resolveFilter: " << attachment.resolveFilter <<
     "}";
     return out;
 }

pxr/imaging/hgi/attachmentDesc.h

@@ -80,6 +80,7 @@ struct HgiAttachmentDesc
     , dstAlphaBlendFactor(HgiBlendFactorZero)
     , alphaBlendOp(HgiBlendOpAdd)
     , blendConstantColor(0.0f, 0.0f, 0.0f, 0.0f)
+    , resolveFilter(HgiAttachmentResolveFilterDefault)
     {}
 
     HgiFormat format;
@@ -96,6 +97,7 @@ struct HgiAttachmentDesc
     HgiBlendFactor dstAlphaBlendFactor;
     HgiBlendOp alphaBlendOp;
     GfVec4f blendConstantColor;
+    HgiAttachmentResolveFilter resolveFilter;
 };
 
 using HgiAttachmentDescVector = std::vector<HgiAttachmentDesc>;

pxr/imaging/hgi/enums.h

@@ -297,6 +297,34 @@ enum HgiAttachmentStoreOp
     HgiAttachmentStoreOpCount
 };
 
+/// \enum HgiAttachmentResolveFilter
+///
+/// Describes what will happen to the attachment pixel data after MSAA resolving.
+///
+/// <ul>
+/// <li>HgiAttachmentResolveFilterDefault:
+///   The attachment pixel value will be determined by the default mode which can vary across different APIs.</li>
+/// <li>HgiAttachmentResolveFilterSample0:
+///   The attachment pixel value will be the value of the first sample.</li>
+/// <li>HgiAttachmentResolveFilterMin:
+///   The attachment pixel value will be the minimum value of all the samples.</li>
+/// <li>HgiAttachmentResolveFilterMax:
+///   The attachment pixel value will be the maximum value of all the samples.</li>
+/// <li>HgiAttachmentResolveFilterAverage:
+///   The attachment pixel value will be the average value of all the samples..</li>
+/// </ul>
+///
+enum HgiAttachmentResolveFilter
+{
+    HgiAttachmentResolveFilterDefault = 0,
+    HgiAttachmentResolveFilterSample0,
+    HgiAttachmentResolveFilterMin,
+    HgiAttachmentResolveFilterMax,
+    HgiAttachmentResolveFilterAverage,
+
+    HgiAttachmentResolveFilterCount
+};
+
 /// \enum HgiBufferUsageBits
 ///
 /// Describes the properties and usage of the buffer.

pxr/imaging/hgiMetal/graphicsCmds.mm

@@ -72,6 +72,19 @@
     }
 }
 
+static MTLMultisampleDepthResolveFilter
+_HgiMultiSampleResolveFilterToMTLMultiSampleDepthResolveFilter(HgiAttachmentResolveFilter filter)
+{
+    if (filter == HgiAttachmentResolveFilterSample0)
+        return MTLMultisampleDepthResolveFilterSample0;
+    else if (filter == HgiAttachmentResolveFilterMin)
+        return MTLMultisampleDepthResolveFilterMin;
+    else if (filter == HgiAttachmentResolveFilterMax)
+        return MTLMultisampleDepthResolveFilterMax;
+    else
+        return MTLMultisampleDepthResolveFilterSample0;
+}
+
 HgiMetalGraphicsCmds::HgiMetalGraphicsCmds(
     HgiMetal* hgi,
     HgiGraphicsCmdsDesc const& desc)
@@ -208,6 +221,12 @@
             metalDepthAttachment.resolveTexture =
                 resolveTexture->GetTextureId();
 
+            if (hgiDepthAttachment.resolveFilter != HgiAttachmentResolveFilterDefault)
+            {
+                metalDepthAttachment.depthResolveFilter = 
+                    _HgiMultiSampleResolveFilterToMTLMultiSampleDepthResolveFilter(hgiDepthAttachment.resolveFilter);
+            }
+
             if (hgiDepthAttachment.storeOp == HgiAttachmentStoreOpStore) {
                 metalDepthAttachment.storeAction =
                     MTLStoreActionStoreAndMultisampleResolve;