1 files changed, 71 insertions, 0 deletions
diff --git a/intern/cycles/hydra/attribute.cpp b/intern/cycles/hydra/attribute.cpp
new file mode 100644
index 00000000000..f22665345e6
--- /dev/null
+++ b/intern/cycles/hydra/attribute.cpp
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright 2022 NVIDIA Corporation
+ * Copyright 2022 Blender Foundation */
+
+#include "hydra/attribute.h"
+#include "scene/attribute.h"
+#include "scene/geometry.h"
+#include "scene/scene.h"
+
+#include <pxr/base/gf/vec2f.h>
+#include <pxr/base/gf/vec3f.h>
+#include <pxr/base/gf/vec4f.h>
+#include <pxr/base/vt/array.h>
+#include <pxr/imaging/hd/tokens.h>
+
+HDCYCLES_NAMESPACE_OPEN_SCOPE
+
+void ApplyPrimvars(AttributeSet &attributes,
+                   const ustring &name,
+                   VtValue value,
+                   AttributeElement elem,
+                   AttributeStandard std)
+{
+  const void *data = HdGetValueData(value);
+  size_t size = value.GetArraySize();
+
+  const HdType valueType = HdGetValueTupleType(value).type;
+
+  TypeDesc attrType = CCL_NS::TypeUnknown;
+  switch (valueType) {
+    case HdTypeFloat:
+      attrType = CCL_NS::TypeFloat;
+      size *= sizeof(float);
+      break;
+    case HdTypeFloatVec2:
+      attrType = CCL_NS::TypeFloat2;
+      size *= sizeof(float2);
+      static_assert(sizeof(GfVec2f) == sizeof(float2));
+      break;
+    case HdTypeFloatVec3: {
+      attrType = CCL_NS::TypeVector;
+      size *= sizeof(float3);
+      // The Cycles "float3" data type is padded to "float4", so need to convert the array
+      const auto &valueData = value.Get<VtVec3fArray>();
+      VtArray<float3> valueConverted;
+      valueConverted.reserve(valueData.size());
+      for (const GfVec3f &vec : valueData) {
+        valueConverted.push_back(make_float3(vec[0], vec[1], vec[2]));
+      }
+      data = valueConverted.data();
+      value = std::move(valueConverted);
+      break;
+    }
+    case HdTypeFloatVec4:
+      attrType = CCL_NS::TypeFloat4;
+      size *= sizeof(float4);
+      static_assert(sizeof(GfVec4f) == sizeof(float4));
+      break;
+    default:
+      TF_WARN("Unsupported attribute type %d", static_cast<int>(valueType));
+      return;
+  }
+
+  Attribute *const attr = attributes.add(name, attrType, elem);
+  attr->std = std;
+
+  assert(size == attr->buffer.size());
+  std::memcpy(attr->data(), data, size);
+}
+
+HDCYCLES_NAMESPACE_CLOSE_SCOPE