Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/subd/osd.h

@@ -0,0 +1,104 @@
+/* SPDX-FileCopyrightText: 2011-2024 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#pragma once
+
+#ifdef WITH_OPENSUBDIV
+
+/* OpenSubdiv headers use M_PI. */
+#  if defined(_MSC_VER) && !defined(_USE_MATH_DEFINES)
+#    define _USE_MATH_DEFINES
+#  endif
+
+#  include <opensubdiv/far/patchMap.h>
+#  include <opensubdiv/far/patchTableFactory.h>
+#  include <opensubdiv/far/primvarRefiner.h>
+#  include <opensubdiv/far/topologyRefinerFactory.h>
+
+#  include "subd/patch.h"
+
+#  include "util/types.h"
+#  include "util/unique_ptr.h"
+#  include "util/vector.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Directly use some OpenSubdiv namespaces for brevity. */
+namespace Far = OpenSubdiv::Far;
+namespace Sdc = OpenSubdiv::Sdc;
+
+class Attribute;
+class Mesh;
+
+/* OpenSubdiv interface for vertex and attribute values. */
+
+template<typename T> struct OsdValue {
+  T value;
+
+  OsdValue() = default;
+
+  void Clear(void *unused = nullptr)
+  {
+    (void)unused;
+    memset((void *)&value, 0, sizeof(T));
+  }
+
+  void AddWithWeight(OsdValue<T> const &src, float weight)
+  {
+    if constexpr (std::is_same_v<T, packed_float3>) {
+      value = float3(value) + float3(src.value) * weight;
+    }
+    else {
+      value += src.value * weight;
+    }
+  }
+};
+
+/* Wrapper around Mesh for TopologyRefinerFactory. */
+
+class OsdMesh {
+ public:
+  /* Face-varying attribute that requires merging of corners with the same value, typically a UV
+   * map. The resulting topology after merging is stored in a topology refiner fvar channel. The
+   * merged attribute values are stored here, in a generic buffer used for different data types. */
+  struct MergedFVar {
+    const Attribute &attr;
+    int channel = -1;
+    vector<char> values;
+  };
+
+  Mesh &mesh;
+  vector<MergedFVar> merged_fvars;
+
+  explicit OsdMesh(Mesh &mesh) : mesh(mesh) {}
+
+  Sdc::Options sdc_options();
+  bool use_smooth_fvar(const Attribute &attr) const;
+  bool use_smooth_fvar() const;
+};
+
+/* OpenSubdiv refiner and patch data structures. */
+
+struct OsdData {
+  unique_ptr<Far::TopologyRefiner> refiner;
+  unique_ptr<Far::PatchTable> patch_table;
+  unique_ptr<Far::PatchMap> patch_map;
+  vector<OsdValue<packed_float3>> refined_verts;
+
+  void build(OsdMesh &osd_mesh);
+};
+
+/* Patch with OpenSubdiv evaluation. */
+
+struct OsdPatch final : Patch {
+  OsdData &osd_data;
+
+  explicit OsdPatch(OsdData &data) : osd_data(data) {}
+  void eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, const float u, const float v)
+      const override;
+};
+
+CCL_NAMESPACE_END
+
+#endif