Geometry Nodes: extract mesh surface sampling functions to separate file

1 files changed, 158 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/mesh_sample.cc b/source/blender/blenkernel/intern/mesh_sample.cc
new file mode 100644
index 00000000000..91c9951ae89
--- /dev/null
+++ b/source/blender/blenkernel/intern/mesh_sample.cc
@@ -0,0 +1,158 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "BKE_attribute_math.hh"
+#include "BKE_mesh_runtime.h"
+#include "BKE_mesh_sample.hh"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+namespace blender::bke::mesh_surface_sample {
+
+static Span<MLoopTri> get_mesh_looptris(const Mesh &mesh)
+{
+  /* This only updates a cache and can be considered to be logically const. */
+  const MLoopTri *looptris = BKE_mesh_runtime_looptri_ensure(const_cast<Mesh *>(&mesh));
+  const int looptris_len = BKE_mesh_runtime_looptri_len(&mesh);
+  return {looptris, looptris_len};
+}
+
+template<typename T>
+BLI_NOINLINE static void sample_point_attribute(const Mesh &mesh,
+                                                const Span<int> looptri_indices,
+                                                const Span<float3> bary_coords,
+                                                const VArray<T> &data_in,
+                                                const MutableSpan<T> data_out)
+{
+  const Span<MLoopTri> looptris = get_mesh_looptris(mesh);
+
+  for (const int i : bary_coords.index_range()) {
+    const int looptri_index = looptri_indices[i];
+    const MLoopTri &looptri = looptris[looptri_index];
+    const float3 &bary_coord = bary_coords[i];
+
+    const int v0_index = mesh.mloop[looptri.tri[0]].v;
+    const int v1_index = mesh.mloop[looptri.tri[1]].v;
+    const int v2_index = mesh.mloop[looptri.tri[2]].v;
+
+    const T v0 = data_in[v0_index];
+    const T v1 = data_in[v1_index];
+    const T v2 = data_in[v2_index];
+
+    const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
+    data_out[i] = interpolated_value;
+  }
+}
+
+void sample_point_attribute(const Mesh &mesh,
+                            const Span<int> looptri_indices,
+                            const Span<float3> bary_coords,
+                            const GVArray &data_in,
+                            const GMutableSpan data_out)
+{
+  BLI_assert(data_out.size() == looptri_indices.size());
+  BLI_assert(data_out.size() == bary_coords.size());
+  BLI_assert(data_in.size() == mesh.totvert);
+  BLI_assert(data_in.type() == data_out.type());
+
+  const CPPType &type = data_in.type();
+  attribute_math::convert_to_static_type(type, [&](auto dummy) {
+    using T = decltype(dummy);
+    sample_point_attribute<T>(
+        mesh, looptri_indices, bary_coords, data_in.typed<T>(), data_out.typed<T>());
+  });
+}
+
+template<typename T>
+BLI_NOINLINE static void sample_corner_attribute(const Mesh &mesh,
+                                                 const Span<int> looptri_indices,
+                                                 const Span<float3> bary_coords,
+                                                 const VArray<T> &data_in,
+                                                 const MutableSpan<T> data_out)
+{
+  Span<MLoopTri> looptris = get_mesh_looptris(mesh);
+
+  for (const int i : bary_coords.index_range()) {
+    const int looptri_index = looptri_indices[i];
+    const MLoopTri &looptri = looptris[looptri_index];
+    const float3 &bary_coord = bary_coords[i];
+
+    const int loop_index_0 = looptri.tri[0];
+    const int loop_index_1 = looptri.tri[1];
+    const int loop_index_2 = looptri.tri[2];
+
+    const T v0 = data_in[loop_index_0];
+    const T v1 = data_in[loop_index_1];
+    const T v2 = data_in[loop_index_2];
+
+    const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
+    data_out[i] = interpolated_value;
+  }
+}
+
+void sample_corner_attribute(const Mesh &mesh,
+                             const Span<int> looptri_indices,
+                             const Span<float3> bary_coords,
+                             const GVArray &data_in,
+                             const GMutableSpan data_out)
+{
+  BLI_assert(data_out.size() == looptri_indices.size());
+  BLI_assert(data_out.size() == bary_coords.size());
+  BLI_assert(data_in.size() == mesh.totloop);
+  BLI_assert(data_in.type() == data_out.type());
+
+  const CPPType &type = data_in.type();
+  attribute_math::convert_to_static_type(type, [&](auto dummy) {
+    using T = decltype(dummy);
+    sample_corner_attribute<T>(
+        mesh, looptri_indices, bary_coords, data_in.typed<T>(), data_out.typed<T>());
+  });
+}
+
+template<typename T>
+void sample_face_attribute(const Mesh &mesh,
+                           const Span<int> looptri_indices,
+                           const VArray<T> &data_in,
+                           const MutableSpan<T> data_out)
+{
+  Span<MLoopTri> looptris = get_mesh_looptris(mesh);
+
+  for (const int i : data_out.index_range()) {
+    const int looptri_index = looptri_indices[i];
+    const MLoopTri &looptri = looptris[looptri_index];
+    const int poly_index = looptri.poly;
+    data_out[i] = data_in[poly_index];
+  }
+}
+
+void sample_face_attribute(const Mesh &mesh,
+                           const Span<int> looptri_indices,
+                           const GVArray &data_in,
+                           const GMutableSpan data_out)
+{
+  BLI_assert(data_out.size() == looptri_indices.size());
+  BLI_assert(data_in.size() == mesh.totpoly);
+  BLI_assert(data_in.type() == data_out.type());
+
+  const CPPType &type = data_in.type();
+  attribute_math::convert_to_static_type(type, [&](auto dummy) {
+    using T = decltype(dummy);
+    sample_face_attribute<T>(mesh, looptri_indices, data_in.typed<T>(), data_out.typed<T>());
+  });
+}
+
+}  // namespace blender::bke::mesh_surface_sample