1 files changed, 56 insertions, 0 deletions
diff --git a/source/blender/draw/intern/shaders/common_subdiv_normals_accumulate_comp.glsl b/source/blender/draw/intern/shaders/common_subdiv_normals_accumulate_comp.glsl
new file mode 100644
index 00000000000..575090472b1
--- /dev/null
+++ b/source/blender/draw/intern/shaders/common_subdiv_normals_accumulate_comp.glsl
@@ -0,0 +1,56 @@
+
+/* To be compile with common_subdiv_lib.glsl */
+
+layout(std430, binding = 0) readonly buffer inputVertexData
+{
+  PosNorLoop pos_nor[];
+};
+
+layout(std430, binding = 1) readonly buffer faceAdjacencyOffsets
+{
+  uint face_adjacency_offsets[];
+};
+
+layout(std430, binding = 2) readonly buffer faceAdjacencyLists
+{
+  uint face_adjacency_lists[];
+};
+
+layout(std430, binding = 3) writeonly buffer vertexNormals
+{
+  vec3 normals[];
+};
+
+void main()
+{
+  uint vertex_index = get_global_invocation_index();
+  if (vertex_index >= total_dispatch_size) {
+    return;
+  }
+
+  uint first_adjacent_face_offset = face_adjacency_offsets[vertex_index];
+  uint number_of_adjacent_faces = face_adjacency_offsets[vertex_index + 1] -
+                                  first_adjacent_face_offset;
+
+  vec3 accumulated_normal = vec3(0.0);
+
+  /* For each adjacent face. */
+  for (uint i = 0; i < number_of_adjacent_faces; i++) {
+    uint adjacent_face = face_adjacency_lists[first_adjacent_face_offset + i];
+    uint start_loop_index = adjacent_face * 4;
+
+    /* Compute face normal. */
+    vec3 adjacent_verts[3];
+    for (uint j = 0; j < 3; j++) {
+      adjacent_verts[j] = get_vertex_pos(pos_nor[start_loop_index + j]);
+    }
+
+    vec3 face_normal = normalize(
+        cross(adjacent_verts[1] - adjacent_verts[0], adjacent_verts[2] - adjacent_verts[0]));
+    accumulated_normal += face_normal;
+  }
+
+  float weight = 1.0 / float(number_of_adjacent_faces);
+  vec3 normal = normalize(accumulated_normal);
+  normals[vertex_index] = normal;
+}