corner_verts span is empty when occlusion is enabled. So assign value to it in `SCULPT_vertex_is_occluded` Pull Request: https://projects.blender.org/blender/blender/pulls/121071
corner_verts span is empty when occlusion is enabled. So assign value to it in `SCULPT_vertex_is_occluded` Pull Request: https://projects.blender.org/blender/blender/pulls/121071