Fix T96356: artefacts with GPU subdivision and vertex paint mask

The lines paint mask IBO extraction was not implemented for GPU subdivision.
For it to work, we also now need to preserve the subdivision loop to
subdivision edge map, which until now was overwritten to store coarse edges
(the map to coarse edges is still preserved).

Also the paint flag stored in the 4th dimension of the loop normal buffer
was not properly set for flat shaded faces, leading to other kind of
artefacts and render issues.

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh.cc b/source/blender/draw/intern/draw_cache_extract_mesh.cc
index e84f2c7a327..717ea00fc0c 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh.cc
+++ b/source/blender/draw/intern/draw_cache_extract_mesh.cc
@@ -842,6 +842,7 @@ static void mesh_buffer_cache_create_requested_subdiv(MeshBatchCache *cache,
   EXTRACT_ADD_REQUESTED(vbo, tan);
   EXTRACT_ADD_REQUESTED(vbo, edituv_stretch_area);
   EXTRACT_ADD_REQUESTED(vbo, edituv_stretch_angle);
+  EXTRACT_ADD_REQUESTED(ibo, lines_paint_mask);
   EXTRACT_ADD_REQUESTED(ibo, lines_adjacency);
   EXTRACT_ADD_REQUESTED(vbo, vcol);
   EXTRACT_ADD_REQUESTED(vbo, weights);