GPU subdiv: fix hidden faces in paint mode when hidden in edit mode

Pass `use_hide` to the compute shaders so that we can override the
hidden face flags, like CPU extraction is doing.

source/blender/draw/intern/draw_cache_impl_subdivision.cc

@@ -1205,7 +1205,7 @@ struct DRWSubdivUboStorage {
   uint total_dispatch_size;
 
   int is_edit_mode;
-  int _pad2;
+  int use_hide;
   int _pad3;
 };
 
@@ -1237,6 +1237,7 @@ static void draw_subdiv_init_ubo_storage(const DRWSubdivCache *cache,
   ubo->coarse_face_loopstart_mask = SUBDIV_COARSE_FACE_LOOP_START_MASK;
   ubo->total_dispatch_size = total_dispatch_size;
   ubo->is_edit_mode = cache->is_edit_mode;
+  ubo->use_hide = cache->use_hide;
 }
 
 static void draw_subdiv_ubo_update_and_bind(const DRWSubdivCache *cache,
@@ -2084,6 +2085,7 @@ static bool draw_subdiv_create_requested_buffers(Object *ob,
   MeshRenderData *mr = mesh_render_data_create(
       ob, mesh, is_editmode, is_paint_mode, is_mode_active, obmat, do_final, do_uvedit, ts);
   mr->use_hide = use_hide;
+  draw_cache->use_hide = use_hide;
 
   /* Used for setting loop normals flags. Mapped extraction is only used during edit mode.
    * See comments in #extract_lnor_iter_poly_mesh.

source/blender/draw/intern/draw_subdivision.h

@@ -180,6 +180,7 @@ typedef struct DRWSubdivCache {
 
   /* Extra flags, passed to the UBO. */
   bool is_edit_mode;
+  bool use_hide;
 } DRWSubdivCache;
 
 /* Only frees the data of the cache, caller is responsible to free the cache itself if necessary.

source/blender/draw/intern/shaders/common_subdiv_ibo_lines_comp.glsl

@@ -35,7 +35,7 @@ void emit_line(uint line_offset, uint quad_index, uint start_loop_index, uint co
   uint coarse_quad_index = coarse_polygon_index_from_subdiv_quad_index(quad_index,
                                                                        coarse_poly_count);
 
-  if (is_face_hidden(coarse_quad_index) ||
+  if (use_hide && is_face_hidden(coarse_quad_index) ||
       (input_origindex[vertex_index] == ORIGINDEX_NONE && optimal_display)) {
     output_lines[line_offset + 0] = 0xffffffff;
     output_lines[line_offset + 1] = 0xffffffff;

source/blender/draw/intern/shaders/common_subdiv_ibo_tris_comp.glsl

@@ -45,7 +45,7 @@ void main()
   int triangle_loop_index = (int(quad_index) + mat_offset) * 6;
 #endif
 
-  if (is_face_hidden(coarse_quad_index)) {
+  if (use_hide && is_face_hidden(coarse_quad_index)) {
     output_tris[triangle_loop_index + 0] = 0xffffffff;
     output_tris[triangle_loop_index + 1] = 0xffffffff;
     output_tris[triangle_loop_index + 2] = 0xffffffff;

source/blender/draw/intern/shaders/common_subdiv_lib.glsl

@@ -38,6 +38,8 @@ layout(std140) uniform shader_data
   uint total_dispatch_size;
 
   bool is_edit_mode;
+
+  bool use_hide;
 };
 
 uint get_global_invocation_index()

source/blender/draw/intern/shaders/common_subdiv_patch_evaluation_comp.glsl

@@ -427,7 +427,7 @@ void main()
   output_nors[coarse_quad_index] = fnor;
 #  endif
 
-  if (is_face_hidden(coarse_quad_index)) {
+  if (use_hide && is_face_hidden(coarse_quad_index)) {
     output_indices[coarse_quad_index] = 0xffffffff;
   }
   else {