Workspaces: Store an active view-layer per scene

Instead of storing a single active view-layer in the workspace, one is
stored for each scene the workspace showed before.
With this, some things become possible:
* Multiple windows in the same workspace but showing different scenes.
* Toggling back and forth scene keeps same active view-layer for each scene.
* Activating workspace which didn't show current scene before, the current view-layer is kept.

A necessary evil for this is that accessing view-layer and object mode
from .py can't be done via workspace directly anymore. It has to be done
through the window, so RNA can use the correct scene.
So instead of `workspace.view_layer`, it's `window.view_layer` now (same
with mode) even though it's still workspace data.

Fixes T53432.

1 files changed, 11 insertions, 6 deletions

diff --git a/source/blender/editors/scene/scene_edit.c b/source/blender/editors/scene/scene_edit.c
index c7f04a0e2f9..812f9a736bf 100644
--- a/source/blender/editors/scene/scene_edit.c
+++ b/source/blender/editors/scene/scene_edit.c
@@ -118,16 +118,20 @@ void ED_scene_exit(bContext *C)
 	ED_object_editmode_exit(C, EM_FREEDATA | EM_DO_UNDO);
 }
 
+static ViewLayer *scene_change_get_new_view_layer(const WorkSpace *workspace, const Scene *scene_new)
+{
+	ViewLayer *layer_new = BKE_workspace_view_layer_get(workspace, scene_new);
+	return layer_new ? layer_new : BKE_view_layer_from_scene_get(scene_new);
+}
+
 void ED_scene_changed_update(Main *bmain, bContext *C, Scene *scene_new, const bScreen *active_screen)
 {
-	/* XXX Just using active scene render-layer for workspace when switching,
-	 * but workspace should remember the last one set. Could store render-layer
-	 * per window-workspace combination (using WorkSpaceDataRelation) */
-	ViewLayer *layer_new = BLI_findlink(&scene_new->view_layers, scene_new->active_view_layer);
+	WorkSpace *workspace = CTX_wm_workspace(C);
+	ViewLayer *layer_new = scene_change_get_new_view_layer(workspace, scene_new);
 	Depsgraph *depsgraph = BKE_scene_get_depsgraph(scene_new, layer_new, true);
 
 	CTX_data_scene_set(C, scene_new);
-	BKE_workspace_view_layer_set(CTX_wm_workspace(C), layer_new);
+	BKE_workspace_view_layer_set(workspace, layer_new, scene_new);
 	BKE_scene_set_background(bmain, scene_new);
 	DEG_graph_relations_update(depsgraph, bmain, scene_new, layer_new);
 	DEG_on_visible_update(bmain, false);
@@ -186,7 +190,8 @@ bool ED_scene_view_layer_delete(
 	BLI_assert(BLI_listbase_is_empty(&scene->view_layers) == false);
 	scene->active_view_layer = 0;
 
-	ED_workspace_view_layer_unset(bmain, layer, scene->view_layers.first);
+	ED_workspace_view_layer_unset(bmain, scene, layer, scene->view_layers.first);
+	BKE_workspace_view_layer_remove_references(bmain, layer);
 	view_layer_remove_unset_nodetrees(bmain, scene, layer);
 
 	BKE_view_layer_free(layer);