Cleanup: Use const in curves sculpt code

This makes it much clearer what data is supposed to be modified
and what data is just used to influence the operation. The new
`BKE_paint_brush_for_read` function isn't great design, but it
can be removed or renamed if similar changes are applied to
more places.

Also pass pointers explicitly to `sample_curves_3d_brush` rather
than reusing the `bContext`. This makes it clearer what data the
function actually needs.

Differential Revision: https://developer.blender.org/D14967

1 files changed, 22 insertions, 18 deletions

diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc b/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc
index 973751e9045..e009b443839 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc
@@ -63,7 +63,7 @@ class SnakeHookOperation : public CurvesSculptStrokeOperation {
   friend struct SnakeHookOperatorExecutor;
 
  public:
-  void on_stroke_extended(bContext *C, const StrokeExtension &stroke_extension) override;
+  void on_stroke_extended(const bContext &C, const StrokeExtension &stroke_extension) override;
 };
 
 /**
@@ -72,19 +72,19 @@ class SnakeHookOperation : public CurvesSculptStrokeOperation {
  */
 struct SnakeHookOperatorExecutor {
   SnakeHookOperation *self_ = nullptr;
-  bContext *C_ = nullptr;
-  Scene *scene_ = nullptr;
-  Object *object_ = nullptr;
+  const Depsgraph *depsgraph_ = nullptr;
+  const Scene *scene_ = nullptr;
   ARegion *region_ = nullptr;
-  View3D *v3d_ = nullptr;
-  RegionView3D *rv3d_ = nullptr;
+  const View3D *v3d_ = nullptr;
+  const RegionView3D *rv3d_ = nullptr;
 
-  CurvesSculpt *curves_sculpt_ = nullptr;
-  Brush *brush_ = nullptr;
+  const CurvesSculpt *curves_sculpt_ = nullptr;
+  const Brush *brush_ = nullptr;
   float brush_radius_re_;
   float brush_strength_;
   eBrushFalloffShape falloff_shape_;
 
+  Object *object_ = nullptr;
   Curves *curves_id_ = nullptr;
   CurvesGeometry *curves_ = nullptr;
 
@@ -95,20 +95,23 @@ struct SnakeHookOperatorExecutor {
   float2 brush_pos_re_;
   float2 brush_pos_diff_re_;
 
-  void execute(SnakeHookOperation &self, bContext *C, const StrokeExtension &stroke_extension)
+  void execute(SnakeHookOperation &self,
+               const bContext &C,
+               const StrokeExtension &stroke_extension)
   {
     BLI_SCOPED_DEFER([&]() { self.last_mouse_position_re_ = stroke_extension.mouse_position; });
 
     self_ = &self;
-    C_ = C;
-    scene_ = CTX_data_scene(C);
-    object_ = CTX_data_active_object(C);
-    region_ = CTX_wm_region(C);
-    v3d_ = CTX_wm_view3d(C);
-    rv3d_ = CTX_wm_region_view3d(C);
+    depsgraph_ = CTX_data_depsgraph_pointer(&C);
+    scene_ = CTX_data_scene(&C);
+    scene_ = CTX_data_scene(&C);
+    object_ = CTX_data_active_object(&C);
+    region_ = CTX_wm_region(&C);
+    v3d_ = CTX_wm_view3d(&C);
+    rv3d_ = CTX_wm_region_view3d(&C);
 
     curves_sculpt_ = scene_->toolsettings->curves_sculpt;
-    brush_ = BKE_paint_brush(&curves_sculpt_->paint);
+    brush_ = BKE_paint_brush_for_read(&curves_sculpt_->paint);
     brush_radius_re_ = BKE_brush_size_get(scene_, brush_);
     brush_strength_ = BKE_brush_alpha_get(scene_, brush_);
     falloff_shape_ = static_cast<eBrushFalloffShape>(brush_->falloff_shape);
@@ -129,7 +132,7 @@ struct SnakeHookOperatorExecutor {
     if (stroke_extension.is_first) {
       if (falloff_shape_ == PAINT_FALLOFF_SHAPE_SPHERE) {
         std::optional<CurvesBrush3D> brush_3d = sample_curves_3d_brush(
-            *C_, *object_, brush_pos_re_, brush_radius_re_);
+            *depsgraph_, *region_, *v3d_, *rv3d_, *object_, brush_pos_re_, brush_radius_re_);
         if (brush_3d.has_value()) {
           self_->brush_3d_ = *brush_3d;
         }
@@ -295,7 +298,8 @@ struct SnakeHookOperatorExecutor {
   }
 };
 
-void SnakeHookOperation::on_stroke_extended(bContext *C, const StrokeExtension &stroke_extension)
+void SnakeHookOperation::on_stroke_extended(const bContext &C,
+                                            const StrokeExtension &stroke_extension)
 {
   SnakeHookOperatorExecutor executor;
   executor.execute(*this, C, stroke_extension);