Curves: Support pressure in sculpt brushes

Multiply the radius and strength of sculpt brushes by the pressure
when "use pressure" is turned on. The brush system isn't responsible
for this, so the pressure needs to be stored in `StrokeExtension`.

Differential Revision: https://developer.blender.org/D14996

7 files changed, 40 insertions, 8 deletions

diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_add.cc b/source/blender/editors/sculpt_paint/curves_sculpt_add.cc
index 04ae6c62aee..db9afe878cc 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_add.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_add.cc
@@ -179,7 +179,7 @@ struct AddOperationExecutor {
     curves_sculpt_ = scene_->toolsettings->curves_sculpt;
     brush_ = BKE_paint_brush_for_read(&curves_sculpt_->paint);
     brush_settings_ = brush_->curves_sculpt_settings;
-    brush_radius_re_ = BKE_brush_size_get(scene_, brush_);
+    brush_radius_re_ = brush_radius_get(*scene_, *brush_, stroke_extension);
     brush_pos_re_ = stroke_extension.mouse_position;
 
     use_front_face_ = brush_->flag & BRUSH_FRONTFACE;
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_comb.cc b/source/blender/editors/sculpt_paint/curves_sculpt_comb.cc
index cecb13fbf7f..54a084168cf 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_comb.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_comb.cc
@@ -126,8 +126,8 @@ struct CombOperationExecutor {
 
     curves_sculpt_ = scene_->toolsettings->curves_sculpt;
     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_);
+    brush_radius_re_ = brush_radius_get(*scene_, *brush_, stroke_extension);
+    brush_strength_ = brush_strength_get(*scene_, *brush_, stroke_extension);
 
     curves_to_world_mat_ = object_->obmat;
     world_to_curves_mat_ = curves_to_world_mat_.inverted();
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_delete.cc b/source/blender/editors/sculpt_paint/curves_sculpt_delete.cc
index 9446f38891e..e610e4eeb61 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_delete.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_delete.cc
@@ -99,7 +99,7 @@ struct DeleteOperationExecutor {
 
     curves_sculpt_ = scene_->toolsettings->curves_sculpt;
     brush_ = BKE_paint_brush_for_read(&curves_sculpt_->paint);
-    brush_radius_re_ = BKE_brush_size_get(scene_, brush_);
+    brush_radius_re_ = brush_radius_get(*scene_, *brush_, stroke_extension);
 
     brush_pos_re_ = stroke_extension.mouse_position;
     brush_pos_prev_re_ = stroke_extension.is_first ? stroke_extension.mouse_position :
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc b/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc
index d10cf239dd2..16df721a853 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc
@@ -321,8 +321,8 @@ struct CurvesEffectOperationExecutor {
 
     const CurvesSculpt &curves_sculpt = *scene_->toolsettings->curves_sculpt;
     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_);
+    brush_radius_re_ = brush_radius_get(*scene_, *brush_, stroke_extension);
+    brush_strength_ = brush_strength_get(*scene_, *brush_, stroke_extension);
     brush_radius_sq_re_ = pow2f(brush_radius_re_);
     falloff_shape_ = eBrushFalloffShape(brush_->falloff_shape);
 
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh b/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
index 00e7213b5e6..0af4a608679 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_intern.hh
@@ -24,8 +24,17 @@ using bke::CurvesGeometry;
 struct StrokeExtension {
   bool is_first;
   float2 mouse_position;
+  float pressure;
 };
 
+float brush_radius_get(const Scene &scene,
+                       const Brush &brush,
+                       const StrokeExtension &stroke_extension);
+
+float brush_strength_get(const Scene &scene,
+                         const Brush &brush,
+                         const StrokeExtension &stroke_extension);
+
 /**
  * Base class for stroke based operations in curves sculpt mode.
  */
diff --git a/source/blender/editors/sculpt_paint/curves_sculpt_ops.cc b/source/blender/editors/sculpt_paint/curves_sculpt_ops.cc
index 776da37205c..66e67bd0d06 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_ops.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_ops.cc
@@ -74,6 +74,28 @@ using blender::bke::CurvesGeometry;
 /** \name * SCULPT_CURVES_OT_brush_stroke
  * \{ */
 
+float brush_radius_get(const Scene &scene,
+                       const Brush &brush,
+                       const StrokeExtension &stroke_extension)
+{
+  const float initial_radius = BKE_brush_size_get(&scene, &brush);
+  if (BKE_brush_use_size_pressure(&brush)) {
+    return initial_radius * stroke_extension.pressure;
+  }
+  return initial_radius;
+}
+
+float brush_strength_get(const Scene &scene,
+                         const Brush &brush,
+                         const StrokeExtension &stroke_extension)
+{
+  const float initial_radius = BKE_brush_alpha_get(&scene, &brush);
+  if (BKE_brush_use_alpha_pressure(&brush)) {
+    return initial_radius * stroke_extension.pressure;
+  }
+  return initial_radius;
+}
+
 static std::unique_ptr<CurvesSculptStrokeOperation> start_brush_operation(bContext &C,
                                                                           wmOperator &op)
 {
@@ -128,6 +150,7 @@ static void stroke_update_step(bContext *C,
 
   StrokeExtension stroke_extension;
   RNA_float_get_array(stroke_element, "mouse", stroke_extension.mouse_position);
+  stroke_extension.pressure = RNA_float_get(stroke_element, "pressure");
 
   if (!op_data->operation) {
     stroke_extension.is_first = true;
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 e009b443839..4095c9427e1 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_snake_hook.cc
@@ -112,8 +112,8 @@ struct SnakeHookOperatorExecutor {
 
     curves_sculpt_ = scene_->toolsettings->curves_sculpt;
     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_);
+    brush_radius_re_ = brush_radius_get(*scene_, *brush_, stroke_extension);
+    brush_strength_ = brush_strength_get(*scene_, *brush_, stroke_extension);
     falloff_shape_ = static_cast<eBrushFalloffShape>(brush_->falloff_shape);
 
     curves_to_world_mat_ = object_->obmat;