Fix: Sample pressure properly for 3D curves sculpt brushes

For the "Sphere" 3D brushes, the depth and radius are only sampled at
the beginning of the stroke. This didn't work when tablet pressure is
used as a factor for the brush radius. Now the 3D brush depth is found
with the max radius (as if the pressure was 1.0), but the pressure
factor is used afterwards.

Restructuring the way the brush executors stored the radius made
the change a bit clearer, which is where most of the diff comes from.

Differential Revision: https://developer.blender.org/D15002

1 files changed, 15 insertions, 8 deletions

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 c864fb0c59f..b0a6d6ef29c 100644
--- a/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc
+++ b/source/blender/editors/sculpt_paint/curves_sculpt_grow_shrink.cc
@@ -283,9 +283,10 @@ struct CurvesEffectOperationExecutor {
   CurvesGeometry *curves_ = nullptr;
 
   const Brush *brush_ = nullptr;
-  float brush_radius_re_;
-  float brush_radius_sq_re_;
+  float brush_radius_base_re_;
+  float brush_radius_factor_;
   float brush_strength_;
+
   eBrushFalloffShape falloff_shape_;
 
   float4x4 curves_to_world_mat_;
@@ -321,9 +322,12 @@ struct CurvesEffectOperationExecutor {
 
     const CurvesSculpt &curves_sculpt = *scene_->toolsettings->curves_sculpt;
     brush_ = BKE_paint_brush_for_read(&curves_sculpt.paint);
-    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_);
+
+    brush_radius_base_re_ = BKE_brush_size_get(scene_, brush_);
+    brush_radius_factor_ = brush_radius_factor(*brush_, stroke_extension);
+    brush_strength_ = brush_strength_get(*scene_, *brush_, stroke_extension);
+
     falloff_shape_ = eBrushFalloffShape(brush_->falloff_shape);
 
     curves_to_world_mat_ = object_->obmat;
@@ -341,7 +345,7 @@ struct CurvesEffectOperationExecutor {
                 *rv3d_,
                 *object_,
                 stroke_extension.mouse_position,
-                brush_radius_re_)) {
+                brush_radius_base_re_)) {
           self.brush_3d_ = *brush_3d;
         }
       }
@@ -385,6 +389,9 @@ struct CurvesEffectOperationExecutor {
       symmetry_brush_transforms_inv.append(brush_transform.inverted());
     }
 
+    const float brush_radius_re = brush_radius_base_re_ * brush_radius_factor_;
+    const float brush_radius_sq_re = pow2f(brush_radius_re);
+
     threading::parallel_for(curves_->curves_range(), 256, [&](const IndexRange curves_range) {
       Influences &local_influences = influences_for_thread.local();
 
@@ -414,13 +421,13 @@ struct CurvesEffectOperationExecutor {
                                                                  p1_re,
                                                                  p2_re);
 
-            if (dist_to_brush_sq_re > brush_radius_sq_re_) {
+            if (dist_to_brush_sq_re > brush_radius_sq_re) {
               continue;
             }
 
             const float dist_to_brush_re = std::sqrt(dist_to_brush_sq_re);
             const float radius_falloff = BKE_brush_curve_strength(
-                brush_, dist_to_brush_re, brush_radius_re_);
+                brush_, dist_to_brush_re, brush_radius_re);
             const float weight = brush_strength_ * radius_falloff;
 
             const float3 closest_on_segment_cu = math::interpolate(
@@ -473,7 +480,7 @@ struct CurvesEffectOperationExecutor {
     const float3 brush_pos_end_cu = world_to_curves_mat_ * brush_pos_end_wo;
     const float3 brush_pos_diff_cu = brush_pos_end_cu - brush_pos_start_cu;
     const float brush_pos_diff_length_cu = math::length(brush_pos_diff_cu);
-    const float brush_radius_cu = self_->brush_3d_.radius_cu;
+    const float brush_radius_cu = self_->brush_3d_.radius_cu * brush_radius_factor_;
     const float brush_radius_sq_cu = pow2f(brush_radius_cu);
 
     const Vector<float4x4> symmetry_brush_transforms = get_symmetry_brush_transforms(