Curves: new Add brush

This adds a new Add brush for the new curves object type in sculpt mode.
The brush is used to insert new curves (typically hair) on the surface object.

Supported features:
* Add single curve exactly at the cursor position when `Add Amount` is 1.
* Front faces only.
* Independent interpolate shape and interpolate length settings.
* Smooth and flat shading affects curve shape interpolation.
* Spherical and projection brush.

This also adds the `surface_triangle_index` and `surface_triangle_coordinate`
attributes. Those store information about what position on the surface each
added curve is attached to:
* `surface_triangle_index` (`int`): Index of the internal triangle that a curve
  is attached to. `-1` when the curve is not attached to the surface.
* `surface_triangle_coordinate` (`float2`): First two numbers of a barycentric
  coordinate that reference a specific position within the triangle.

Ref T96444.

Differential Revision: https://developer.blender.org/D14340

1 files changed, 29 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_kdopbvh.h b/source/blender/blenlib/BLI_kdopbvh.h
index 5e56eec2ec6..38f3e1ee290 100644
--- a/source/blender/blenlib/BLI_kdopbvh.h
+++ b/source/blender/blenlib/BLI_kdopbvh.h
@@ -324,3 +324,32 @@ extern const float bvhtree_kdop_axes[13][3];
 #ifdef __cplusplus
 }
 #endif
+
+#ifdef __cplusplus
+
+#  include "BLI_function_ref.hh"
+#  include "BLI_math_vector.hh"
+
+namespace blender {
+
+using BVHTree_RangeQuery_CPP = FunctionRef<void(int index, const float3 &co, float dist_sq)>;
+
+inline void BLI_bvhtree_range_query_cpp(BVHTree &tree,
+                                        const float3 co,
+                                        float radius,
+                                        BVHTree_RangeQuery_CPP fn)
+{
+  BLI_bvhtree_range_query(
+      &tree,
+      co,
+      radius,
+      [](void *userdata, const int index, const float co[3], const float dist_sq) {
+        BVHTree_RangeQuery_CPP fn = *static_cast<BVHTree_RangeQuery_CPP *>(userdata);
+        fn(index, co, dist_sq);
+      },
+      &fn);
+}
+
+}  // namespace blender
+
+#endif