Cleanup: Use const mesh to ensure BVH and triangulation cache

As noted in a comment now, these functions only update a cache, so they
don't change the logical state of the mesh, which is "it will have the
data when necessary." Using a const argument will help const correctness
when accessing an object's evaluated mesh.

4 files changed, 13 insertions, 6 deletions

diff --git a/source/blender/blenkernel/BKE_bvhutils.h b/source/blender/blenkernel/BKE_bvhutils.h
index 78908908343..8be2fcbdb83 100644
--- a/source/blender/blenkernel/BKE_bvhutils.h
+++ b/source/blender/blenkernel/BKE_bvhutils.h
@@ -218,7 +218,7 @@ BVHTree *bvhtree_from_mesh_looptri_ex(struct BVHTreeFromMesh *data,
                                       ThreadMutex *mesh_eval_mutex);
 
 BVHTree *BKE_bvhtree_from_mesh_get(struct BVHTreeFromMesh *data,
-                                   struct Mesh *mesh,
+                                   const struct Mesh *mesh,
                                    const BVHCacheType bvh_cache_type,
                                    const int tree_type);
 
diff --git a/source/blender/blenkernel/BKE_mesh_runtime.h b/source/blender/blenkernel/BKE_mesh_runtime.h
index 67c87e96aff..3efbef94081 100644
--- a/source/blender/blenkernel/BKE_mesh_runtime.h
+++ b/source/blender/blenkernel/BKE_mesh_runtime.h
@@ -45,7 +45,7 @@ void BKE_mesh_runtime_reset(struct Mesh *mesh);
 void BKE_mesh_runtime_reset_on_copy(struct Mesh *mesh, const int flag);
 int BKE_mesh_runtime_looptri_len(const struct Mesh *mesh);
 void BKE_mesh_runtime_looptri_recalc(struct Mesh *mesh);
-const struct MLoopTri *BKE_mesh_runtime_looptri_ensure(struct Mesh *mesh);
+const struct MLoopTri *BKE_mesh_runtime_looptri_ensure(const struct Mesh *mesh);
 bool BKE_mesh_runtime_ensure_edit_data(struct Mesh *mesh);
 bool BKE_mesh_runtime_clear_edit_data(struct Mesh *mesh);
 bool BKE_mesh_runtime_reset_edit_data(struct Mesh *mesh);
diff --git a/source/blender/blenkernel/intern/bvhutils.cc b/source/blender/blenkernel/intern/bvhutils.cc
index c2852426174..3dea49d1953 100644
--- a/source/blender/blenkernel/intern/bvhutils.cc
+++ b/source/blender/blenkernel/intern/bvhutils.cc
@@ -1438,9 +1438,12 @@ static BLI_bitmap *looptri_no_hidden_map_get(const MPoly *mpoly,
 
 /**
  * Builds or queries a bvhcache for the cache bvhtree of the request type.
+ *
+ * \note This function only fills a cache, and therefore the mesh argument can
+ * be considered logically const. Concurrent access is protected by a mutex.
  */
 BVHTree *BKE_bvhtree_from_mesh_get(struct BVHTreeFromMesh *data,
-                                   struct Mesh *mesh,
+                                   const struct Mesh *mesh,
                                    const BVHCacheType bvh_cache_type,
                                    const int tree_type)
 {
@@ -1448,7 +1451,7 @@ BVHTree *BKE_bvhtree_from_mesh_get(struct BVHTreeFromMesh *data,
   BVHCache **bvh_cache_p = (BVHCache **)&mesh->runtime.bvh_cache;
   ThreadMutex *mesh_eval_mutex = (ThreadMutex *)mesh->runtime.eval_mutex;
 
-  bool is_cached = bvhcache_find(bvh_cache_p, bvh_cache_type, &tree, nullptr, nullptr);
+  const bool is_cached = bvhcache_find(bvh_cache_p, bvh_cache_type, &tree, nullptr, nullptr);
 
   if (is_cached && tree == nullptr) {
     memset(data, 0, sizeof(*data));
diff --git a/source/blender/blenkernel/intern/mesh_runtime.c b/source/blender/blenkernel/intern/mesh_runtime.c
index 011dd7e25ee..6ae534012a9 100644
--- a/source/blender/blenkernel/intern/mesh_runtime.c
+++ b/source/blender/blenkernel/intern/mesh_runtime.c
@@ -158,8 +158,12 @@ static void mesh_runtime_looptri_recalc_isolated(void *userdata)
   BKE_mesh_runtime_looptri_recalc(mesh);
 }
 
-/* This is a ported copy of dm_getLoopTriArray(dm). */
-const MLoopTri *BKE_mesh_runtime_looptri_ensure(Mesh *mesh)
+/**
+ * \note This function only fills a cache, and therefore the mesh argument can
+ * be considered logically const. Concurrent access is protected by a mutex.
+ * \note This is a ported copy of dm_getLoopTriArray(dm).
+ */
+const MLoopTri *BKE_mesh_runtime_looptri_ensure(const Mesh *mesh)
 {
   ThreadMutex *mesh_eval_mutex = (ThreadMutex *)mesh->runtime.eval_mutex;
   BLI_mutex_lock(mesh_eval_mutex);