Curves: Avoid creating types array when unnecessary

When the curve type attribute doesn't exist, there is no reason to
create an array for it only to fill the default value, which will add
overhead to subsequent "add" operations. I added a "get_if_single"
method to virtual array to simplify this check. Also use the existing
functions for filling curve types.

Differential Revision: https://developer.blender.org/D15560

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_virtual_array.hh b/source/blender/blenlib/BLI_virtual_array.hh
index 7eab960b302..00677cf28a2 100644
--- a/source/blender/blenlib/BLI_virtual_array.hh
+++ b/source/blender/blenlib/BLI_virtual_array.hh
@@ -23,6 +23,8 @@
  * see of the increased compile time and binary size is worth it.
  */
 
+#include <optional>
+
 #include "BLI_any.hh"
 #include "BLI_array.hh"
 #include "BLI_index_mask.hh"
@@ -803,6 +805,18 @@ template<typename T> class VArrayCommon {
   }
 
   /**
+   * Return the value that is returned for every index, if the array is stored as a single value.
+   */
+  std::optional<T> get_if_single() const
+  {
+    const CommonVArrayInfo info = impl_->common_info();
+    if (info.type != CommonVArrayInfo::Type::Single) {
+      return std::nullopt;
+    }
+    return *static_cast<const T *>(info.data);
+  }
+
+  /**
    * Return true when the other virtual references the same underlying memory.
    */
   bool is_same(const VArrayCommon<T> &other) const