1 files changed, 37 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_MaskOperation.cc b/source/blender/compositor/operations/COM_MaskOperation.cc
index c7763f08e71..84992f23924 100644
--- a/source/blender/compositor/operations/COM_MaskOperation.cc
+++ b/source/blender/compositor/operations/COM_MaskOperation.cc
@@ -161,4 +161,41 @@ void MaskOperation::executePixelSampled(float output[4],
   }
 }
 
+void MaskOperation::update_memory_buffer_partial(MemoryBuffer *output,
+                                                 const rcti &area,
+                                                 Span<MemoryBuffer *> UNUSED(inputs))
+{
+  Vector<MaskRasterHandle *> handles = get_non_null_handles();
+  if (handles.size() == 0) {
+    output->fill(area, COM_VALUE_ZERO);
+    return;
+  }
+
+  float xy[2];
+  for (BuffersIterator<float> it = output->iterate_with({}, area); !it.is_end(); ++it) {
+    xy[0] = it.x * m_maskWidthInv + m_mask_px_ofs[0];
+    xy[1] = it.y * m_maskHeightInv + m_mask_px_ofs[1];
+    *it.out = 0.0f;
+    for (MaskRasterHandle *handle : handles) {
+      *it.out += BKE_maskrasterize_handle_sample(handle, xy);
+    }
+
+    /* Until we get better falloff. */
+    *it.out /= m_rasterMaskHandleTot;
+  }
+}
+
+Vector<MaskRasterHandle *> MaskOperation::get_non_null_handles() const
+{
+  Vector<MaskRasterHandle *> handles;
+  for (int i = 0; i < m_rasterMaskHandleTot; i++) {
+    MaskRasterHandle *handle = m_rasterMaskHandles[i];
+    if (handle == nullptr) {
+      continue;
+    }
+    handles.append(handle);
+  }
+  return handles;
+}
+
 }  // namespace blender::compositor