quickpatch.diff

diff --git a/spine-lua/Animation.lua b/spine-lua/Animation.lua
index 8b4cc42..f4613c1 100644
--- a/spine-lua/Animation.lua
+++ b/spine-lua/Animation.lua
@@ -653,8 +653,8 @@ function Animation.FfdTimeline.new ()
                        end
                else
                        for i = 1, vertexCount do
-                               local prev = prevVertices[i]
-                               vertices[i] = prev + (nextVertices[i] - prev) * percent
+                               local prev = (prevVertices[i] or 0)
+                               vertices[i] = prev + ((nextVertices[i] or 0) - prev) * percent
                        end
                end
        end