diff --git a/Source/Scene/PostProcessStageTextureCache.js b/Source/Scene/PostProcessStageTextureCache.js
index c3a57eafa7e4..35879037d134 100644
--- a/Source/Scene/PostProcessStageTextureCache.js
+++ b/Source/Scene/PostProcessStageTextureCache.js
@@ -111,6 +111,9 @@ define([
         } else {
             for (j = 1; j < length; ++j) {
                 name = getLastStageName(composite.get(j));
+                if (!defined(dependencies[name])) {
+                    dependencies[name] = {};
+                }
                 dependencies[name][originalDependency] = true;
             }
         }