obviousAlexC/penPlus: Fix texture handling between versions of pen+ (#…

…1510)

this fixes one half of #1508 the other half is from the blocks making the depth being negative.
Thanks to https://github.com/penta-quark-neutro for reporting this bug.
I have migrated the costume handling from the experimental version

extensions/obviousAlexC/penPlus.js

@@ -3133,8 +3133,10 @@
             curTarget.setCostume(costIndex);
           }
 
-          currentTexture =
-            renderer._allSkins[curCostume.skinId]._uniforms.u_skin;
+          currentTexture = renderer._allSkins[curCostume.skinId]._texture;
+
+          if (!currentTexture)
+            currentTexture = renderer._allSkins[curCostume.skinId].getTexture();
         }
       }