{"id":848,"date":"2018-10-05T18:03:03","date_gmt":"2018-10-05T18:03:03","guid":{"rendered":"https:\/\/lab.florianschwarz.net\/PennController\/?post_type=yada_wiki&p=848"},"modified":"2018-11-07T04:15:46","modified_gmt":"2018-11-07T04:15:46","slug":"preloading-resources","status":"publish","type":"yada_wiki","link":"https:\/\/lab.florianschwarz.net\/PennController\/wiki\/preloading-resources\/","title":{"rendered":"Preloading Resources"},"content":{"rendered":"

By default, all the resources start<\/em> to preload when the experiment page opens, and each PennController<\/code> trial checks that the specific resources it uses are preloaded before it starts.<\/p>\n

You can change this behavior and have control over when<\/strong> and which<\/strong> resources should be checked for preloading by using the command PennController.CheckPreloaded<\/a><\/code>.<\/p>\n

[js]PennController.CheckPreloaded()[\/js] creates an item that checks that all<\/strong> the resources are preloaded before proceeding. You can also specify that only the resources used by certain items should be checked: <\/p>\n

[js]
\nPennController.CheckPreloaded(
\n startsWith(“practice”)
\n ,
\n startsWith(“test”)
\n ,
\n “exitItem”
\n)
\n[\/js]<\/p>\n

This code will create an item that checks preloading for the resources of all the PennController trials whose label starts with practice<\/code> or test<\/code>, or is<\/em> exitItem<\/code>, and only those.<\/p>\n

Finally, you can pass a number as the last argument to specify a delay (in milliseconds) after which, even if not all the resources have been preloaded, the next item in the sequence should start anyway:<\/p>\n

[js]
\nPennController.CheckPreloaded(
\n startsWith(“test”)
\n ,
\n 5000
\n)[\/js]<\/p>\n

To control when<\/strong> in the flow of your experiment the resources should be checked for preloading, use the label<\/code> command onto the item generated by PennController.CheckPreload<\/code> to assign it a label, and refer to it in PennController.Sequence<\/a><\/code>.<\/p>\n

Complete Example<\/h2>\n

[js try=”data”]
\nPennController.ResetPrefix( null );<\/p>\n

PennController.Sequence( “welcome” , “preloadPractice” , startsWith(“practice”) , “preloadTest” , startsWith(“Test”) );<\/p>\n

PennController.AddHost( “http:\/\/files.lab.florianschwarz.net\/ibexfiles\/PennController\/SampleTrials\/” );<\/p>\n

PennController.CheckPreloaded( startsWith(“Practice”) )
\n .label( “preloadPractice” );<\/p>\n

PennController.CheckPreloaded( startsWith(“Test”) )
\n .label( “preloadTest” );<\/p>\n

PennController( “welcome” ,
\n newText( “message” , “Welcome. The resources are currently being preloaded. The next trial won’t start before all the resources for the ‘practice’ trial are loaded (i.e. 1fishSquareTank.png).”)
\n .print()
\n ,
\n newButton(“start”, “Start”)
\n .print()
\n .wait()
\n);<\/p>\n

PennController( “practice-1” ,
\n newImage(“tank”, “1fishSquareTank.png”)
\n .print()
\n ,
\n newText(“description”, “The tank is round.”)
\n .print()
\n ,
\n newKey(“validate”, “FJ”)
\n .wait()
\n);<\/p>\n

PennController( “practice-2” ,
\n newImage(“tank”, “1fishSquareTank.png”)
\n .print()
\n ,
\n newText(“description”, “The tank is square.”)
\n .print()
\n ,
\n newKey(“validate”, “FJ”)
\n .wait()
\n);<\/p>\n

PennController( “Test-1” ,
\n newImage(“tank”, “2fishRoundTank.png”)
\n .print()
\n ,
\n newText(“description”, “The tank is round.”)
\n .print()
\n ,
\n newKey(“validate”, “FJ”)
\n .wait()
\n);<\/p>\n

PennController( “Test-2” ,
\n newImage(“tank”, “2fishRoundTank.png”)
\n .print()
\n ,
\n newText(“description”, “The tank is square.”)
\n .print()
\n ,
\n newKey(“validate”, “FJ”)
\n .wait()
\n);
\n[\/js]<\/p><\/div>
\n

Index<\/h3>\n