{"action":"created","issue":{"url":"https://api.github.com/repos/phetsims/vibe/issues/3","labels_url":"https://api.github.com/repos/phetsims/vibe/issues/3/labels{/name}","comments_url":"https://api.github.com/repos/phetsims/vibe/issues/3/comments","events_url":"https://api.github.com/repos/phetsims/vibe/issues/3/events","html_url":"https://github.com/phetsims/vibe/issues/3","id":20311193,"number":3,"title":"Performance degradation on iPad dragging","user":{"login":"samreid","id":679486,"avatar_url":"https://avatars.githubusercontent.com/u/679486?v=3","gravatar_id":"","url":"https://api.github.com/users/samreid","html_url":"https://github.com/samreid","followers_url":"https://api.github.com/users/samreid/followers","following_url":"https://api.github.com/users/samreid/following{/other_user}","gists_url":"https://api.github.com/users/samreid/gists{/gist_id}","starred_url":"https://api.github.com/users/samreid/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/samreid/subscriptions","organizations_url":"https://api.github.com/users/samreid/orgs","repos_url":"https://api.github.com/users/samreid/repos","events_url":"https://api.github.com/users/samreid/events{/privacy}","received_events_url":"https://api.github.com/users/samreid/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/phetsims/vibe/labels/bug","name":"bug","color":"fc2929"},{"url":"https://api.github.com/repos/phetsims/vibe/labels/Summer%202015%20redeploy","name":"Summer 2015 redeploy","color":"5319e7"}],"state":"open","locked":false,"assignee":{"login":"jbphet","id":3082831,"avatar_url":"https://avatars.githubusercontent.com/u/3082831?v=3","gravatar_id":"","url":"https://api.github.com/users/jbphet","html_url":"https://github.com/jbphet","followers_url":"https://api.github.com/users/jbphet/followers","following_url":"https://api.github.com/users/jbphet/following{/other_user}","gists_url":"https://api.github.com/users/jbphet/gists{/gist_id}","starred_url":"https://api.github.com/users/jbphet/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jbphet/subscriptions","organizations_url":"https://api.github.com/users/jbphet/orgs","repos_url":"https://api.github.com/users/jbphet/repos","events_url":"https://api.github.com/users/jbphet/events{/privacy}","received_events_url":"https://api.github.com/users/jbphet/received_events","type":"User","site_admin":false},"milestone":null,"comments":5,"created_at":"2013-10-01T05:40:41Z","updated_at":"2015-06-23T22:06:38Z","closed_at":null,"body":"John Travoltage performance in dragging the leg is smooth in:\r\nhttp://www.colorado.edu/physics/phet/dev/html/john-travoltage/0.0.0-dev.10/john-travoltage_en.html\r\n\r\nand slow (like 2 frames per second) in:\r\nhttp://www.colorado.edu/physics/phet/dev/html/john-travoltage/0.0.0-dev.11/john-travoltage_en.html\r\n\r\nI tracked the problem to vibe's workaround for iOS/Safari.  Here is my conclusion from the Travoltage ticket https://github.com/phetsims/john-travoltage/issues/30:\r\n\r\nThis is very confusing, but if I use vibe/master (aka https://github.com/phetsims/vibe/commit/91a7145c36eafb4a28f32d9335a393c98f729e66) performance is chunky on dragging the leg or arm in Travoltage.  But if I add these two lines:\r\n\r\n```javascript\r\n  if ( platform.mobileSafari ) {\r\n    +var silenceDomNode = document.createElement( 'audio' );\r\n    +document.body.appendChild( silenceDomNode );\r\n```\r\n\r\nat the bottom, then performance becomes smooth again.  I am not sure why."},"comment":{"url":"https://api.github.com/repos/phetsims/vibe/issues/comments/114655514","html_url":"https://github.com/phetsims/vibe/issues/3#issuecomment-114655514","issue_url":"https://api.github.com/repos/phetsims/vibe/issues/3","id":114655514,"user":{"login":"jbphet","id":3082831,"avatar_url":"https://avatars.githubusercontent.com/u/3082831?v=3","gravatar_id":"","url":"https://api.github.com/users/jbphet","html_url":"https://github.com/jbphet","followers_url":"https://api.github.com/users/jbphet/followers","following_url":"https://api.github.com/users/jbphet/following{/other_user}","gists_url":"https://api.github.com/users/jbphet/gists{/gist_id}","starred_url":"https://api.github.com/users/jbphet/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jbphet/subscriptions","organizations_url":"https://api.github.com/users/jbphet/orgs","repos_url":"https://api.github.com/users/jbphet/repos","events_url":"https://api.github.com/users/jbphet/events{/privacy}","received_events_url":"https://api.github.com/users/jbphet/received_events","type":"User","site_admin":false},"created_at":"2015-06-23T22:06:38Z","updated_at":"2015-06-23T22:06:38Z","body":"@samreid: The workaround is the one that you referred to in the initial creation of the issue when you said:\r\n\r\n> I tracked the problem to vibe's workaround for iOS/Safari.\r\n\r\nIts purpose is to make sound work on an iPad by playing silence the first time the user touches anything in the sim.  There is more info in the code comments.  It is currently on lines 182-196 Sound.js in the vibe repository."}}