René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Redraws Cannot Be Synchronized","articleBody":"Originally reported in the Tracker on the SourceForge project, 2000-Dec.-27, http://bit.ly/SZfe3U\n\n**Without synchronizing redraws, the user will see partially updated scenes, likely in an incoherent state.**\nThis makes vpython unusable for animated scenes with nontrivial computation per frame, which includes everything I intended to use it for.\n\nI would like to be able to do something like this:\n\n``` python\nscene.autoredraw = false # disable unsynchronized redraws\nwhile myUpdate( scene ):\n    scene.redraw( minInterval ) # synchronized redraw between updates\n```\n\nThe original reporter suggested this:\n\n``` python\nwhile 1:\n    visual.stop() # suspend the visualization thread\n    doMyCalculations()\n    visual.start() # resume the visualization thread\n    visual.rate(30)\n```\n\n**For one easy to see example of the problem:**\nRun my code at http://pastebin.com/srsZLKWR and make it continuously advance (by clicking on a blue arrow, dragging the mouse, and then holding the button down).\nOn my computer you can see the particles update before the field arrows, and you can watch the updating of the field arrows propagate through the field.\nI can't tell how much time is spent updating the scene and how much time is spent drawing intermediate states that are not intended to be seen, but I expect eliminating the unnecessary redraws would improve performance as well as prevent drawing incoherent states.\n","author":{"url":"https://github.com/ShadSterling","@type":"Person","name":"ShadSterling"},"datePublished":"2012-07-28T22:33:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/4/visual/issues/4"}