Re: Creating a radar sweep effect
Re: Creating a radar sweep effect
- Subject: Re: Creating a radar sweep effect
- From: Uli Kusterer <email@hidden>
- Date: Mon, 28 Sep 2009 14:46:36 +0200
Am 27.09.2009 um 08:50 schrieb Graham Cox:
I have used this approach to simulate an oscilloscope display and it
works well in terms of realism, but performance can be an issue.
You'll probably need to store at least 3 or 4 "previous" frames to
get the effect you want - there's no really good way to do it in one
pass and get realism.
One way to improve performance would be to use CALayers or CGLayers.
Have a pool of five previous layers, and reuse the oldest of those for
the new image. By using layers, you can let the graphics card do the
merging of the six frames, and the expensive drawing only happens
once. Play with the layer alpha to have them fade out.
Haven't tried this, but it's something I'd attempt if I was pressed
for performance.
Cheers,
-- Uli Kusterer
"The Witnesses of TeachText are everywhere..."
http://groups.yahoo.com/group/mac-gui-dev/
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