Re: Images with direct memory access
Re: Images with direct memory access
- Subject: Re: Images with direct memory access
- From: Eric Wing <email@hidden>
- Date: Fri, 27 Jul 2012 16:51:13 -0700
On 7/27/12, Jens Alfke <email@hidden> wrote:
> Keep in mind that accessing the image pixels directly can hurt drawing
> performance. Your code can only access the pixmap if it's in system RAM,
> while GPU acceleration requires that the pixmap be in VRAM. So messing with
> the pixels may either cause the pixmap to be copied back and forth, or force
> CoreGraphics to degrade to software rendering.
>
> —Jens
Jens is correct that the way you are implying you want to access
pixels will hurt performance. So this is what shaders are for. If want
fast access that will immediately be rendered, use OpenGL shaders or
Core Image (an Apple framework).
-Eric
--
Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden