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Hi,
I use a png file for an atlasspritemanager. The atlasspritemanager uses the wrong blending mode as it thinks the texture does NOT have premultiplied alpha.
When the texture is loaded:
_hasPremultipliedAlpha = (info == kCGImageAlphaPremultipliedLast || info == kCGImageAlphaPremultipliedFirst);
is FALSE.
Doesnt have png file always premult. alphas? I am creating the png files with a script, is it possible to do something wrong here?
Thomas
This same error was reported 2 or 3 days ago. please search the forum.
it's already fixed on the svn.
the .png images can have or not the alpha premultiplied.
By default, on the device, XCode compresses the .png images (creating alpha premultiplied png images).
On the simulator the XCode doesn't compress the .png images.
yes, as I said in the previous post a PNG can have alpha premultiplied or not.
XCode only compresses the PNG (alpha premultiplied) when the target is the device.
It doesn't compress them when the target is the Simulator, even if you have told XCode to do so.
Kind of a dumb question, but based on this thread and what I'm seeing, it appears that the Simulator will act differently from the Device when it comes to compressing images, and thus, blending of images.
What's the best way to handle this such that the Simulator and Device act in the same manner? Are there preprocessor directives that can look at which Active SDK you're using? Or am I just missing something here?
I don't know too much about premultiplied alpha images so I'm a bit lost in this arena.
Steve Oldmeadow
Administrator
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