Re: Alpha-channeled images fade to black?
Re: Alpha-channeled images fade to black?
- Subject: Re: Alpha-channeled images fade to black?
- From: Allan Odgaard <email@hidden>
- Date: Thu, 18 Mar 2004 22:34:38 +0100
On 18. Mar 2004, at 21:02, Jonathan del Strother wrote:
I'm loading .tiff files through NSImage into an OpenGL texture. Where
the texture is semi-transparent, it's much darker than the opaque
areas, as if the image color is getting multiplied by the color of the
alpha channel, in addition to the alpha channel providing the
transparency.
This is only a hunch, but I do recall reading that
Cocoa/Quartz/whatever stores the images in a pre-multiplied alpha
state. Most likely OpenGL do not expect this (and that would give you
the double-alpha effect, dimming the source image too much).
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