The way I do this was to use a simple mask channel mask. Make a
CIFilter that lets you multiply the incoming frame by a vec4, and set
its components to 0 or 1 values, so if you only wanted the red
channel, you would multiply your image by vec4(1.0, 0.0, 0.0, 1.0)
(the last value is for alpha, depending on how you want to handle it,
you may want to premultiply or whatnot).
You then do this 3 times for each channel, and then, simply use
another simple CIKernel to add each component together from your 3
source images by doing something like
vec4 result = vec4(red.r, green.g, blue.b, red.a) (this keeps the red
alpha channel, but you can deal with it however you want).
Id be curious if there is a better way, but that works.
Attachment:
Color Mask.qtz Description: application/quartzcomposer
On May 8, 2008, at 2:38 PM, neb wrote:
A simple problem, I know the answer is right in front of me but
can't seem to find it...
How would I go about splitting a single image feed into RGBA or HSBA
component channels, so that I can process each channel individually
as images, and then reassemble (or not) later on in the chain? I'm
using QC3 on leopard.
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