If I was going to turn this code into an image unit
would float y expect values in the range 0 to 1?
--- Ralph Brunner <email@hidden> wrote:
> Hi,
>
> note that the kernel code below has a bug, in that
> the sampler
> transform is applied twice. This will fail in
> interesting ways if the
> sampler transform is not identity (when Core Image
> tiles the
> evaluation for example).
>
> A different implementation could look like this:
>
> kernel vec4 linearImage(sampler image, float y)
> {
> vec2 xy = vec2(destCoord().x, y);
>
> return sample(image, samplerTransform(image,
> xy));
> }
>
> - Ralph
>
>
> --- Sam Kass <email@hidden> wrote:
> > Core Image kernel functions are called once for
> each
> > output pixel.
> > If I understand LinearImage, it's picking one
> raster
> > (y value) out of
> > the image and displaying that for the whole image?
> > If so, then for
> > each output pixel, you want to return the pixel
> that
> > is in the same
> > column, but a specified row. To duplicate what's
> on
> > the web site,
> > try something like the following, and hook it up
> to
> > a mouse input
> > (I'm coding in my email client, so there may be
> > bugs):
> >
> > kernel vec4 linearImage(sampler image, float
> ycoord)
> > {
> > // get xy value
> > vec2 xy = samplerCoord(image);
> > // return image pixels for our column,
> > specified row
> > return sample(image, samplerTransform(image,
> > vec2(xy.x, ycoord)));
> > }
> >
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