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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