Thanks Ivan! That does work. Pixel perfect.
Ivan Busquets wrote:
I'm not sure that Posterize would give the desired result in this
case, since it will still throw values that are not possible to
represent as a half precision float.
You'd probably want to re-create a 16 bit half-float value by breaking
the 32 bit float into its exponent and mantissa(significant) values,
and then truncating those.
The following expression might work (not thoroughly tested, though)
set cut_paste_input [stack 0]
version 7.0 v4
push $cut_paste_input
add_layer {alpha alpha.red alpha.beta}
Expression {
expr0 "exponent(r) > 16 ? r*inf: ldexp(rint(mantissa(r)*
(2**11))/(2**11), exponent(r))"
expr1 "exponent(g) > 16 ? g*inf: ldexp(rint(mantissa(g)*
(2**11))/(2**11), exponent(g))"
expr2 "exponent(b) > 16 ? b*inf: ldexp(rint(mantissa(b)*
(2**11))/(2**11), exponent(b))"
channel3 alpha
name Float_To_Half
selected true
xpos 292
ypos 226
}
Hope that helps.
PS. Mark, hope you're doing well! :)
On Sun, Feb 17, 2013 at 5:35 AM, Shailendra Pandey <[email protected]
<mailto:[email protected]>> wrote:
well actually 281474976710656 -1
281474976710655
Hope that helps
On Sun, Feb 17, 2013 at 9:25 PM, Shailendra Pandey
<[email protected] <mailto:[email protected]>> wrote:
Hi Mark
You can use a posterize node
with a value of 281474976710656
which is 2 to the power(16*3)
Cheers
Shail
On Sun, Feb 17, 2013 at 6:25 AM, Mark Nettleton
<[email protected] <mailto:[email protected]>> wrote:
I'm generating an ST map within Nuke, that needs to line
up with 16 bit half float ST map images on disk.
Is there a way I can generate 16bit half float values
within nuke? Or convert 32 bit values to 16 bit half?
(without writing to disk and reading back)
Thanks
_______________________________________________
Nuke-users mailing list
[email protected]
<mailto:[email protected]>,
http://forums.thefoundry.co.uk/
http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
_______________________________________________
Nuke-users mailing list
[email protected]
<mailto:[email protected]>,
http://forums.thefoundry.co.uk/
http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
------------------------------------------------------------------------
_______________________________________________
Nuke-users mailing list
[email protected], http://forums.thefoundry.co.uk/
http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
_______________________________________________
Nuke-users mailing list
[email protected], http://forums.thefoundry.co.uk/
http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
