Good Stuff!
thanks for that Ivan :D
On Mon, Feb 18, 2013 at 1:04 PM, Michael Garrett <[email protected]>wrote:
> add_layer {alpha alpha.red alpha.beta}
>
> nice
>
>
> On 17 February 2013 13:55, Ivan Busquets <[email protected]> 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]>wrote:
>>
>>> well actually 281474976710656 -1
>>> 281474976710655
>>> Hope that helps
>>>
>>>
>>>
>>> On Sun, Feb 17, 2013 at 9:25 PM, Shailendra Pandey
>>> <[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]>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
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>
>>>>
>>>
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>>
>>
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>
>
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