[Sidefx-houdini-list] changed inputs

Chris Mangnall cm at dneg.com
Tue Jun 5 12:50:46 EDT 2007

Hi Edward - thanks very much for your help, it's all working as expected 
now.  I changed:

setDuplicateCount(input_num, getInput(input_num));


setDuplicateCount(input_num, ++myInputCookCount1);

..is that correct?  It seems to work...

Also, in the SOP I'm working on, I was allocating memory for 
input{1,2}_geo in the constructor, but i missed it out of this stripped 
down version.  It's a bit spooky that it doesn't crash for me...


Edward Lam wrote:
> Hi Chris,
> I got a crash as soon as I tried cooking your example because we were 
> passing uninitialized GU_Detail pointers. To get it to run at all, I 
> had to change input11_geo and input2_geo into full GU_Detail objects 
> and pass their addresses to duplicateChangedSource() like so:
> duplicateChangedSource(1, context, input1_top, &changed1, &input1_geo);
> duplicateChangedSource(2, context, input2_top, &changed2, &input2_geo);
> After that, it worked as expected because that version of 
> duplicateChangedSource() which takes a GU_Topology only notifies of 
> topology changes and not point position changes.
> If you used the other versions of duplicateChangedSource() without 
> GU_Topology, then it will notify of any changes in the input. However, 
> it will necessarily duplicate the particular input's geometry into 
> your current gdp, which you may or may not want.
> So for the other inputs, you may wish to consider using 
> SOP_Node::checkChangedSourceFlags() for changes, and then manually 
> updating the duplicate counter yourself instead of relying on 
> duplicateChangedSource(). Something like this (UNTESTED):
> - Create a member variable to keep track of the cook counter.
>   eg. int myInputCookCount1;
> - In your cookMySop() method:
>   int input_num = 1;
>   checkChangedSourceFlags(input_num, context, &changed1);
>   if (changed1)
>   {
>      SOP_Node *input = CAST_SOPNODE(getInput(input_num));
>      if (input && input->error() < UT_ERROR_ABORT)
>      {
>          setDuplicateCount(input_num, getInput(input_num));
>          mySopFlags.setResetGeo(false);
>       }
>   }
> Cheers,
> -Edward
> Chris Mangnall wrote:
>> Hi Edward,
>>  Attached is a simple SOP and hip file.  Changing the topology of the 
>> grids triggers a change, but simply translating them around doesn't...
>> I'm using houdini 8.2.66 and uname -a
>> Linux henley 2.6.17-1.2143_FC4smp #1 SMP Mon Jul 31 17:51:15 BST 2006 
>> x86_64 x86_64 x86_64 GNU/Linux
>> Edward Lam wrote:
>>> Hi Chris,
>>> It should work. Try stripping your problem down to as simple a SOP 
>>> as possible first. And if that doesn't work, try posting your simple 
>>> code to the list. Make sure you're giving it the correct input 
>>> index. :)
>>> I assume you're using Houdini 7.0 or later though. In earlier 
>>> versions, it would only work for a single input.
>>> -Edward
>>> Chris Mangnall wrote:
>>>> Hi - HDK question...
>>>> Is there a reliable way to determine if a SOP input has changed at 
>>>> all?  I'm using duplicateChangedSource(...) and fetching the 
>>>> 'changed' flag, but the flag returns 0 if i just transform/edit the 
>>>> input points.
>>>> I'm writing a three-input deformer SOP, and there's a whole bunch 
>>>> of heavy processing that only needs to be done if either of the 
>>>> first two inputs have changed.
>>>> c
>>>> _______________________________________________
>>>> Sidefx-houdini-list mailing list
>>>> Sidefx-houdini-list at sidefx.com
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