On 7/6/2010 3:16 PM, Robert Osfield wrote:
> Hi Cory,
>
> This is expected behaviour as the draw callback is nested within
the
> code that sets up display lists, so once the display list is
created
> it'll not call the callback again. If you disable the use of
display
> lists via drawable->setUseDisplayLists(false); then your
callback will
> be called on every frame.
>
> Another approach you could take to switching on/off various
subgraphs
> is to use a combination of NodeMask and CullMask. Have a look at
the
> osgstereoimage example for inspiration on this approach.
>
> Robert.
>
> On Tue, Jul 6, 2010 at 8:19 PM, Cory Riddell <
c...@codeware.com>
wrote:
>
>> I have a very simple draw callback defined that uses a bool to
decide if
>> the drawable should be drawn. The body of the callback's
>> drawImplementation() looks like:
>>
>> if (m_enable)
>> {
>> drawable->drawImplementation(renderInfo);
>> }
>>
>> I have drawables scattered all over my scene that use the same
instance
>> of this callback. By doing this, I'm able to toggle all of
those
>> drawables on or off by setting a single bool.
>>
>> This only seems to work though if the drawable has display
lists
>> disabled. My code to set the callback looks like:
>>
>> drawable->setUseDisplayList(false);
>> // callback is my shared callback instance
>> drawable->setDrawCallback(callback);
>>
>> Is this expected behaviour? If I understand this correctly, to
use
>> display lists, I would have to tell each drawable to recompile
>> (dirtyDisplayList()) whenever I toggle my m_enable bool. Since
the whole
>> point of my shared draw callback is to avoid traversing my
graph, doing
>> so would defeat the purpose of my callback. So, do I
understand this
>> correctly?
>>
>> It looks like display lists can prevent a draw callback from
being
>> called. Is that right?
>>
>> Cory
>>
>>
>>
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>>
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>>
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>>
>>
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