[osg-users] design issues

[Robert Osfield]

I don't have time to dive deeply in user projects, I can do quick
scans of email and provide quick replies where possible.  In terms of
optimization I'd say avoiding the inverse matrix might be useful.
Using the Matrix.postMultTrans/preMultTrans would also be another
optimization step you could use.  The use of the UserValue looks like
it won't be thread safe or even safe n the presence of multiple cull
traversals.

On 3 November 2016 at 11:40, Trajce Nikolov NICK
<trajce.nikolov.nick at gmail.com> wrote:
> Thanks Robert,
>
> I am aware of it, it is already used in my second snippet. Here it is: (is
> it done properly?)
>
> void MyCullVisitor::apply(osg::LightSource& node)
> {
>
>     osg::Matrixd inverseViewMatrix =
> osg::Matrixd::inverse(getCurrentCamera()->getViewMatrix());
>     osg::Matrixd worldMatrix = inverseViewMatrix * (*getModelViewMatrix());
>
>     osg::Vec3d pos(node.getLight()->getPosition().x(),
> node.getLight()->getPosition().y(), node.getLight()->getPosition().z());
>     worldMatrix = osg::Matrixd::translate(pos) * worldMatrix;
>
>     node.setUserValue("WorldMatrix", worldMatrix);
>     if (node.getLight()->getLightNum() == 0)
>     {
>         osgUtil::CullVisitor::apply(node);
>     }
> }
>
>
> On Thu, Nov 3, 2016 at 9:14 AM, Robert Osfield <robert.osfield at gmail.com>
> wrote:
>>
>> Hi Nick,
>>
>> The osgUtil::CullVisitor has the maintains a stack of ModelViewMatrix
>> that it accumulates through the the scene graph traversal, you should
>> just need to get the top of this stack using
>> cullVisitor->getModelViewMatrix().
>>
>> Robert.
>>
>> On 2 November 2016 at 22:25, Trajce Nikolov NICK
>> <trajce.nikolov.nick at gmail.com> wrote:
>> > Hi Community,
>> >
>> > I am trying to optimize the rendering. Getting huge update numbers.
>> >
>> > The story is this:
>> > My scene has huge number of lights, some are static (streetlights) some
>> > dynamic (a car). The lighting engine needs the World matrix of a
>> > LightSource
>> > and the ViewMatrix (which is the same as the World inverse just with
>> > some
>> > extra rotation). In my code after the update before the rendering
>> > traversal
>> > I am updating these matrices each frame and I am about to place this
>> > code in
>> > my custom CullVisitor (which traverse the scene anyway but only the
>> > active
>> > children).
>> >
>> > Here is my approach at the moment: list of light entities and here is
>> > how I
>> > am computing these:
>> > http://pastebin.com/0A64sc7Y
>> > Simply getting the NodePath and computing the world matrix from this
>> > node
>> > path. This seams to be costly
>> >
>> > I am after wiser optimization, to place this in my CullVistor: Here is
>> > the
>> > snippet:
>> > http://pastebin.com/6dQnih8N
>> >
>> > These snippets are simple and I would like to ask if this is more proper
>> > way, which it seams to me since I will gain more performance by updating
>> > only the culled and active nodes. Also the math in the cull visitor.
>> >
>> > Thanks a lot for any hints, ideas. As always :-)
>> >
>> > Cheers,
>> > Nick
>> >
>> > --
>> > trajce nikolov nick
>> >
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>> >
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>> >
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>
>
>
>
> --
> trajce nikolov nick
>
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