Re: [osg-users] multiple views + instancing

[Robert Osfield]

Hi David,

You could write a custom subclass of osg::Geometry and override the
drawImplementation an do the cull and dispatch of the primitives and
instance count for each time the geometry is drawn, but do so in a
thread safe way such as my computing all the dynamic data on the fly.

The alternative would be to have two osg::Geometry, once for each view
and have a NodeMask for each osg::Geometry and have use a
Camera::CullTraversalMask for each view to select the appropriate one
for each context.


Robert.

On 15 November 2017 at 19:06, David Heitbrink  wrote:
> Right now I having problems setting unique uniforms and num instances on a 
> per view basis (camera).
>
> Right now I am using hardware instancing, with a scene with 1000's of 
> relatively complex objects, but only a handful of actual models. I was able 
> to encode index's to textures + position and rotation transforms into a 
> single texture buffer.
>
> To do the viewport culling for this I added "proxy" nodes, which are just 
> osg::group nodes, with a compute bound + cull call backs. The cull call back, 
> calls back to a class tracking which instances are visible in which view. 
> Each view has a group attach to it between the camera and the main scene. In 
> said group, the texture buffer object is attached here.
>
> The instanced models are further down in the scene graph. I in a draw 
> callback from camera, I update each models uniform for its offset into the 
> texture buffer, its instance count, plus texture buffer (transforms + some 
> options for the fragment shader).  All of this works great until I have 
> multiple cameras.
>
>  Basically I cannot figure out a good way of modifying the instance count + 
> offset uniform so I get unique values for each camera. Does anyone have some 
> advice for this?
>
> --
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=72391#72391
>
>
>
>
>
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Re: [osg-users] multiple views + instancing

[David Heitbrink]

I am using osg 3.4.0. I am in a position where I could switch to a newer build.

--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=72392#72392





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[osg-users] multiple views + instancing

[David Heitbrink]

Right now I having problems setting unique uniforms and num instances on a per 
view basis (camera). 

Right now I am using hardware instancing, with a scene with 1000's of 
relatively complex objects, but only a handful of actual models. I was able to 
encode index's to textures + position and rotation transforms into a single 
texture buffer.

To do the viewport culling for this I added "proxy" nodes, which are just 
osg::group nodes, with a compute bound + cull call backs. The cull call back, 
calls back to a class tracking which instances are visible in which view. Each 
view has a group attach to it between the camera and the main scene. In said 
group, the texture buffer object is attached here.

The instanced models are further down in the scene graph. I in a draw callback 
from camera, I update each models uniform for its offset into the texture 
buffer, its instance count, plus texture buffer (transforms + some options for 
the fragment shader).  All of this works great until I have multiple cameras.

 Basically I cannot figure out a good way of modifying the instance count + 
offset uniform so I get unique values for each camera. Does anyone have some 
advice for this?

--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=72391#72391





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