On Thu, Jul 15, 2010 at 11:19 AM, Robert Osfield <[email protected]>wrote:
> Hi Tim, > > I haven't yet looked at the submission so can't comment too much on > the approach. I was a bit surprised that that it was a StateAttribute > approach, as I was expecting something more closely aligned to the > current osg::Uniform support. > > Yeah, me too, but the the buffer bindings are global state and not something that needs to be set per program. > However, I'm not too familiar with the uniform blocks so I wouldn't > worry about my own expectations too much - I will have to dive into > the OpenGL feature, your submission and gets some hardware+drivers > that support uniforms blocks to learn about them myself. Now that > NVidia have released a well balanced Fermi card I'll be upgrading to > get myself some fully capable hardware, then I'll just have to work on > the other distractions... > > FYI, I'm doing the work on a 8600M. They are a core part of OpenGL 3.3, which is (well?) supported on that generation of cards. > At my end I'm juggling a couple of different tasks, some client work > improving 3D text support, shader composition and family commitments - > it's school holidays now so lots days out of the office. > Unfortunately this does mean that I don't have many slots available to > dive into other topics. So if you feel comfortable with the approach > your taking go for it, I'll try to get back and review the changes as > soon as I can. > > Thanks for you patience, > Robert. > > No prob. Tim > On Thu, Jul 15, 2010 at 9:30 AM, Tim Moore <[email protected]> wrote: > > Hi Robert, > > I'm wondering if you've had any chance to take a look at this submission. > I > > know that you're heads-down in shader composition and probably don't want > to > > want to think about any large submission, especially one that touches > state > > management. However, this doesn't touch State, StateAttribute etc. in any > > fundamental way. I ask because I'm thinking of going forward in two > > directions with this: filling in the missing features, and using the same > > approach to support transform feedback buffers. Do you have any comments > on > > the basic approach? > > Thanks, > > Tim > > > > On Wed, Jun 30, 2010 at 9:07 AM, Tim Moore <[email protected]> wrote: > >> > >> Hi, > >> Here is initial support for uniform buffer objects. The binding between > a > >> buffer object and an indexed target is implemented as a new > StateAttribute, > >> UniformBufferBinding. I've included an example program based on the code > in > >> the ARB_uniform_buffer_object specification. > >> A few things remain to do: > >> * The binding between a uniform block in a shader program and a buffer > >> indexed target number is fixed, like a vertex attribute binding. This is > too > >> restrictive because that binding can be changed without relinking the > >> program. This mapping should be done by name in the same way that > uniform > >> values are handled i.e., like a pseudo state attribute; > >> * There's no direct way yet to query for the offset of uniforms in > uniform > >> block, so only the std140 layout is really usable. A helper class that > >> implemented the std140 rules would be quite helpful for setting up > uniform > >> blocks without having to link a program first; > >> * There's no direct support for querying parameters such as the maximum > >> block length, minimum offset alignment, etc. Having that information > >> available outside of the draw thread would make certain instancing > >> techniques easier to implement. > >> Tim > > > > > > _______________________________________________ > > osg-submissions mailing list > > [email protected] > > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org > > > > > _______________________________________________ > osg-submissions mailing list > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org >
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