Hello Johannes,

Johannes Brunen wrote:
>> Carsten Neumann wrote:
>>> Johannes Brunen wrote:
>> In 2 there is a ChunkOverrideGroup which allows overriding a specific 
>> chunk of a material.
> That is good news. I'm excited...
> 
> 
>>> 4. I have had problems with the "--jobs=4" switch of the scons
> system.
>>> Is this a known problem? Is it supported by OpenSG at all?
>> ..., but for 2 I use -j4 all the time and it works fine.
>> What problems did you have ?
> 
> I have had build errors on incremental builds which did vanish when I
> tried without the -j4 option. 
> 
> I just verified it as follows:
> First I changed a cpp file from the system lib. Then I run the following
> command from my shell
> 
> ./scons --jobs=4 compiler=msvc71 type=dbg contrib_ply=yes
> 
> which leads to the following error:
> 
> LINK : fatal error LNK1104: cannot open file
> 'Build\win32-msvc71\installed\lib\OSGSystemD.lib'
> scons: *** [Build\win32-msvc71\Source\Contrib\OSGContribD.dll] Error
> 1104
> scons: building terminated because of errors.
> 
> Trying again the same procedure but with the command
> 
> ./scons compiler=msvc71 type=dbg contrib_ply=yes
> 
> does not show an error at all.

hm, looks like there is a dependency missing.

>>> 5. Should I switch to OpenSG 2.0 framework or should I wait further?
> ...
>> ...
>> The generic answer is something like this: If you don't need any of
> the 
>> features that 2 lacks compared to 1, ...
> 
> Oh, that is a difficult one for me. Can I read up what is still missing
> from OpenSG 2.0 against 1.8. Is the content of 
> http://opensg.vrsource.org/trac/wiki/Dev/FeaturesToPortFrom1to2
> up to date?

No, unfortunately not. The biggest thing that comes to mind are the more 
advanced shadow map variations, 2 only has an implementation of the 
basic algorithm.

> Did anyone take the time to diff the branches?
> However, I do not want to bother. OpenSG 2.0 is not released. So I will
> be patient.
> 
>> One exception is perhaps if you 
>> have some cores that do complicated stuff for rendering, ...
> What are these?

Sorry, I was a bit terse here. I was referring to NodeCores (the things 
that define the semantics of a node, e.g. Transform). If you have 
written your own ones (like MultiSwitch) and these interact with the 
RenderAction in non-trivial ways (*not* like MultiSwitch) you might have 
to adapt for the shader compositing framework Gerrit is planning.

> Nevertheless, I will give the OpenSG 2.0 branch a try...

Yes, please do. I would suggest taking a look at the contents of 
Examples/Simple or Examples/Tutorial (together with the parts of the 
online tutorial that are "ported") to get you started.

>>> 7. Is it possible to build multiple build types (opt,dbg)
>>> simultaneously? I tried "type=dgb,opt" but that doesn't work.
>> probably not. Personally I'm not a big fan of this type of thing, 
>> because it makes the build system (even more) complicated and you can 
>> easily get the same thing by opening two consoles.
> 
> I didn't know that it is possible to run two scons processes
> concurrently on the same build system.

hm, now that you mention it, I'm not sure if it is officially supported, 
but I did not run into any problems so far.

[SNIP]

>>> 9. Would it be of interest to support custom memory management
> handlers?
>> Sounds interesting as well. How does it integrate and how do you
> control 
>> which mem management is used ? OpenSG basically uses new/delete, so to
> 
>> affect it those would have to be replaced (globally).
> Yes, that is exactly how it works. I simply link an object to the
> libraries ('NewDeleteImpl.obj' and 'NewDeleteImplD.obj', rsp) providing
> the globally defined functions:
> 
> void* ::operator new(size_t size) { ... }
> void* ::operator new[](size_t size) { ... }
> void ::operator delete(void *pObj) { ... }
> void ::operator delete[](void *pObj) { ... }
> 
> These itself are delegating into my custum memory manager. This works
> pretty fine and I use it all over my code.
> 
>> Does this mem management give you performance benefits ? 
> 
> I can't answer that for the OpenSG code. For my application I could
> actually measure a huge performance gain comparing to the standard
> visual C++ memory manager. I use the
> http://www.nedprod.com/programs/portable/nedmalloc/index.html as a base
> and I'm pretty fine with it. An alternative is the Hoard memory
> allocator http://www.cs.umass.edu/~emery/hoard/ which is a very fine
> piece of software. 
> However, the reason for changing the default memory allocator for the
> OpenSG (and other) library(ies) is not performance per se, but the
> effort of centralizing the memory management and the possibility to
> interfere the allocation proccess. For instance adding safe memory
> blocks around a requested memory block, and later on testing these bocks
> on some installed memory pattern can easily show memory corruption. Or
> counting the actually used memory is always of interest.

ok, thanks for the explanation.

>> In OpenSG 
>> object creation is a rather expensive operation because of the
> multiple 
>> aspect and registration stuff that happens.
> Hmm,...
> 
> 
>>> If there is any interest I could post this
>>> file to the list.
>> yes, please. Even if I don't get around to integrate it right away we 
>> have it in the archives and perhaps someone finds it interesting
> enough 
>> to make similar changes for linux/os x ;)
> So, here it goes...

thank you. I'm somewhat busy ATM with stuff that has deadlines attached 
to it, so it might take me a while before I can integrate it. So if 
someone beats me to it... ;)

        regards,
                Carsten

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