[osg-users] Minor change proposal : Blacklist usage of all unsized texture internat format

Robert Osfield robert.osfield at gmail.com
Mon Aug 13 23:14:02 PDT 2018

Hi Jilien,

My priority for the OpenSceneGraph is stability and backwards compatibility.

So if you are suggesting that is something the breaks backwards
compatibility/change behaviour then it's a problem.

OpenSceneGraph and OpenGL have evolved together over nearly two
decades, both are now in mature phase of their life.  New features of
OpenGL/OpenSceneGraph can't break the old features that existing users
are using.  Breaking old features just creates pain for users and more
support work.

So for this task rather than black listing the priority has to how to
wokr out how to keep existing applications working without changes.


On Tue, 14 Aug 2018 at 02:30, Julien Valentin
<julienvalentin51 at gmail.com> wrote:
> Hi,
>  the support for unsized internal format is quite oldish...
> it's quite a miracle that calls to glTexImage2D still work with both internalformat (rawdatadescription) and format (memory layout) set to GL_RGBA
> -How can GLknow what we want in that case? there's definitly a default sized internalformat for GL_RGBA ...-
> In my sense
> -unsized internal formats should not have been supported by osg at the first place.
> -the argument 'format' in osg usage of glTexImage ( _sourceFormat ? _sourceFormat : _internalFormat) is completely wrong
> (you can't substitute a format with a sizedinternalFormat, that's 2 different stuff)
> In the case with image attached
>  we can deduce a proper _internalformat from Image::_pixelFormat (customisation of this behavior is the reason of being of _internalFormatMode),
> In the case no image is setted  (_internalFormatMode==USE_USER_DEFINED_FORMAT)
> we only can deduce format (_sourceFormat) and type(_internalFormatType) from a sized internalformat.
> internalformat concernq GPUside representation and is mandatory to be specified by user.
> My proposal would be
> -to black list unsized format in order user code work both with the presence or not of glTexStorage
> -to force user to set its own sourceFormat when no image attached
> Is it so controversal?
> Cheers,
> Julien[/list]
> ------------------------
> Twirling twirling twirling toward freedom
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=74505#74505
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