Re: [osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0.

[Robert Osfield]

Hi Scott,

The problem under OSX looks to be a driver bug, there is small chance that
it's related to the problems you are seeing but likely a different issue.

The problem you describe sounds like a driver bug too, testing out without
other drivers/hardware/OS combinations would help with this.  Have you
tried any other combinations?

There is possibility that different drivers handle the input data in
different ways.  The addition of the glTextureStorage2D usage might be
adding another code pathway in the drivers that adds/removes/changes the
way that data is handled introducing the inconsistency that you are seeing.
The driver shouldn't be doing this, but no code is perfect.

Without an example model that can reproduce the problem there isn't much
others can do at this stage.  Potentially we could add a catch for
compressed textures + mipmap levels into osg::Texture*, but before any mods
to the core OSG I'd need to have a test example to work from that exhibits
a problem so that can confirm that these changes actually work.

Robert.

On 23 September 2015 at 22:24, Davis, Timothy S CTR comnavairsyscom <
timothy.s.davis@navy.mil> wrote:

> Robert
>
> Sorry for the bad posting of my last message.  I'll repeat here and update
> with new information.
>
> The code in question was added sometime during OSG 3.3.x development.  It
> was not in OSG 3.2.1.  I just recently jumped from 3.2.1 to 3.4.0 for my
> application which is when I ran into the problem.  It worked fine with OSG
> 3.2.1.  In particular, it appears to be the added support for texture
> storage objects and not specifically "compressed texture support".  I noted
> the call that gave the error was glCompressTexSubImage2D.  However I should
> point out that I determined this using gDEBugger.  My version doesn't seem
> to understand the texture storage extension.  So the error may have been
> generated by the earlier call to setup the texture storage.  I checked into
> this and indeed an INVALID_OPERATION was generated by the call to
> glTexStorage2D.
>
> In addition, on my machine the problem doesn't affect all compressed
> textures with mipmaps.  The model that first caused the problem had several
> such textures, but only a small 32x32 texture resulted in a problem.  I
> have no idea why this would be the case.  However I remember others
> reporting issues with loading DDS textures and working around it by
> commenting out the following line in ReaderWriterDDS:
> If ( mipmap_offset.size()>0) osgImage->setMipmapLevels(mipmap_offsets);
> Commenting that line out would appear to disable mipmaps for compressed
> textures and avoid the problems I've indicated.  This older problem was
> reported only on OSX, but may be related.  This type of changed made to the
> IVE loader would also have fixed my problem at the expense of disabling
> mipmaps.
>
> Looking at a different model, the one problem texture was 128x128.  So
> there appears to be nothing special about the size.  I did see that the
> rendering result for the models that have the problem is different between
> using the fixed-function pipeline and a shader.  With the FFP, the
> rendering appears correct, though the INVALID_OPERATION error is
> generated.  With a shader, the textures rendered black.
>
> I looked at making a simple model that would reproduce the problem.
> However, I've failed to create such a model.  It just always works with no
> render problems or OpenGL errors.
>
> For my application, I've worked around the problem by reducing the number
> of mipmap levels to avoid using levels smaller than the compression block
> size.  So I consider the problem fixed for me.  However, I feel this is
> information that you and the rest of the community can use.
>
>
> Scott
>
>
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Re: [osg-users] Modern GLSL and OSG

[Christian Buchner]

NOTE: the current development version of ANGLE is targeting OpenGL ES 3.0,
if you want to be more up to date. I am not sure about its level of
completion and stability though.

Maybe you can find more complete (commercial?) virtualization solutions to
run the DX backend. Also maybe Wine is suitable for this. DirectX 9.0c
should be well supported by Wine (or its commercial counterpart Crossover).

Christian


2015-09-23 14:49 GMT+02:00 Christian Buchner :

>
> If you're using Windows you could try building OSG against ANGLE
> and limit yourself to the OpenGL ES 2.0 API feature set. Here you can't
> accidentially fall back into using deprecated (fixed function) features
> because these have been stripped from the API.
>
> There would also be plenty of books about OpenGL ES 2.0 available - and
> you can immediately target mobile platforms (iOS, Android)
>
> Christian
>
>
> 2015-09-23 14:44 GMT+02:00 Garth D :
>
>>
>> Hi all,
>>
>> I was wondering if anyone can make some suggestions as to resources that
>> are useful for learning GLSL in modern OpenGL (say, 3.0+) with a specific
>> focus on use with OSG.
>>
>> My existing GLSL knowledge is weak compared to my general 3D knowledge,
>> and mostly dates back to the early days of shaders. A lot of what I have
>> personally done with OpenGL and OSG has involved the fixed-function
>> pipeline, or things that map to it fairly closely.
>>
>> Thus far I've been digging around online for GLSL resources, but tend to
>> frequently find myself doing it the wrong way as I'm using features that
>> have since become deprecated. On the OSG side I tend to dig around in the
>> OSG examples and search the source to try to find the OSG equivalents to
>> OpenGL calls I see mentioned in the GLSL resources. I then put these
>> together and if I'm lucky something useful comes out. :)
>>
>> I think I'll figure things out eventually if I continue to crash around
>> blindly as I have been, but if anyone can suggest some better starting
>> points for GLSL use in OSG specifically, it would be much appreciated. :)
>>
>> Cheers,
>> Garth
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>
>
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Re: [osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0

[Trajce Nikolov NICK]

Hi Scott,

I am experiencing this issue on OSX .. Can you submit a patch/fix to test
it against the problematic models I have?

Thanks a bunch!

Nick

On Thu, Sep 24, 2015 at 4:18 PM, Davis, Timothy S CTR comnavairsyscom <
timothy.s.davis@navy.mil> wrote:

> Robert
>
> I'd agree that I'm dealing with a driver bug.  I'm just not sure what the
> bug is.  I think we are working in a underspecified area of OpenGL when
> dealing with mipmap levels smaller than the compression block size.
> However, I know that my driver generates 2x2 and 1x1 mipmaps for hardware
> generated compressed textures and this would suggest that it should happily
> work with these levels.
>
> I don't agree that it is unrelated to the OSX driver issue.  Certainly the
> drivers are different and the symptoms may be different.  But they both
> appear to touch the same question; what happens with mipmaps smaller than
> the block size.  I don't have access to an OSX machine however, so I cannot
> investigate this claim further.
>
> I have not tried different driver/hardware/OS combinations.  I'd agree
> that this would be useful, but I'm somewhat limited in how far I can go
> with this.
>
> I'd agree that a change to the core OSG is not warranted at this time.
> The models that cause the problem are not distributable.  I may continue to
> try and create a model that has the issue as time permits.
>
> Scott
>
>
>
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-- 
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[osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0

[Davis, Timothy S CTR comnavairsyscom]

Robert

I'd agree that I'm dealing with a driver bug.  I'm just not sure what the bug 
is.  I think we are working in a underspecified area of OpenGL when dealing 
with mipmap levels smaller than the compression block size.  However, I know 
that my driver generates 2x2 and 1x1 mipmaps for hardware generated compressed 
textures and this would suggest that it should happily work with these levels.

I don't agree that it is unrelated to the OSX driver issue.  Certainly the 
drivers are different and the symptoms may be different.  But they both appear 
to touch the same question; what happens with mipmaps smaller than the block 
size.  I don't have access to an OSX machine however, so I cannot investigate 
this claim further.

I have not tried different driver/hardware/OS combinations.  I'd agree that 
this would be useful, but I'm somewhat limited in how far I can go with this.

I'd agree that a change to the core OSG is not warranted at this time.  The 
models that cause the problem are not distributable.  I may continue to try and 
create a model that has the issue as time permits. 

Scott




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[osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0

[Davis, Timothy S CTR comnavairsyscom]

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[osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0

[Davis, Timothy S CTR comnavairsyscom]

Sorry.  It keeps trying to encrypt the message.

Robert

While continuing to build a model that results in the problem, I discovered 
something I didn't see before.  The IVE model had an incorrect number of mipmap 
levels (it had 8) for a 32x32 texture.  It makes sense that glTexStorage2D 
would generate INVALID_OPERATION in this case.  Rebuilding the model from a 
source with uncompressed textures and recompressing the textures worked.  The 
original model was converted with a much older version of OSG, pre OSG 3 for 
sure.

So I was barking up the wrong tree:)

That addresses my specific issue without needing a change to OSG 3.4.0.  
However, I still think it is worth trying for the OSX case.


Trajce

In osg/Texture.cpp, function applyTexImage2D(), find the line:

useTexStorage &= sizedInternalFormat != 0;

add the following after the line:

if ( useTexStorage && compressed_image && numMipmapLevels > 2 )
{
numMipmapLevels -= 2;
}

This is clearly not production quality as it assumes block size is 4 and 
complete mipmaps to 1x1.  It should be enough to check the approach.  You may 
have to set GL_TEXTURE_MAX_LEVEL if the driver thinks the texture is 
incomplete, but I didn't have that issue.

Scott
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Re: [osg-users] INVALID_OPERATION with compressed textures with mipmaps in OSG 3.4.0

[Robert Osfield]

Hi Scott,

Thanks for the follow up.

Could you post the whole modified file, this way we can avoid any possible
copy and past errors.

Thanks,
Robert.

On 24 September 2015 at 20:13, Davis, Timothy S CTR comnavairsyscom <
timothy.s.davis@navy.mil> wrote:

> Sorry.  It keeps trying to encrypt the message.
>
> Robert
>
> While continuing to build a model that results in the problem, I
> discovered something I didn't see before.  The IVE model had an incorrect
> number of mipmap levels (it had 8) for a 32x32 texture.  It makes sense
> that glTexStorage2D would generate INVALID_OPERATION in this case.
> Rebuilding the model from a source with uncompressed textures and
> recompressing the textures worked.  The original model was converted with a
> much older version of OSG, pre OSG 3 for sure.
>
> So I was barking up the wrong tree:)
>
> That addresses my specific issue without needing a change to OSG 3.4.0.
> However, I still think it is worth trying for the OSX case.
>
>
> Trajce
>
> In osg/Texture.cpp, function applyTexImage2D(), find the line:
>
> useTexStorage &= sizedInternalFormat != 0;
>
> add the following after the line:
>
> if ( useTexStorage && compressed_image && numMipmapLevels > 2 )
> {
> numMipmapLevels -= 2;
> }
>
> This is clearly not production quality as it assumes block size is 4 and
> complete mipmaps to 1x1.  It should be enough to check the approach.  You
> may have to set GL_TEXTURE_MAX_LEVEL if the driver thinks the texture is
> incomplete, but I didn't have that issue.
>
> Scott
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Re: [osg-users] Modern GLSL and OSG

[Jan Ciger]

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On 24/09/15 00:19, Garth D wrote:
> 
> Hi Christian,
> 
> Many thanks for the interesting suggestion. :)
> 
> My main development environment is Linux-based, with a secondary 
> virtualised Windows development environment. Due to the
> visualization (VirtualBox) I don't believe I can do much in the way
> of development with ANGLE due to its DX backend, at least with my
> current setup.

Um, wouldn't it be far easier to simply ask OSG to create an OpenGL
3.x/4.x core context instead? Then you don't have the legacy stuff
available and don't need to bother with hacks like Angle.

J.
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Re: [osg-users] Modern GLSL and OSG

[Garth D]

Hi Jan,

On 25/09/15 05:18, Jan Ciger wrote:> -BEGIN PGP SIGNED MESSAGE-
> On 24/09/15 00:19, Garth D wrote:
>> Many thanks for the interesting suggestion. :)
>>
>> My main development environment is Linux-based, with a secondary
>> virtualised Windows development environment. Due to the
>> visualization (VirtualBox) I don't believe I can do much in the way
>> of development with ANGLE due to its DX backend, at least with my
>> current setup.
>
> Um, wouldn't it be far easier to simply ask OSG to create an OpenGL
> 3.x/4.x core context instead? Then you don't have the legacy stuff
> available and don't need to bother with hacks like Angle.

Thankyou for the suggestion. :)

I have to admit being unsure how to set the specific context at present.

From what I've read, there'd need to be a glXCreateContextAttribsARB 
call somewhere to create the GL3 context under Linux- and there doesn't 
seem to be one. Skimming the source (I'm presently using OSG 3.2.1, but 
had a peek at 3.4.0) suggests that perhaps this support is only 
available on a Windows build. On the cmake side, OSG_GL3_AVAILABLE in my 
build is off. However, glVersion=4.4 appears in my log during a build.


However, I am probably fine even if I am not grasping things entirely at 
this point. It is something I can experiment with later on, probably on 
my existing Windows build environment. Whether I experiment with ANGLE 
from there or not is something I can weigh up from that point. Thanks 
for the additional input.


I also just noticed that my prior email used "visualization" rather than 
"virtualisation". Whoops. ;} I think I need to place a little less faith 
in spellcheck suggestions.


I'm beginning to suspect that aiming for strict OpenGL 3+ or 4+ might 
not be the best thing for me to concentrate at the moment. I might be 
better off just using it where it helps and leaving a jump to "pure" 
modern GL until a later date.


Cheers,
Garth
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