[vtkusers] VTK 6.3 OpenGL2 - vtkTextActor blurred text when used with vtkFixedPointVolumeRayCastMapper
Aashish Chaudhary
aashish.chaudhary at kitware.com
Fri Nov 20 08:32:35 EST 2015
Hi Simon,
Thanks! I am okay with merging this change but in general restoring to
previous state is tricky as for that you need to know the previous state. I
think restoring to a default state (which you did) makes more sense.
Although in VTK we don't have clear guideline on this. I am reviewing your
changes..
On Fri, Nov 20, 2015 at 8:26 AM, Simon ESNEAULT <simon.esneault at gmail.com>
wrote:
> Hello,
>
> I've created a merge request for this bug :
> https://gitlab.kitware.com/vtk/vtk/merge_requests/932
>
> The class vtkOpenGLRayCastImageDisplayHelper is changing OpenGL blend
> state, but never restores the state as it was before, resulting in some
> incorrect blend later.
> I don't know if it's the correct fix, but it certainly look like the
> reason for this bug, and it solve the bug here.
> Can someone review this merge ?
>
> Regards
> Simon
>
>
> 2015-11-18 9:38 GMT+01:00 Simon ESNEAULT <simon.esneault at gmail.com>:
>
>> Morning !
>>
>> http://www.vtk.org/Bug/view.php?id=15838
>>
>> Let me know if there is anything I can do to solve this.
>>
>> Simon
>>
>> 2015-11-17 16:50 GMT+01:00 Aashish Chaudhary <
>> aashish.chaudhary at kitware.com>:
>>
>>>
>>>
>>> On Tue, Nov 17, 2015 at 3:36 AM, Simon ESNEAULT <
>>> simon.esneault at gmail.com> wrote:
>>>
>>>> Dear Aashish,
>>>>
>>>> Yes the root cause is probably located in vtkTexturedActor2D, or in
>>>> vtkOpenGLTexture::Load( vtkRenderer* ) which looks like the responsible
>>>> class for loading the texture.
>>>> Shall I fill a bug ?
>>>>
>>>
>>> Yes, please.
>>>
>>> - Aashish
>>>
>>>
>>>> Thanks
>>>> Simon
>>>>
>>>> 2015-11-16 17:49 GMT+01:00 Aashish Chaudhary <
>>>> aashish.chaudhary at kitware.com>:
>>>>
>>>>> I see so its not just related to volume rendering and it seems to be a
>>>>> vtkTextActor2D problem? In that can probably Ken / David Lonie wants to
>>>>> take a look at it. Nonetheless, we will follow up on this bug.
>>>>>
>>>>> - Aashish
>>>>>
>>>>> On Mon, Nov 16, 2015 at 11:12 AM, Simon ESNEAULT <
>>>>> simon.esneault at gmail.com> wrote:
>>>>>
>>>>>> Hello Aashish,
>>>>>>
>>>>>> Thanks !
>>>>>> After doing some test, I realized the patch I've just sent is not the
>>>>>> correct fix at all, because the text is not rendered properly when we don't
>>>>>> use a vtkFixedPointVolumeRayCastMapper anymore.
>>>>>>
>>>>>> I believe the problem is probably larger than this and probably has
>>>>>> nothing to do with the freetype text generation, but more with the
>>>>>> vtkTexturedActor2D rendering part used together with a
>>>>>> vtkFixedPointVolumeRayCastMapper on the new rendering backend, when the
>>>>>> texture has some transparent pixel in it ...
>>>>>>
>>>>>> Attached there is a new example that demonstrate that a vtkTextActor
>>>>>> AND a vtkTexturedButtonRepresentation2D are not correctly drawn in that
>>>>>> case :
>>>>>> - OpenGL1 backend
>>>>>> <http://picpaste.com/pics/OGL1-Texture-okay.1447690100.png> : Transparent
>>>>>> pixel in Texture are correctly drawn
>>>>>> - OpenGL2 backend
>>>>>> <http://picpaste.com/pics/OGL2-Texture-not-okay.1447690272.png> :
>>>>>> Transparent pixel in Texture are not correctly drawn (clamped to white ?)
>>>>>>
>>>>>> The example is more simple than the previous one and does not need
>>>>>> any additional data.
>>>>>>
>>>>>> Hope that helps !
>>>>>> -Simon
>>>>>>
>>>>>> 2015-11-16 16:11 GMT+01:00 Aashish Chaudhary <
>>>>>> aashish.chaudhary at kitware.com>:
>>>>>>
>>>>>>> Simon,
>>>>>>>
>>>>>>> Thanks for the report. I will follow up with other developers on
>>>>>>> this bug.
>>>>>>>
>>>>>>> - Aashish
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Nov 16, 2015 at 6:08 AM, Simon ESNEAULT <
>>>>>>> simon.esneault at gmail.com> wrote:
>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> Trying to solve this problem, I found out that if one call
>>>>>>>> "vtkFreeTypeTools::GetInstance()->DebugTexturesOn();" before to render a
>>>>>>>> string with a vtkTextActor, the text is properly rendered with a yellow dot
>>>>>>>> at the anchor point, and with a transparent gray background.
>>>>>>>> - DebugTexturesOn : http://picpaste.com/pics/Blurred.1447668943.PNG
>>>>>>>> - DebugTexturesOff :
>>>>>>>> http://picpaste.com/pics/Not-Blurred.1447669009.PNG
>>>>>>>>
>>>>>>>> Now digging into the code in vtkFreeTypeTools.cxx, I suspect this
>>>>>>>> is a blending problem. When we activate Texture Debugging, a gray
>>>>>>>> background is first drawn, and after that in the method RenderCharacter(
>>>>>>>> ... ) line 1887; we either blend the rendered text with the background or
>>>>>>>> not.
>>>>>>>>
>>>>>>>> Attached is a diff file that solves the problem for me. I do not
>>>>>>>> really understand why, so maybe a developer with more VTK's knowledge can
>>>>>>>> integrate this properly :)
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Simon
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> 2015-11-13 16:43 GMT+01:00 Simon ESNEAULT <simon.esneault at gmail.com
>>>>>>>> >:
>>>>>>>>
>>>>>>>>> Hi All,
>>>>>>>>>
>>>>>>>>> All vtkTextActor are rendered blurred when using with
>>>>>>>>> vtkFixedPointVolumeRayCastMapper in the same renderer in vtk 6.3 with the
>>>>>>>>> new rendering backend.
>>>>>>>>>
>>>>>>>>> Here are some snapshots :
>>>>>>>>> - OpenGL1
>>>>>>>>> <http://picpaste.com/pics/OGL1-not-blurred.1447428990.png>
>>>>>>>>> - OpenGL2 <http://picpaste.com/pics/OGL2-blurred.1447429027.png>
>>>>>>>>>
>>>>>>>>> Attached some code that reproduces the problem, to be used with
>>>>>>>>> this <https://www.dropbox.com/s/ptqwi0ebv75kt35/volume.zip>
>>>>>>>>> volume. Visible on OSX and Windows to our knowledge, probably on more OS.
>>>>>>>>>
>>>>>>>>> The text is rendered properly when used with the old backend or
>>>>>>>>> when using a vtkGPUVolumeRayCastMapper instead of
>>>>>>>>> the vtkFixedPointVolumeRayCastMapper.
>>>>>>>>>
>>>>>>>>> Shall I feel a bug, is this a known issue ?
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Simon
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> ------------------------------------------------------------------
>>>>>>>>> Simon Esneault
>>>>>>>>> Rennes, France
>>>>>>>>> ------------------------------------------------------------------
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> ------------------------------------------------------------------
>>>>>>>> Simon Esneault
>>>>>>>> Rennes, France
>>>>>>>> ------------------------------------------------------------------
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> *| Aashish Chaudhary | Technical Leader | Kitware Inc.
>>>>>>> *
>>>>>>> *| http://www.kitware.com/company/team/chaudhary.html
>>>>>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> ------------------------------------------------------------------
>>>>>> Simon Esneault
>>>>>> Rennes, France
>>>>>> ------------------------------------------------------------------
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>>
>>>>> *| Aashish Chaudhary | Technical Leader | Kitware Inc.
>>>>> *
>>>>> *| http://www.kitware.com/company/team/chaudhary.html
>>>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> ------------------------------------------------------------------
>>>> Simon Esneault
>>>> Rennes, France
>>>> ------------------------------------------------------------------
>>>>
>>>
>>>
>>>
>>> --
>>>
>>>
>>>
>>> *| Aashish Chaudhary | Technical Leader | Kitware Inc.
>>> *
>>> *| http://www.kitware.com/company/team/chaudhary.html
>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>
>>
>>
>>
>> --
>> ------------------------------------------------------------------
>> Simon Esneault
>> Rennes, France
>> ------------------------------------------------------------------
>>
>
>
>
> --
> ------------------------------------------------------------------
> Simon Esneault
> Rennes, France
> ------------------------------------------------------------------
>
--
*| Aashish Chaudhary | Technical Leader | Kitware Inc. *
*| http://www.kitware.com/company/team/chaudhary.html
<http://www.kitware.com/company/team/chaudhary.html>*
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