[vtkusers] VTK 6.3 OpenGL2 - vtkTextActor blurred text when used with vtkFixedPointVolumeRayCastMapper

[Simon ESNEAULT]

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>*
>



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Simon Esneault
Rennes, France
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