[x3d-public] Background static image and dds

Andreas Plesch andreasplesch at gmail.com
Mon Aug 5 18:32:53 PDT 2019


I agree, a dedicated BackgroundImage node may be more appropriate rather
than layering on top of Background. Sounds like a pretty obvious and
straightforward spec. enhancement to me since all the functionality is
already there, only in separate places. Thinking ahead, there would be need
to be a rule of what to do when both Background and BackgroundImage are
provided.

The simple feature A) of just having static, fixed image as a backdrop is
also very useful. Here is an example:

https://codepen.io/anon/pen/ZgXPVq?editors=1000

-Andreas

On Mon, Aug 5, 2019 at 6:44 PM Michalis Kamburelis <michalis.kambi at gmail.com>
wrote:

> Ah, sorry, I just realized that you meant that X3DOM supports also
> cubemaps in Background node. This is indeed not something in the spec (and
> CGE doesn't do it). I think it could be useful to have an alternative to
> Background node like BackgroundImage that contains a single field like
> "image" of type "X3DEnvironmentTextureNode". One could place there any
> cubemap (ImageCubeMapTexture with DDS or KTX, ComposedCubeMapTexture with 6
> images or even GeneratedCubeMapTexture).
>
> Currently we have Background and TextureBackground
> nodes, TextureBackground is an improvement (has 6 texture nodes instead of
> 6 MFString urls, so it's more versatile) but still you cannot just provide
> one texture with 6 sides (which would be possible with
> X3DEnvironmentTextureNode).
>
> Best regards,
> Michalis
>
> wt., 6 sie 2019, 00:35 użytkownik Michalis Kamburelis <
> michalis.kambi at gmail.com> napisał:
>
>>
>> Andreas Plesch <andreasplesch at gmail.com> wrote:
>>
>>> X3DOM currently has two useful but not spec. compliant features for its
>>> Background node.
>>>
>>> A) support for static, single image background
>>>
>>> If only a backUrl image is provided, it is used as static backdrop which
>>> stays fixed, eg. is not a part of a cube map texture.
>>> The same effect can be achieved with web page css styling, although
>>> sometimes it is advantageous to have a static background rendered with gl.
>>>
>>> B) support for cubemaps in dds format
>>>
>>> dds is a popular texture format which is well defined by MS:
>>>
>>> https://docs.microsoft.com/en-us/windows/win32/direct3ddds/dx-graphics-dds
>>> dds has built in support for cubemaps and is compact and portable.
>>> x3dom understands dds format for an image provided for a cube map.
>>> Support for additional texture formats may be out of scope for X3D.
>>> There may be other Mantis reports on texture formats.
>>>
>>
>> I think B) is already in the specification of ImageCubeMapTexture , see
>>
>>>
>> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/env_texture.html#ImageCubeMapTexture
>> . View3dscene / Castle Game Engine support it too (
>> https://castle-engine.io/x3d_implementation_cubemaptexturing.php ) and I
>> would expect that most other browsers that claim support for ImageCubeMapTexture
>> do too :)
>>
>> BTW, KTX is in some ways a better alternative to DDS, with a clear
>> specification from Khronos. CGE also supports it (although not *yet* for
>> cubemaps), and I would encourage anyone who supports DDS to look into
>> providing KTX support as alternative. See
>> https://castle-engine.io/x3d_implementation_texturing.php#section_ktx
>> and https://github.com/michaliskambi/x3d-tests/wiki/KTX .
>>
>> Best regards,
>> Michalis
>>
>

-- 
Andreas Plesch
Waltham, MA 02453
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