Supported image files about gltf

[tparisi]

Patrick,

I think BMP is OK to ignore, but are you saying that .gif is hard to deal
with? Obviously it's a native web format.

On Tue, Mar 19, 2013 at 12:12 PM, Patrick Cozzi [email protected]:

Ignoring texture compression for the moment, I currently wrote the spec to
support the following image formats because these formats are natively
supported by modern web browsers: .jpg, .png, .bmp, and .gif.

However, I see little value in supporting .bmp and .gif especially since
it could increase the burden for OpenGL and OpenGL ES users using C++.

Do we agree that just .jpg and .png are sufficient (again, ignoring
compression)?

Also, I believe the spec should explicitly mention the formats since, for
example, COLLADA allows for any image format, which makes it really hard to
write a renderer and know it is going to work on all models.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/10
.

Tony Parisi [email protected]
CTO at Large 415.902.8002
Skype auradeluxe
Follow me on Twitter! http://twitter.com/auradeluxe
Read my blog at http://www.tonyparisi.com/

Read my book! WebGL, Up and Running
http://shop.oreilly.com/product/0636920024729.do
http://www.amazon.com/dp/144932357X

[pjcozzi]

gif is not hard for web browsers (assuming we ignore animated gif), but it could be painful for developers in other languages. Does it really provide value over png or jpg?

[tparisi]

Only when animated. When animated, it's hugely valuable and a lot of people
use it in their web pages and games, still.

Which, now that actually gets me thinking about another thing. WebGL lets
you put video on a texture. My applications are using that a lot, I have
several places where we are mapping video onto surfaces for movie
thumbnails, videos playing on a virtual computer screen and so on. Given
that WebGL is our primary target it would be BAD if we didn't support
whatever texture types WebGL supports.

Maybe this is a job for profiles?

Tony

On Tue, Mar 19, 2013 at 12:31 PM, Patrick Cozzi [email protected]:

gif is not hard for web browsers (assuming we ignore animated gif), but it
could be painful for developers in other languages. Does it really provide
value over png or jpg?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/10#issuecomment-15137709
.

Tony Parisi [email protected]
CTO at Large 415.902.8002
Skype auradeluxe
Follow me on Twitter! http://twitter.com/auradeluxe
Read my blog at http://www.tonyparisi.com/

Read my book! WebGL, Up and Running
http://shop.oreilly.com/product/0636920024729.do
http://www.amazon.com/dp/144932357X

[pjcozzi]

We want to do videos, but real videos, not with animated gifs. We haven't thought about it much yet, but it's possible that it would only be in the WebGL profile or a separate extension.

[RemiArnaud]

I think image conversion is out of scope for the glTF spec

-----Original Message-----
From: Patrick Cozzi [email protected]
Date: Tue, 19 Mar 2013 12:12:47
To: KhronosGroup/[email protected]
Reply-To: KhronosGroup/glTF [email protected]
Subject: [glTF] Supported image files (#10)

Ignoring texture compression for the moment, I currently wrote the spec to support the following image formats because these formats are natively supported by modern web browsers: .jpg, .png, .bmp, and .gif.

However, I see little value in supporting .bmp and .gif especially since it could increase the burden for OpenGL and OpenGL ES users using C++.

Do we agree that just .jpg and .png are sufficient (again, ignoring compression)?

Also, I believe the spec should explicitly mention the formats since, for example, COLLADA allows for any image format, which makes it really hard to write a renderer and know it is going to work on all models.

---

Reply to this email directly or view it on GitHub:
#10

[fabrobinet]

If that can be in the SPEC it should be per profile. But not sure if we can/should be aware of all images format here either. We just need to make sure that for a given profile we can convert to what's is known to be the best.

[tparisi]

Agree

On Tue, Mar 19, 2013 at 3:31 PM, Rémi Arnaud [email protected]:

I think image conversion is out of scope for the glTF spec

-----Original Message-----
From: Patrick Cozzi [email protected]
Date: Tue, 19 Mar 2013 12:12:47
To: KhronosGroup/[email protected]
Reply-To: KhronosGroup/glTF [email protected]
Subject: [glTF] Supported image files (#10)

Ignoring texture compression for the moment, I currently wrote the spec to
support the following image formats because these formats are natively
supported by modern web browsers: .jpg, .png, .bmp, and .gif.

However, I see little value in supporting .bmp and .gif especially
since it could increase the burden for OpenGL and OpenGL ES users using
C++.

Do we agree that just .jpg and .png are sufficient (again, ignoring
compression)?

Also, I believe the spec should explicitly mention the formats since, for
example, COLLADA allows for any image format, which makes it really hard to
write a renderer and know it is going to work on all models.

---

Reply to this email directly or view it on GitHub:
#10

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/10#issuecomment-15147688
.

Tony Parisi [email protected]
CTO at Large 415.902.8002
Skype auradeluxe
Follow me on Twitter! http://twitter.com/auradeluxe
Read my blog at http://www.tonyparisi.com/

Read my book! WebGL, Up and Running
http://shop.oreilly.com/product/0636920024729.do
http://www.amazon.com/dp/144932357X

[fabrobinet]

Related to #18

[pjcozzi]

Are we in agreement that the glTF profile should determine what image formats are allowed, and that the WebGL 1.0 profile should only allow png and jpg (again, ignoring compressed textures right now).

The spec cannot leave this open-ended because then it will be impossible to write a renderer that works with all glTF content because a web browser, for example, doesn't support tiff files.

[RemiArnaud]

That's correct.

This said, this also implies the converter need to convert all the images
it gets into the allowed image format... otherwise it would not be
compliant to the spec?

On Wed, Mar 20, 2013 at 5:14 AM, Patrick Cozzi [email protected]:

Are we in agreement that the glTF profile should determine what image
formats are allowed, and that the WebGL 1.0 profile should only allow pngand
jpg (again, ignoring compressed textures right now).

The spec cannot leave this open-ended because then it will be impossible
to write a renderer that works with all glTF content because a web browser,
for example, doesn't support tiff files.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/10#issuecomment-15171997
.

[mramato]

One thing I'll add to this conversation, that some people may not be aware of. The HTML img tag does not have any specific formats defined. So even if a web browser only supported ppm images, it would be considered 'to spec'. In the grand scheme of things, I think it's a good call to have specific formats hard-coded into the profile, and jpg and png are good choices, but as newer formats, like webP, begin to take hold, it should allow for the possibility of adding additional formats in future profiles.

Meanwhile, the new video element has a different take. While there are no specific video formats in the spec, HTML can specify multiple formats for the same video element and the browser chooses whichever one it supports the best. It will probably be even harder to specify specific formats for video textures because of this, plus browser support for video is still all over the place.

[RemiArnaud]

FYI - There is a http method for asking for specific format, it is in the header, called media-range.

[pjcozzi]

This said, this also implies the converter need to convert all the images it gets into the allowed image format... otherwise it would not be compliant to the spec?

Yeap - that is the plan.

[fabrobinet]

@mramato you have a very good point, new image format may come up and we do not want to be blocked by early choices. One way to handle this would be add them in minor revision of the spec.
@pjcozzi we can start with just jpg and png as you suggest. and open up this limitation as mentioned above in other spec revision if really needed.

[pjcozzi]

OK with me. We also also add extensions if they are needed before minor revisions.

[pjcozzi]

Updated schema.