[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Public WebGL] Adding internalformat param to all texImage2d variants



On May 16, 2010, at 1:11 PM, Johannes Behr wrote:

> HI,
> 
>>> 
>>> This can be easily done during runtime as part of your standard-shader
>>> but we just have to know it upfront.
>> 
>> Yes, this is the original discussion. But you only need to know the original format because that's how X3D defines it today.
> 
> Right. We only need to know. Can be RGB or RGBA or anything we understand at the end. 
> 
>> In fact X3D is deficient in that, if you have an RGB image and want to use it as an alpha channel you can't.
> 
> Correct for the standard lighting model. But you can use the shader component and your are free to do whatever you want. 
> 
>> X3D has no property to indicate that the image should be stored in texture memory in the requested format. 
>> 
>> My proposal would change the rules of the X3D ImageTexture. You'd have to add a format property, where you specify what format you want the texture to be. There might be some incompatibilities in a small amount of X3D content, but I think you'd have a better ImageTexture spec.
> 
> I don't agree. Putting a extra "format" parameter to the ImageTexture spec would not lead to a better ImageTexture interface:
> 
> - What should this format be if you use the ImageTexture e.g. as shader property ?
> - Source of confusion if the image and format do not match. What should happen if somebody changes the url during runtime ?
> - You can not reuse the ImageTexture with a different format.

If I have an image that is 2 channels (LA) and my shader expects it to be RGB, I won't get reasonable results, right? If so I don't think having the format automatically set is very useful. 

-----
~Chris
cmarrin@apple.com





-----------------------------------------------------------
You are currently subscribe to public_webgl@khronos.org.
To unsubscribe, send an email to majordomo@khronos.org with
the following command in the body of your email: