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Re: [Public WebGL] WEBGL_dynamic_texture extension proposal



A set-top box maker who intends to write a custom app specifically targeted at displaying video is just one of those border use-cases.

I know that there are insurmountable obstacles in making this thing work without some kind of shader semantic change. I wish there wasn't. Because if there was not, you could enjoy nearly instant support by any 3rd party code out there. I would wish to be copy-less to be as popular as possible. I've run personally into problems with copying in a previous project (too slow). But I just don't see how this will be uptaken if it breaks everything.

On Fri, Jul 6, 2012 at 4:14 AM, Mark Callow <callow_mark@hicorp.co.jp> wrote:
I strongly disagree that frameworks can't handle this. As long as the framework provides a way for the application to tell it what type of texture image it wants to use, many frameworks will be able to handle the separate sampler type without major problem. Existing frameworks of course have no mechanism for the app. to indicate the type of texture image so they will require modification.

I also strongly disagree that the cases where a framework (designed for handling dynamic images) would not need to copy are "border-use cases." The impetus for drafting this proposal was a discussion with a set-top box maker who needs to avoid the copy. (Isn't set-top box a ridiculously out-dated _expression_; who has a TV set any more with a top on which anything can be placed?)

Due to the architecture of OpenGL, the only time a check and recompile can be done, if a single sampler type is used, is during the draw call. I don't see any way to change that as uniform values can be changed at any time. Such a check would slow down every application.

Even if a single sampler type is used, the end result will be multiple program binaries that need to be stored so it does not save a whole lot compared to an app. or framework providing multiple shaders up front. I also think it is likely that you'll want a different fragment shader for your video textures anyway, regardless of the sampler type.


Regards

    -Mark
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