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Re: [Public WebGL] Interest in promoting to draft, and implementing, WEBGL_dynamic_texture



Thanks for the feedback.

On 13/07/30 17:24, Kenneth Russell wrote:
A couple of bugs (haven't gone through the whole spec in detail):

  WDTStream.acquireImage has a different return type in three places
throughout the spec (WDTStreamFrameInfo, boolean, and void).
Should be boolean. Now fixed in my copy. Will appear in the next draft.
  WDTStream.releaseImage() takes different argument types in a couple
of different places (no args, and WebGLTexture).
Should be no args. Also now fixed and will appear in the next draft.
There's some interest in hooking WebRTC MediaStreamTracks directly to
WEBGL_dynamic_texture which raises a question. If the resolution
(width/height) of the source stream changes dynamically, how will that
be reported? Consider MediaStreamTrack as a concrete example.
acquireImage would latch the current frame from the MediaStreamTrack,
and the MediaStreamTrack can report its resolution via
MediaSourceStates. Perhaps it would be "good enough" to go back to the
MediaStreamTrack to query the resolution of the video stream, but
would it be better for WDTStreamFrameInfo to simply contain this
information? That way it's guaranteed to be correct for the most
recently latched frame no matter what the source type.
What is the use case for knowing the image size? Neither EGL_KHR_Stream nor EGL_KHR_stream_consumer_gltexture provide a way to query the size. It has to be done with the producer's API. This suggests the need is not that high.

Without knowing more about the uses, adding the info to WDTStreamFrameInfo seems straightforward. The drawbacks I see are the information being stored twice and that it is the start of a slippery slope giving the temptation to provide more information about the frame, such as its format. This is something we want to avoid as it could lead to applications having to provide a shader per format.

Regards

    -Mark

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