1082248 - Skip redundant deferred texture image initialization when doing full-image updates

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: Avoid some redundant deferred texture image initialization

bjacob>       jgilbert: while writing this patch, i ran across an optimization opportunity that just changed from "not important" to "very important"
jgilbert>     oh?
bjacob>       jgilbert: if you have a texture with uninitializated image data, and you do a texSubImage on it, that triggers the "deferred initialization" code, which will initialize it using either a glClear or calloc+upload if glClear is not applicable. It's potentially expensive either way.
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bjacob>       jgilbert: that used not to matter much, because that was an uncommon usage pattern,
ick   Callek_disconnected is now known as Callek.
bjacob>       jgilbert: but now with texStorage+texSubImage that becomes the standard usage pattern --- and even the *only* one for 3d textures
jgilbert>     right
jgilbert>     we need to special-case full-image texSubImages
bjacob>       jgilbert: so the easy optimization to do here is, if texSubImage is covering the whole image, skip deferred init
bjacob>       exactrly
jgilbert>     yep, definitely
bjacob>       jgilbert: writing patch (just a few lines)
jgilbert>     yeah, it should be

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=0cbba5eacc89

Comment 2

[Benoit Jacob [:bjacob] (mostly away)]

Had a simple mistake; not worth another review cycle, new try:
https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=2b0ab8963141

Comment 3

[Benoit Jacob [:bjacob] (mostly away)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/1e5f45339d3f

Comment 4

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/1e5f45339d3f