882890 - WebGL : vertex attribute array 0 should be disable by default

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Guillaume Abadie]

vertex attribute array 0 should be disable by default

Comment 1

[Guillaume Abadie]

Attachment: patch

patch fixing the issue and get passing a WebGL conformance test 1.0.2

Comment 2

[Kelsey Gilbert [:jgilbert]]

Comment on attachment 762323 [details] [diff] [review]
patch

Review of attachment 762323 [details] [diff] [review]:
-----------------------------------------------------------------

This doesn't fix what you say it fixes. Rather, it just pretends that the GL state is set properly. Is there a reason we can't just use the driver's value?

Comment 3

[Guillaume Abadie]

Actually it fix it :

In the WebGL conformance test https://www.khronos.org/registry/webgl/conformance-suites/1.0.2/conformance/state/gl-get-calls.html , it fix the only one FAIL remaining "context.getVertexAttrib(ii, context.VERTEX_ATTRIB_ARRAY_ENABLED) should be false. Was true.". This test just check if all vertex attribute are disable right after the WebGL context creation.

Actually, desktop OpenGL driver don't draw anything when the vertex attribute 0 is disable. But WebGL specifications authorize to draw with the vertex attribute 0 disabled. Therefor the WebGL layer always enable it, and fake the disable action of it. But this fake technique has been forgotten in that function. So this patch fix it, passing and the conformance test. That why this patch is very tiny.

Comment 4

[Kelsey Gilbert [:jgilbert]]

Alright, please leave a comment there saying as much.

Comment 5

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

(In reply to Jeff Gilbert [:jgilbert] from comment #2)
> Comment on attachment 762323 [details] [diff] [review]
> patch
> 
> Review of attachment 762323 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> This doesn't fix what you say it fixes. Rather, it just pretends that the GL
> state is set properly. Is there a reason we can't just use the driver's
> value?

The OpenGL value is different from the WebGL one because of vertex attrib 0 on desktop GL.

Comment 6

[Guillaume Abadie]

Attachment: patch for landing

enhancing the patch comment for landing

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/9b5816c7fa6e

Comment 8

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 763547 [details] [diff] [review]
patch for landing

Please just use checkin-needed in the future :)

Comment 9

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/9b5816c7fa6e