Bug 148930 – [WebGL] Return correct values for GL_STENCIL_VALUE_MASK and GL_STENCIL_WRITE_MASK

• Component: WebGL
• Status: RESOLVED WONTFIX

[Jinyoung Hur]

n

[Jinyoung Hur]

It seems that ANGLE clamps GL_STENCIL_VALUE_MASK, GL_STENCIL_BACK_VALUE_MASK, GL_STENCIL_WRITEMASK and GL_STENCIL_BACK_WRITEMASK values into max integer, which results in the value change(0xffffffff --> 0x7fffffff) unintentionally.

[Jinyoung Hur]

Created attachment 260737 [details]
Patch

[Jinyoung Hur]

Without this patch, fast/canvas/webgl/gl-get-calls.html fails on ANGLE backed OpenGL ES  platform.

[Dean Jackson]

Comment on attachment 260737 [details]
Patch

We can apply this in WebKit, but you really need the change to be made in ANGLE. Also, is there a way to test this?

[Jinyoung Hur]

(In reply to comment #4)
> Comment on attachment 260737 [details]
> Patch
> 
> We can apply this in WebKit, but you really need the change to be made in
> ANGLE. Also, is there a way to test this?

Ok then, I think it would be safe to commit this patch after landed on ANGLE project first.

I believe there is no way to test this because no ports are using ANGLE as its OpenGL implementation but mine.
My team's port is using ANGLE backed OpenGL APIs so I could find this bug.

Anyway, thanks for review!

[Jinyoung Hur]

ANGLE seems implemented correctly based on the OpenGL ES 3.0 spec.
So this patch should be abandoned.

Instead, I'm trying to modify fast/canvas/webgl/gl-get-calls.html at https://bugs.webkit.org/show_bug.cgi?id=149174

[Jinyoung Hur]

(In reply to comment #6)
> ANGLE seems implemented correctly based on the OpenGL ES 3.0 spec.
> So this patch should be abandoned.
> 
> Instead, I'm trying to modify fast/canvas/webgl/gl-get-calls.html at
> https://bugs.webkit.org/show_bug.cgi?id=149174

Review from an ANGLE people.
https://chromium-review.googlesource.com/#/c/299564/