Bug 48489 – Work around a Mac driver bug in generateMipmap

• Status: RESOLVED
• Resolution: FIXED
• Component: WebGL

[Zhenyao Mo]

If minFilter is not GL_LINEAR_MIPMAP_LINEAR when calling generateMipmap, following draw might show garbage data instead of the proper texture.

[Zhenyao Mo]

Created attachment 72124 [details]
patch

Tested, Worlds of WebGL demo works with this patch in Chromium.

[Kenneth Russell]

Comment on attachment 72124 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=72124&action=review

Excellent work tracking this down. There is one error in the ChangeLog though. Please fix before committing.

> WebCore/ChangeLog:9
> +        (WebCore::WebGLRenderingContext::generateMipmap): Make sure minFilter is set to LINEAR_MIPMAP_LINEAR before generateMipmap, and after the call, set it back to the original value.

This should be NEAREST_MIPMAP_LINEAR.

[Mark Rowe (bdash)]

Can you please add a reference in the code to the bug report about the driver issue?  Without one it’s going to be more difficult to determine whether the underlying issue has been addressed.

[Zhenyao Mo]

(In reply to comment #3)
> Can you please add a reference in the code to the bug report about the driver issue?  Without one it’s going to be more difficult to determine whether the underlying issue has been addressed.

OK, I created a bug for adding reference to bug reports.

https://bugs.webkit.org/show_bug.cgi?id=48528

I want to land this now.  I am working on a test case for the bug report.

[Zhenyao Mo]

Committed r70784: <http://trac.webkit.org/changeset/70784>