Must enable GL_POINT_SPRITE in GraphicsContext3D implementations

• Component: WebGL
• Status: RESOLVED FIXED

[Kenneth Russell]

In order to properly support the gl_PointCoord built-in variable in fragment shaders, it is necessary for the various GraphicsContext3D implementations running on desktop GL to enable the GL_POINT_SPRITE capability. This is similar to the earlier requirement to enable the GL_VERTEX_PROGRAM_POINT_SIZE capability.

Note that testing this in WebKit requires ANGLE issue http://code.google.com/p/angleproject/issues/detail?id=35 to be fixed and the version of ANGLE in WebKit to be updated.

[danceoffwithyourpantsoff]

(In reply to comment #0)
> In order to properly support the gl_PointCoord built-in variable in fragment shaders, it is necessary for the various GraphicsContext3D implementations running on desktop GL to enable the GL_POINT_SPRITE capability. This is similar to the earlier requirement to enable the GL_VERTEX_PROGRAM_POINT_SIZE capability.
> 
> Note that testing this in WebKit requires ANGLE issue http://code.google.com/p/angleproject/issues/detail?id=35 to be fixed and the version of ANGLE in WebKit to be updated.

This was recently fixed in ANGLE and rolled into Chromium, and gl_PointCoord is working now.

However, shaders that use gl_PointCoord still fail to compile in non-chromium WebKit / Safari.

Relevant:

http://code.google.com/p/chromium/issues/detail?id=59763
http://code.google.com/p/angleproject/source/detail?r=448
http://src.chromium.org/viewvc/chrome?view=rev&revision=63084

[Zhenyao Mo]

(In reply to comment #1)
> (In reply to comment #0)
> > In order to properly support the gl_PointCoord built-in variable in fragment shaders, it is necessary for the various GraphicsContext3D implementations running on desktop GL to enable the GL_POINT_SPRITE capability. This is similar to the earlier requirement to enable the GL_VERTEX_PROGRAM_POINT_SIZE capability.
> > 
> > Note that testing this in WebKit requires ANGLE issue http://code.google.com/p/angleproject/issues/detail?id=35 to be fixed and the version of ANGLE in WebKit to be updated.
> 
> This was recently fixed in ANGLE and rolled into Chromium, and gl_PointCoord is working now.
> 
> However, shaders that use gl_PointCoord still fail to compile in non-chromium WebKit / Safari.
> 
> Relevant:
> 
> http://code.google.com/p/chromium/issues/detail?id=59763
> http://code.google.com/p/angleproject/source/detail?r=448
> http://src.chromium.org/viewvc/chrome?view=rev&revision=63084

That's because they are still using an older version of ANGLE.

[Zhenyao Mo]

Created attachment 71574 [details]
patch

Mac port still needs to roll ANGLE for gl_pointCoord to work

[Kenneth Russell]

Comment on attachment 71574 [details]
patch

OK, but see https://bugs.webkit.org/show_bug.cgi?id=48282 ; this only adds code which will need to be fixed later under that bug. Minimally, add a comment to that bug about this new code.

[Zhenyao Mo]

Comment on attachment 71574 [details]
patch

Clearing flags on attachment: 71574

Committed r70666: <http://trac.webkit.org/changeset/70666>

[Zhenyao Mo]

All reviewed patches have been landed.  Closing bug.

[WebKit Review Bot]

http://trac.webkit.org/changeset/70666 might have broken GTK Linux 32-bit Debug