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Re: [Public WebGL] Weird alpha issue.



I'm a bit clueless here; since you're getting this in current nightlies, we do share the same code with WebKit for WebGL texture format conversions, so that can't be the explanation.

Does it make any difference when you go to about:config and toggle the preference webgl.shader_validator?

Benoit

----- Original Message -----
> I have Minefield set up to auto-update and it actually updated just as
> I
> started typing this email - so I guess I have the latest! ...and the
> color is still much darker than in Chrome.
> 
> I took a pair of side-by-side screenshots with the latest versions of
> both browsers:
> 
> http://www.sjbaker.org/tmp/smoke_differences.png
> 
> (It's kinda hard to see the smoke on the Minefield side - but it's
> much
> more obvious in motion).
> 
> If it helps, the texture map is in:
> 
> http://www.sjbaker.org/tmp/Smoke.png
> 
> -- Steve
> 
> 
> 
> On 10/30/2010 11:08 AM, Benoit Jacob wrote:
> > What's your Minefield build? Two weeks ago, I landed important
> > texture fixes that could be related to that. Please try with the
> > latest nightly:
> >
> > http://nightly.mozilla.org/
> >
> > Benoit
> >
> > ----- Original Message -----
> >
> >> I'm running some particle system tests - using an RGBA .png image
> >> with
> >> fuzzy mid-grey translucent smoke puffs. There are lots of particles
> >> layered on top of each other.
> >>
> >> What's odd is that the smoke puff is much lighter in color on
> >> Chrome
> >> than it is on Minefield - even with both browsers running
> >> side-by-side
> >> on the exact same Win7/32bit/nVidia machine displaying the exact
> >> same
> >> scene. Everything else in the scene looks utterly identical in the
> >> two
> >> windows.
> >>
> >> I'm kinda suspecting some funky thing going on with pre-multiplied
> >> alpha. Is someone messing with my texture?
> >>
> >> DETAILS:
> >>
> >> The setup for drawing is:
> >>
> >> gl.enable ( gl.DEPTH_TEST ) ;
> >> gl.depthMask ( false ) ;
> >> gl.enable ( gl.BLEND ) ;
> >> gl.blendFunc ( gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA ) ;
> >>
> >> ...with everything else left at default values.
> >>
> >> The frag shader says:
> >>
> >> float4 color = texture2D ( fire, UV ).rgba * (1.0-smokeAmount) +
> >> texture2D ( smoke, UV ).rgba * smokeAmount ;
> >> color.a *= timeVaryingAlpha ;
> >> gl_FragColor = color ;
> >> }
> >>
> >> ...and in this case, smokeAmount is 1.0 (so we should see only the
> >> smoke
> >> map...and that works) and timeVaryingAlpha varies between 0.0 and
> >> 1.0
> >> as
> >> you'd expect.
> >>
> >> My image 'onload' function says:
> >>
> >> gl.bindTexture ( gl.TEXTURE_2D, texture ) ;
> >> gl.pixelStorei ( gl.UNPACK_FLIP_Y_WEBGL, true);
> >> gl.texImage2D ( gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA,
> >> gl.UNSIGNED_BYTE, image ) ;
> >> gl.generateMipmap ( gl.TEXTURE_2D ) ;
> >> gl.bindTexture ( gl.TEXTURE_2D, null ) ;
> >>
> >> Help!
> >>
> >> -- Steve
> >>
> >> -----------------------------------------------------------
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