OIT artifacts

[pjcozzi]

Could be an Intel bug: https://code.google.com/p/chromium/issues/detail?id=414280

Could also be our bug: https://twitter.com/pastasfuture/status/511538181691682816

Info on their implementation: http://floored.com/blog/2014/webgl-order-independent-transparency-single-render-target.html

[shunter]

I get a different artifact on OS X 10.9.5 with a Radeon HD 6630M.

The artifacts move around as the camera moves.

[mramato]

FYI, I get similar issues with OIT enabled under Linux using an HD 4000. It does not happen with the same machine on Windows.

[gberaudo]

I have the issue reported by @pjcozzi and @mramato on my machine when OIT is enabled (Cesium 1.5). It disappears when disabling OIT:

scene._oit.isSupported = function() {
    return false;
};

Tested on Ubuntu 14.10:

• https://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=Geometry%20and%20Appearances.html&label=Showcases
• Intel Corporation 4th Gen Core Processor Integrated Graphics Controller [8086:0416](rev 06).
• Mesa DRI Intel(R) Haswell Mobile
• GL_VERSION 3.0 Mesa 10.3.2

What is the consequence of disabling OIT?

[pjcozzi]

@gberaudo instead of using that workaround, set orderIndependentTranslucency to false when constructing Viewer: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Widgets/Viewer/Viewer.js#L217

For the consequence, see: http://cesiumjs.org/2014/03/14/Weighted-Blended-Order-Independent-Transparency/

[gberaudo]

Thank you @pjcozzi.
Added a comment to the Chrome bug https://code.google.com/p/chromium/issues/detail?id=414280#c9.