Cesium completely broken in Edge

[mramato]

RuntimeError: Program failed to link.  Link log: Varying variable with name "v_logZ" is used in fragment shader, but doesn't exist in vertex shader

@lilleyse is investigating, but @bagnell if you're out there we need you.

[mramato]

bisect claims 0a628db is the first bad commit.

[likangning93]

Adding a czm_vertexLogDepth(); at the end of EllipsoidVS.glsl seems to fix the problem, but the mystery then is why this works in Chrome...

[bagnell]

Fragment shaders that include that GLSL file don't use that varying when computing the depth in the fragment shader. The shader compilers in other browsers were removing it but Edge wasn't.

[oterral]

Hi @bagnell @lilleyse, We have still this bug in 1.46 and 1.45 . When we try to display .vctr 3d tiles.

Here is an example :
https://codepen.io/anon/pen/RJrxYM?editors=0010

Our tilset contains only points.

[hpinkos]

Hi @oterral, I opened #6654 so we can track the problem there instead of on this closed issue. Thanks!