Classification example broken under WebGL 2

[kring]

The Classification Sandcastle example works fine under WebGL1. However, when I switch to WebGL2 by changing the first lines to:

var viewer = new Cesium.Viewer('cesiumContainer', {
    terrainProvider: Cesium.createWorldTerrain(),
    contextOptions: {
        requestWebgl2: true
    }
});

The classification no longer works correctly.

WebGL1

WebGL2

Chrome, Windows 10, renderer: ANGLE (NVIDIA GeForce GTX 1650 Direct3D11 vs_5_0 ps_5_0)

[kring]

Same behavior in Firefox and with my laptop's integrated GPU (ANGLE (Intel(R) UHD Graphics 630 Direct3D11 vs_5_0 ps_5_0).

[mramato]

Lots of stuff is broken under WebGL2, it's going to take a concerted effort to fix/validate/maintain it and given the current WebGL2 adoption rate, it hasn't been a priority.

[aboutqx]

From https://caniuse.com/#search=webgl2 with 74.31% usage, it seems that webgl2 is ready to be commonly used.

[mramato]

@aboutqx thanks for the link. I didn't realize caniuse provided usage stats. The stats we previously had indicated it was much lower. @lilleyse weren't you looking for a source for this last week? (click the link and look in the upper right).

[lilleyse]

Ah cool, I wish it could break down support by WebGL extension but it's better than nothing.

[lilleyse]

Actually I take that back. See https://caniuse.com/#search=EXT_frag_depth

[mramato]

Yeah, caniuse is awesome, I just never noticed the stats in the upper right before. Pretty sad that frag depth is that low. Is an extension still needed for it in WebGL2?

[lilleyse]

frag depth is core in WebGL 2 (and probably others)

74.31% support of WebGL 2 kinda makes a much better case for switching if we can get all the features that were previously WebGL 1 extensions.

[mramato]

frag depth is core in WebGL 2 (and probably others)

Stuff like this is what I'm most excited about, a lot of mobile devices that can support extensions like this don't, but their WebGL2 implementation does, so it's a big win for Cesium.

[kring]

Zero support for WebGL2 on Safari, though, which is probably irrelevant on desktop but a problem on iOS. 😠

[OmarShehata]

I'm closing this since CesiumJS does not officially support WebGL 2, but it is on the roadmap, so we can consolidate known bugs and discussion in this issue: #797 (comment).