Scattergl markers are not rendered but you can hover over them

[rhamner]

The behavior here is similar to a previous bug I hit (issue 2999) but that bug's reproducing case no longer reproduces for me so I think this might be the same behavior from a different issue.

If I plot a large number of markers with scattergl, it works fine. If I then plot a subset, it does not. The transition point seems to be ~100k markers. That is, once I plot more than ~100k, plotting below ~100k shows the issue.

Here is a really simple reproducing example:

https://codepen.io/rhamner/pen/XQpRbx

If I use 'scatter' instead of 'scattergl' it works fine, but our actual use case is much larger than 100k points so scatter doesn't work.

The browser generates hundreds of these warnings:

[.WebGL-00000080DCBEE1F0]GL ERROR :GL_INVALID_OPERATION : glDrawArrays: attempt to access out of range vertices in attribute 0

I'm using chrome Version 73.0.3683.103 (Official Build) (64-bit). This specific sample code does not show the issue in firefox, but I do hit the issue in firefox with our actual code and I'm not sure why.

[archmoj]

our actual use case is much larger than 100k points so scatter doesn't work.
@rhamner it is close to how many points?

[rhamner]

@archmoj on the order of 1M. The actual one where I noticed this originally was ~300k points dropping down to ~15k points.

[etpinard]

Right the cross-over should be at 1e5 pts. Something must be up with point-cluster. Note that we never cluster x/y scattergl data below 1e5 pts.

plotly.js/src/traces/scattergl/index.js

Lines 77 to 85 in 636a356

	if(hasTooManyPoints && (xa.type !== 'log' && ya.type !== 'log')) {
	// FIXME: delegate this to webworker
	stash.tree = cluster(positions);
	} else {
	var ids = stash.ids = new Array(len);
	for(i = 0; i < len; i++) {
	ids[i] = i;
	}
	}

[etpinard]

More info -> gl-vis/regl-scatter2d#19

[rhamner]

Scanning through that...if I understood correctly, newPlot will not show this issue? I tried it out in that codepen I included and the issue goes away. Is that a valid stopgap?

[etpinard]

cc #2334

[etpinard]

cc #3405

[archmoj]

This issue appears to be (going to be) fixed (in the next release v.1.49.0) after bumping [email protected] which uses [email protected] in #3904.
Codepen

[etpinard]

after bumping [email protected] which uses [email protected] in #3904.

I doubt it. We shouldn't be calling point-cluster from regl-scatter. Our call to point-cluster is here:

plotly.js/src/traces/scattergl/calc.js

Line 67 in d75e956

stash.tree = cluster(positions);

[archmoj]

But that line is not called in the codepen demonstrating the issue.

[etpinard]

But that line is not called in the codepen demonstrating the issue.

Right, because your https://codepen.io/MojtabaSamimi/pen/VJddPx has (only) 1e4 points. See https://codepen.io/etpinard/pen/EBRpqz which has 1e5 points - and appears buggy still.

[archmoj]

@rhamner
A candidate fix illustrated in this demo.

[archmoj]

Closed by #4323 .

[rhamner]

Thanks