HeatmapLayer throws GL_BLEND with floating-point color attachments requires the EXT_float_blend extension

[christianbalderrama]

Description

Implementing the HeatmapLayer doesn't reflect the heatmap and throws warning in the console see logs below.

Repro Steps

    const layers = [
      new HeatmapLayer({
        id: "heatmaplayer",
        data: [{COORDINATES: [-122.42177834, 37.78346622], WEIGHT: 10}],
        getPosition: d => d.COORDINATES,
        getWeight: d => d.WEIGHT,
      }),
    ];
    return (
      <MapGL ...>
        <DeckGL
            viewState={this.state.viewState}
            initialViewState={this.state.viewState}
            controller={{type: MapController}}
            layers={layers}
            onContextMenu={event => event.preventDefault()}
        />
      </MapGL>
    );

Environment:

• Framework Versions:

    "@deck.gl/aggregation-layers": "^7.2.2",
    "@deck.gl/core": "^7.2.2",
    "@deck.gl/layers": "^7.2.2",
    "@deck.gl/mapbox": "^7.2.2",
    "@deck.gl/react": "^7.2.2",

• Browser Version: Chrome 75.0.3770.142
• OS: Xubuntu 18.04 LTS x64

Logs

2TWFwOjE=:1 [.WebGL-0xc881cd8b300]GL ERROR :GL_INVALID_OPERATION : glDrawArrays: GL_BLEND with floating-point color attachments requires the EXT_float_blend extension

[christianbalderrama]

This console warning shows in the official documentation and does not reflect the heatmaps as well.

[1chandu]

HeatmapLayer is WebGL2 only for now (support for WebGL1 in future releases), but it should print an error message when run under WebGL2.

One possibility is you are using WebGL2, but EXT_float_blend is not supported, if so we have to add explicit check for it. Can you set luma.log.priority=1 in your chrome browser console and refresh the heatmap documentation page, and copy paste logs here? It should log what kind of WebGL context it is using.

To verify if you have the support, can you go to https://webglreport.com/?v=1 and under WebGL1 and WebGL2 tab, see if EXT_float_blend listed?

[1chandu]

Filed a bug to Khronos for clarifying this extension page for WebGL2 support :

[1chandu]

@christianbalderrama , it turns out the EXT_float_blend is not always supported in WebGL2 and this layer requires it. I am making a change to log more meaningful message instead of a crash.