WebGL unbound texture warnings in Chrome

[markpet49]

Description

Several examples (Annotations, DeepPicking and others) display the following WebGL warning in the console:

[.Offscreen-For-WebGL-0x1633cf178600]RENDER WARNING: there is no texture bound to the unit 0

This warning occurs many times and appears to be linked to the mouse cursor scrolling over the canvas.

Operating System and Version

Ubuntu 16.04/Chrome 61

[balhar-jakub]

Confirm

Operating System and Version

Windows 10 / Edge 40

[Beak-man]

Confirmed in Windows 10/Chrome 62

[Beak-man]

This warning appears in the following Examples and Apps:

Examples:

• Annotations
• Atmosphere
• Collada
• GeographicMeshes
• GoToLocation
• KmlExample
• Measurements
• MultiWindow
• Paths
• PickAllShapesInRegion
• PlacemarksAndPicking
• Shapefiles
• StarField
• TriangleMeshes (when hovering the pointer over the meshes)
• Wkt

Apps:

• SubSurface
• USGSSlabs
• USGSWells

All other examples/apps are exempt from this warning. Tested in Chrome 62, Windows 10.

[claudiaifrim]

Confirmed on Linux Mint, Chrome Version 62.0.3202.75 (Official Build) (64-bit)

[pdavidc]

Chrome logs this warning when a WebGL draw call is made that meets two criteria:

1. The bound shader program expects a texture.
2. No texture is bound.

This warning appears in Chrome on all operating systems, and it appears whether or not the shader actually reads from the texture. This behavior is consistent with WebGL Security principles. Read the conclusion of the WebGL Security white paper for details. @kenrussell, a WebGL developer and WorldWindJava collaborator alumnus, explains this in a conversation on the three.js repository.

WebWorldWind drawing code needs to adjust to accommodate Chrome's warnings. We'll bind a small blank texture whenever the bound shader program may use a texture, even if we've disabled the texture read via a uniform variable.