remove OffscreenCanvas to fix errors

[johnnyz2017]

Related issue: N/A

Description

When exporting a model with images to gltf format, an error occurs:
GLTFExporter.js:1134 Uncaught (in promise) TypeError: canvas.toDataURL is not a function
at GLTFWriter.processImage (GLTFExporter.js:1134:27)
at GLTFWriter.processTexture (GLTFExporter.js:1192:17)
at GLTFWriter.processMaterial (GLTFExporter.js:1274:42)
at GLTFWriter.processMesh (GLTFExporter.js:1665:26)
at GLTFWriter.processNode (GLTFExporter.js:1952:27)
at GLTFWriter.processNode (GLTFExporter.js:1974:29)
at GLTFWriter.processScene (GLTFExporter.js:2028:28)
at GLTFWriter.processInput (GLTFExporter.js:2084:10)
at GLTFWriter.write (GLTFExporter.js:437:8)
at GLTFExporter.parse (GLTFExporter.js:120:10)

The easiest solution is to remove OffscreenCanvas and use ordinary canvas uniformly.

[takahirox]

Hi, thanks for the problem report and PR.

Unfortunately I don't think removing OffscreenCanvas is a good solution because we use it to enable the exporter to even run in WebWorkers #23857

Probably finding an alternative of .toDataURL() for OffscreenCanvas is better.

[LeviPesin]

Here is how to do that:
https://stackoverflow.com/a/56495103
I.e. it is await new FileReader().readAsDataURL( await canvas.convertToBlob() ).

[johnnyz2017]

OK, got it.

[donmccurdy]

/cc

• GLTFExporter: Check for document before creating OffscreenCanvas #23998
• Fix GLTFExporter when exporting in GLTF with OffscreenCanvas #24031