Segfault when uploading vertex data

[arthurjdam]

Referencing https://github.com/PAIR-code/deeplearnjs/issues/234, I'm attempting to add node-webgl as a server-side drop-in replacement in deeplearn.js. I've added the (pretty straight-forward) bindings to replace the WebGLRenderContext and extensions, however, I'm getting an error when binding vertexAttrib buffers, not sure why. Commenting out bindVertexBufferToProgramAttribute for clipSpacePos (gpgpu_util.ts:185) will make it -at least not throw errors- but obviously breaks the engine. Per WebGL_and_OpenGL_Differences I've switched the vertex-data to be uploaded into attribute number 0, but without much success. Any ideas/suggestions as to how I should proceed and/or debug?

Relevant branch: https://github.com/arthurjdam/deeplearnjs/tree/feature-headless-gl

Error (not very helpful, since it's just the segfault when drawing elements):

Status: Using GLEW 2.1.0
Status: Using GLEW 2.1.0
Status: Using GLEW 2.1.0
0
Status: Using GLEW 2.1.0
PID 27244 received SIGSEGV for address: 0x0
0   segfault-handler.node               0x00000001037f0168 _ZL16segfault_handleriP9__siginfoPv + 280
1   libsystem_platform.dylib            0x00007fff57b48f5a _sigtramp + 26
2   ???                                 0x0000000000000000 0x0 + 0
3   GLEngine                            0x00007fff3a587436 glDrawElements_Exec + 961
4   webgl.node                          0x0000000103ddb8dc _ZN5webgl12DrawElementsERKN3Nan20FunctionCallbackInfoIN2v85ValueEEE + 196
5   webgl.node                          0x0000000103dd687b _ZN3Nan3impL23FunctionCallbackWrapperERKN2v820FunctionCallbackInfoINS1_5ValueEEE + 136
6   node                                0x00000001001d08a4 _ZN2v88internal25FunctionCallbackArguments4CallEPFvRKNS_20FunctionCallbackInfoINS_5ValueEEEE + 430
7   node                                0x0000000100219e8b _ZN2v88internal12_GLOBAL__N_119HandleApiCallHelperILb0EEENS0_11MaybeHandleINS0_6ObjectEEEPNS0_7IsolateENS0_6HandleINS0_10HeapObjectEEESA_NS8_INS0_20FunctionTemplateInfoEEENS8_IS4_EENS0_16BuiltinArgumentsE + 775
8   node                                0x00000001002195ae _ZN2v88internalL26Builtin_Impl_HandleApiCallENS0_16BuiltinArgumentsEPNS0_7IsolateE + 259
9   ???                                 0x000030b9e4e0463d 0x0 + 53574966986301