add device_type inference to gl backend

[jackmott]

A first pass at inferring the device type. If we see "intel" in the device string we can be confident that it is an integratedgpu. If we see "nvidia", "ati", or "amd" it is either going to be discrete or have performance much better than the intel integrated gpu. Otherwise we set device_type to Other since we really have no idea.

Fixes #2593
PR checklist:

• make succeeds (on *nix)
• make reftests succeeds
• tested examples with the following backends:gl
• rustfmt run on changed code

[jackmott]

Maybe this whole idea is no good. Intel has discrete cards coming:
https://www.tomshardware.com/news/intel-discrete-gpu-2020-raja,37289.html

Should we always say Other? Should we add an Unknown to the Device_Type enum? This would break from the Vulkan API though.

[kvark]

Note that AMD also has APUs, which are integrated... I wonder we can do a more precise matching of the adapter name to figure this out. As for the current PR, I don't feel strongly either way. Anyone got a strong opinion here?

[grovesNL]

Not really, I'd slightly prefer a stronger heuristic than vendor.

[jackmott]

I'm going to do some research on vendor/version/renderer strings and see if we can do better. I've got quite a few computers here to survey.

[jackmott]

I've got a simple command line program that will print renderer vender and version:
https://github.com/jackmott/rustglstats

I've started compiling results for computers I have access to:
https://docs.google.com/spreadsheets/d/1va19XlGv9VuUEF99ekkWhDoTroYOp-QRAIU457lAnM4/edit?usp=sharing

if any of you want to add to it or pass this around please do

[kvark]

Could also use glxinfo that is included by default in Linux. There is also a database in https://opengl.gpuinfo.org/

[jackmott]

I figured something like that would exist already

[jackmott]

if anyone has an "IGP" or "nForce" nvidia card to run glxinfo on I'd like to see the output. the opengl database doesn't have any examples.

[kvark]

any reason to not match just `"radeon hd "?

[jackmott]

yes, most radeon hd gpus are not integrated

[kvark]

oh, ok
let's proceed!
bors r+

[bors]

Build succeeded

• continuous-integration/travis-ci/push