gl.Init() panics cause of glewExperimental

[go-gl-legacy]

gl.Init() panics cause of glewExperimental

[pwaller]

Can you give a complete stack trace?

[vova616]

C:/Users/X/AppData/Local/Temp/2/bindist012168375/go/src/pkg/runtime/panic.c:229 (0x4126b4)
C:/Users/X/AppData/Local/Temp/2/bindist012168375/go/src/pkg/runtime/panic.c:487 (0x412da4)
C:/Users/X/AppData/Local/Temp/2/bindist012168375/go/src/pkg/runtime/os_windows.c:303 (0x41195f)
E:/Users/X/AppData/Local/Temp/go-build207485643/github.com/go-gl/gl/_obj/attriblocation.cgo1.go:2339 (0x4c74c2)
E:/GO/Projects/src/github.com/vova616/GarageEngine/engine/Engine.go:386 (0x43cf11)
com/vova616/GarageEngine/engine.initGL: gl.Init()
E:/GO/Projects/src/github.com/vova616/GarageEngine/engine/Engine.go:176 (0x43a296)
com/vova616/GarageEngine/engine.StartEngine: if err = initGL(); err != nil {
E:/GO/Projects/src/github.com/vova616/GarageEngine/main.go:65 (0x4012a4)
Start: engine.StartEngine()
C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist012168375/go/src/pkg/runtime/proc.c:1223 (0x416030)

[pwaller]

I'm at a loss. Unfortunately we don't (currently) have any windows developers so aren't in a position to debug it. It was enabled by default on the basis that it shouldn't have any negative effects for users. Maybe we should revisit that decision and make it a controllable parameter?

On the other hand, it could be viewed as a glew (or perhaps driver) bug. @vova616, are you in a position to debug further by trying to reproduce it with a C/C++ program?

It might be worth shooting an e-mail to the glew mailing list to ask if they know what's going on, but I suspect that without an easily reproducible example they won't run with it.

[vova616]

I think its cgo bug, I checked this simple program and it worked http://play.golang.org/p/RcmVDpwPUn

I think this is what happening, glewExperimental is not initialized so the cgo tries to take an address of uninitialized value.
This will crash:
http://play.golang.org/p/ShhdPD1kln

This wont crash:
http://play.golang.org/p/uMSbkMY_vF

I just checked and if you will make a C function that changes glewExperimental it wont crash, exp:
http://play.golang.org/p/fhsCLxolW4

[pwaller]

Thanks for following up! Would you be willing to make a pull request which calls SetExperimental as you demonstrated, instead?

[vova616]

Sure, here
go-gl/gl#101

[pwaller]

Aweomse, thanks! I'll review it tomorrow since our automated tests are failing. Sorry for the delay.

[vova616]

np :)