glCreateShader call fails with v3.0.2

[9prady9]

I am facing an issue while porting forge visulization library from 2.* version to 3.0.2. I was able to fix the compilation issues, at least I thought so until I saw the runtime issues.

I initially thought it might be due to GetProcAddress I am passing, but I think I am doing it correctly - since the context relevant is current when I call Binding::initialize.

Please have a look at the changes I made to forge at arrayfire/forge#184 The code compiles fine but the glCreateShader calls return 0 always at runtime. Can you please suggest what I might be missing in the migration from 2.* to 3.0.

Thank you,
Pradeep.

[scheibel]

Regarding your PR and its diff, I don't see any issue.

However, you perform calls to both glbinding::Binding::useCurrentContext and glbinding::Binding::initialize. This is not necessary as (1) the initialize takes a parameter that indicates immediate use after initialization (which you seem to want) and (2) the initial useCurrentContext performs an internal initialization as if it was called without function pointer resolve callback.

In conclusion, this double initialization may be a cause for an error, although a preliminary source code check didn't raise anything suspicious.

[9prady9]

@scheibel Thanks for the comments, Will remove the redundant call and let you know how that goes.

[9prady9]

@scheibel It works but there is strange statement printed onto the console. The rendering seems to be fine, but it thinks GLFW is not initialized.

./build/examples/cuda/surface 
The GLFW library is not initialized

Here is the diff of change I did after the PR.

diff --git a/src/backend/opengl/window_impl.cpp b/src/backend/opengl/window_impl.cpp
index fca909d..3f12cd5 100644
--- a/src/backend/opengl/window_impl.cpp
+++ b/src/backend/opengl/window_impl.cpp
@@ -129,9 +129,8 @@ window_impl::window_impl(int pWidth, int pHeight, const char* pTitle,
         mWindow = new wtk::Widget(pWidth, pHeight, pTitle, nullptr, invisible);
     }
     /* Set context (before glewInit()) */
-    MakeContextCurrent(this);
 
-    glbinding::Binding::useCurrentContext();
+    mWindow->makeContextCurrent();
     glbinding::Binding::initialize(mWindow->getProcAddr(), false);
 
     mCxt = mWindow->getGLContextHandle();

The windows show correct rendering and closes fine when I press escape as it should.

I don't see this problem with SDL2. Hence, I don't believe this is issue with glbinding anymore. It either has something to do with glfw or forge itself.

Thanks for you help!