using #ifdef GL_SAMPLER_BINDING instead of if (glBindSampler)

[ziocleto]

OpenGL ES (2.0/3.0)

This fixes a pedantic compiler error and encapsulates better OpenGL ES API.

if (glBindSampler) glBindSampler(0, 0);

Fails on Clang5.0+ (C++17) with warning as errors:

error: address of function 'glBindSampler' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]

And equally the "fix":

if (&glBindSampler) glBindSampler(0, 0);

Will fail on GCC 8.1.0+ (and probably earlier)

error: the address of '__glewBindSampler' will never be NULL [-Werror=address]

Using #ifdef GL_SAMPLER_BINDING fixes those errors.

[ocornut]

Will fail on GCC 8.1.0+ (and probably earlier)
error: the address of '__glewBindSampler' will never be NULL [-Werror=address]

I overlooked in your previous message that those are actually warning and not actual errors, it is just that you have error-on-warning, in which case we could possibly disable that warning in the code?
(btw thanks for posting the precise logs!)

I merged this, and then realized that it might be faulty, as some loaders might define all the constants and not bind the functions depending on GL version support.

@matrefeytontias This is a followup to our discussion in #1806, would it be possible to confirm that this is working well with your setup? Aka the #ifdef GL_SAMPLER_BINDING test is evaluating to false and the glBindSampler() call that was crashing in your setup is not called? To double-check you may comment out the #ifdef check and make sure that it DOES crash without it. Thank you!

[ok-what]

Hi, I'm not sure where to say this but I'll comment here as this is about the same issue.
On my setup, with glad and OpenGL 300 ES the code inside the #ifdef gets executed and calling glBindSampler causes a segfault.

[weike20]

300 ES the code inside the #ifdef gets executed and calling glBindSampler causes a segfault.

I have same questions

[jjwebb]

Hi guys, I found this thread through Google because I was having exactly the same issue with the #ifdef code executing and causing a segfault in OpenGL 310 ES. I tracked down the bug and submitted a pull request which fixes this problem. See here:
#3467