[Wrapper] error handling

[tonitch]

Most OpenGL functions can return errors, but they have to be handled manually.

https://www.khronos.org/opengl/wiki/OpenGL_Error

Should the wrapper handle this?

I think it could be cool to have the functions return the error directly if it happens.

My idea is to have a wrapper around each binding call that would do 1) empty the error queue 2) execute the opengl function 3) check if there is a new error and, if so return it.

This is quite the major change in the wrapper, so I want to know what you think about it before doing so.

[hazeycode]

I don't think this is a good idea. Unless we can somehow make it easy to disable this. We cannot make assumptions about driver behaviour or perf impact of glGetError. Zig errors are meant for modelling runtime errors in production but this would be trying to use them solely in debug builds. Even in debug it may be desirable to disable as to not upset performance characteristics.

I would recommend using an error message callback with @breakpoint instead for performance and convenience. From the article:

This method avoids the need to sprinkle expensive and code-obfuscating glGetError() calls around your application to catch and localize the causes of OpenGL errors (and the need to conditionally compile them into debug builds to avoid the performance hit in optimized builds). The feature can even ensure that message callback functions are invoked on the same thread and within the very same call stack as the GL call that triggered the GL error (or performance warning).

I think using an error message callback alongside a graphics debugger serve the user better than employing error sets here.

Perhaps we could provide opt-in "default" message callbacks though.

[basdxz]

I agree with @hazeycode here. To start with, the impact of glGetError is measurable. Not only that, but most of the common errors are actually prevented by the wrapper as-is. As they usually involve using the incorrect enum value or parameter, rather than a state issue.

[deccer]

glGetError is also something you should avoid if you can. it is not even properly used.

I'm ignoring Apple here on purpose because thats the worst platform to run opengl on anyway.

If you can, (there is no excuse not to anyway) target the latest version of OpenGL and use glDebugMessageCallback. (that one is also awailable via an extension for older versions)

But again, its just a stupid wrapper, dont overcomplicate it as mentioned here zig-gamedev/zig-gamedev#674