Add OpenGL 4.5

[heyx3]

I haven't explicitly tested each new function/constant, but here is a quick rundown of my process to add this stuff:

1. Refer to the OpenGL wiki to see what extensions were made core in OpenGL 4.5: https://www.khronos.org/opengl/wiki/History_of_OpenGL#OpenGL_4.5_.282014.29

• ARB_clip_control
• ARB_cull_distance
• ARB_ES3_1_compatibility
• ARB_conditional_render_inverted
• ARB_derivative_control
• ARB_direct_state_access
• ARB_get_texture_sub_image
• KHR_robustness
• ARB_shader_texture_image_samples
• ARB_texture_barrier

2. For each extension, look at their "new tokens" and "new procedures and functions" sections.

3. Add all new "tokens" to glConstants.jl

4. Add all new functions to glFunctions.jl

If this gets merged in, I intend on doing OpenGL 4.6 next.

[heyx3]

By the way, are the export statements necessary for glConstants.jl? A quick glance over the @GenEnums macro shows that it ends with an export expression:

esc(Expr(:block, enumtype, tmp..., Expr(:export, :($(enumName)))))

[heyx3]

For reference, if anybody wants to use OpenGL 4.4 through 4.6 right away, I have a branch in my fork that implements those changes. I haven't checked if anything's missing from 4.3 and below.

https://github.com/heyx3/ModernGL.jl/tree/v4.6

[SimonDanisch]

Cool stuff :) is this ready to merge?

[heyx3]

I'll try to go over the constants and functions one more time today to verify that they're correct. The DSA ones are a big pain just because there's so many new functions!

The test does still run successfully, so there's no compilation errors or anything.

[heyx3]

Went over it again, and it looks correct to me.

[SimonDanisch]

Awesome, thank you! At some point it would be worth to wrap these automatically with Clang.jl...
When we wrapped these, Clang wasn't in a great state, but now it seems to be fairly forward to wrap even complicated headers, and also apply the needed transformation (e.g. the whole function pointer loading) as part of the Clang build ;)