DerelictGL3.reload with specified path question.

[Mike Parker via Digitalmars-d-learn]

On Thursday, 18 August 2016 at 03:54:24 UTC, WhatMeWorry wrote:
>
> When I saw the .dll in OpenGL.dll, I immediately thought: just 
> Windows. But does this hold true for the linux shared opengl 
> libraries as well? Is this why DerelictGL3.reload() does not 
> take a path argument.  But then why 
> doesDerelictGL3.load(lib)take an argument?

The load method is what actually loads the shared library. On 
Windows, that's OpenGL32.dll. All of the platform-specific 
library names are configured at the top of gl3.d [1]. In addition 
to loading the library, it also loads the functions up to OpenGL 
1.1, but no higher. This is because the availability of other 
functions are dependent on the version of the active OpenGL 
context.

The reload method *does not* load the shared library, nor does it 
load the 1.1 functions. It loads the functions from OpenGL 
versions 1.2 and higher in addition to all available extensions 
(well, those for which support has been added to DerelictGL3). 
It's named reload because it should be called every time you 
switch contexts to make sure the functions are pointed in the 
right place. This is an artifact of the way OpenGL is handled on 
Windows. In practice, it's really only a problem there when 
switching between contexts that have different properties, but it 
simplifies the binding implementation and provides a uniform 
interface across platforms.

I'm current working on a new version of the library that will 
allow you to specify which OpenGL versions and extensions you 
want to load and will also let you wrap everything in a struct so 
that you can have one instance for each context, but the 
distinction between load and reload will still exist.

[1] 
https://github.com/DerelictOrg/DerelictGL3/blob/master/source/derelict/opengl3/gl3.d#L47