public abstract class GLContext : DrawContext
`GdkGLContext` is an object representing a platform-specific OpenGL draw context.
`GdkGLContext`s are created for a surface using [method@Gdk.Surface.create_gl_context], and the context will match the the characteristics of the surface.
A `GdkGLContext` is not tied to any particular normal framebuffer. For instance, it cannot draw to the surface back buffer. The GDK repaint system is in full control of the painting to that. Instead, you can create render buffers or textures and use [func@cairo_draw_from_gl] in the draw function of your widget to draw them. Then GDK will handle the integration of your rendering with that of other widgets.
Support for `GdkGLContext` is platform-specific and context creation can fail, returning null context.
A `GdkGLContext` has to be made "current" in order to start using it, otherwise any OpenGL call will be ignored.
Creating a new OpenGL context
In order to create a new `GdkGLContext` instance you need a `GdkSurface`, which you typically get during the realize call of a widget.
A `GdkGLContext` is not realized until either [method@Gdk.GLContext.make_current] or [method@Gdk.GLContext.realize] is called. It is possible to specify details of the GL context like the OpenGL version to be used, or whether the GL context should have extra state validation enabled after calling [method@Gdk.Surface.create_gl_context] by calling [method@Gdk.GLContext.realize]. If the realization fails you have the option to change the settings of the `GdkGLContext` and try again.
Using a GdkGLContext
You will need to make the `GdkGLContext` the current context before issuing OpenGL calls; the system sends OpenGL commands to whichever context is current. It is possible to have multiple contexts, so you always need to ensure that the one which you want to draw with is the current one before issuing commands:
```c gdk_gl_context_make_current (context); ```
You can now perform your drawing using OpenGL commands.
You can check which `GdkGLContext` is the current one by using [func@Gdk.GLContext.get_current]; you can also unset any `GdkGLContext` that is currently set by calling [func@Gdk.GLContext.clear_current].