Gdk.GLContext
Description: Reference for Gdk.GLContext

### Class

# GdkGLContext

#### Description [src]

    abstract class Gdk.GLContext : Gdk.DrawContext
    {
      /* No available fields */
    }

`GdkGLContext` is an object representing a platform-specific OpenGL draw context.

`GdkGLContext`s are created for a surface using `gdk_surface_create_gl_context()`, and the context will match 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 `gdk_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 `gdk_gl_context_make_current()` or `gdk_gl_context_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 `gdk_surface_create_gl_context()` by calling `gdk_gl_context_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:

    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 `gdk_gl_context_get_current()`; you can also unset any `GdkGLContext` that is currently set by calling `gdk_gl_context_clear_current()`.

#### Ancestors

- GdkDrawContext
- GObject

#### Functions

###### gdk_gl_context_clear_current

Clears the current `GdkGLContext`.

###### gdk_gl_context_get_current

Retrieves the current `GdkGLContext`.

#### Instance methods

###### gdk_gl_context_get_allowed_apis

Gets the allowed APIs set via gdk_gl_context_set_allowed_apis().

since: 4.6

###### gdk_gl_context_get_api

Gets the API currently in use.

since: 4.6

###### gdk_gl_context_get_debug_enabled

Retrieves whether the context is doing extra validations and runtime checking.

###### gdk_gl_context_get_display

Retrieves the display the `context` is created for.

###### gdk_gl_context_get_forward_compatible

Retrieves whether the context is forward-compatible.

###### gdk_gl_context_get_required_version

Retrieves required OpenGL version set as a requirement for the `context` realization. It will not change even if a greater OpenGL version is supported and used after the `context` is realized. See `gdk_gl_context_get_version()` for the real version in use.

###### gdk_gl_context_get_shared_context

Used to retrieves the `GdkGLContext` that this `context` share data with.

deprecated: 4.4

###### gdk_gl_context_get_surface

Retrieves the surface used by the `context`.

###### gdk_gl_context_get_use_es

Checks whether the `context` is using an OpenGL or OpenGL ES profile.

###### gdk_gl_context_get_version

Retrieves the OpenGL version of the `context`.

###### gdk_gl_context_is_legacy

Whether the `GdkGLContext` is in legacy mode or not.

###### gdk_gl_context_is_shared

Checks if the two GL contexts can share resources.

since: 4.4

###### gdk_gl_context_make_current

Makes the `context` the current one.

###### gdk_gl_context_realize

Realizes the given `GdkGLContext`.

###### gdk_gl_context_set_allowed_apis

Sets the allowed APIs. When `gdk_gl_context_realize()` is called, only the allowed APIs will be tried. If you set this to 0, realizing will always fail.

since: 4.6

###### gdk_gl_context_set_debug_enabled

Sets whether the `GdkGLContext` should perform extra validations and runtime checking.

###### gdk_gl_context_set_forward_compatible

Sets whether the `GdkGLContext` should be forward-compatible.

###### gdk_gl_context_set_required_version

Sets the major and minor version of OpenGL to request.

###### gdk_gl_context_set_use_es

Requests that GDK create an OpenGL ES context instead of an OpenGL one.

##### Methods inherited from GdkDrawContext (6)

###### gdk_draw_context_begin_frame

Indicates that you are beginning the process of redrawing `region` on the `context`‘s surface.

###### gdk_draw_context_end_frame

Ends a drawing operation started with gdk_draw_context_begin_frame().

###### gdk_draw_context_get_display

Retrieves the `GdkDisplay` the `context` is created for.

###### gdk_draw_context_get_frame_region

Retrieves the region that is currently being repainted.

###### gdk_draw_context_get_surface

Retrieves the surface that `context` is bound to.

###### gdk_draw_context_is_in_frame

Returns `TRUE` if `context` is in the process of drawing to its surface.

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

#### Properties

###### Gdk.GLContext:allowed-apis

The allowed APIs.

since: 4.6

###### Gdk.GLContext:api

The API currently in use.

since: 4.6

###### Gdk.GLContext:shared-context

Always `NULL`.

deprecated: 4.4

##### Properties inherited from GdkDrawContext (2)

###### Gdk.DrawContext:display

The `GdkDisplay` used to create the `GdkDrawContext`.

###### Gdk.DrawContext:surface

The `GdkSurface` the context is bound to.

#### Signals

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.