:right-sidebar: True GLContext =================================================================== .. currentmodule:: gi.repository.Gdk .. class:: GLContext(**properties: ~typing.Any) :no-contents-entry: Superclasses: :class:`~gi.repository.Gdk.DrawContext`, :class:`~gi.repository.GObject.Object` ``GdkGLContext`` is an object representing a platform-specific OpenGL draw context. ``GdkGLContext``\s are created for a surface using :obj:`~gi.repository.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 :obj:`~gi.repository.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 :const:`None` 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 :obj:`~gi.repository.Gdk.GLContext.make_current` or :obj:`~gi.repository.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 :obj:`~gi.repository.Gdk.Surface.create_gl_context` by calling :obj:`~gi.repository.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: .. code-block:: c :dedent: 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 :obj:`~gi.repository.Gdk.GLContext.get_current`\; you can also unset any ``GdkGLContext`` that is currently set by calling :obj:`~gi.repository.Gdk.GLContext.clear_current`\. Methods ------- .. rst-class:: interim-class .. class:: GLContext :no-index: .. classmethod:: clear_current() -> None Clears the current ``GdkGLContext``\. Any OpenGL call after this function returns will be ignored until :obj:`~gi.repository.Gdk.GLContext.make_current` is called. .. method:: get_allowed_apis() -> ~gi.repository.Gdk.GLAPI Gets the allowed APIs set via :func:`~gi.repository.Gdk.GLContext.set_allowed_apis`. .. versionadded:: 4.6 .. method:: get_api() -> ~gi.repository.Gdk.GLAPI Gets the API currently in use. If the renderer has not been realized yet, 0 is returned. .. versionadded:: 4.6 .. classmethod:: get_current() -> ~gi.repository.Gdk.GLContext | None Retrieves the current ``GdkGLContext``\. .. method:: get_debug_enabled() -> bool Retrieves whether the context is doing extra validations and runtime checking. See :obj:`~gi.repository.Gdk.GLContext.set_debug_enabled`\. .. method:: get_display() -> ~gi.repository.Gdk.Display | None Retrieves the display the ``context`` is created for .. method:: get_forward_compatible() -> bool Retrieves whether the context is forward-compatible. See :obj:`~gi.repository.Gdk.GLContext.set_forward_compatible`\. .. method:: get_required_version() -> ~typing.Tuple[int | None, int | None] 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 :obj:`~gi.repository.Gdk.GLContext.get_version` for the real version in use. See :obj:`~gi.repository.Gdk.GLContext.set_required_version`\. .. method:: get_shared_context() -> ~gi.repository.Gdk.GLContext | None Used to retrieves the ``GdkGLContext`` that this ``context`` share data with. As many contexts can share data now and no single shared context exists anymore, this function has been deprecated and now always returns :const:`None`. .. deprecated:: 4.4 Use :obj:`~gi.repository.Gdk.GLContext.is_shared` to check if contexts can be shared. .. method:: get_surface() -> ~gi.repository.Gdk.Surface | None Retrieves the surface used by the ``context``\. .. method:: get_use_es() -> bool Checks whether the ``context`` is using an OpenGL or OpenGL ES profile. .. method:: get_version() -> ~typing.Tuple[int, int] Retrieves the OpenGL version of the ``context``\. The ``context`` must be realized prior to calling this function. .. method:: is_legacy() -> bool Whether the ``GdkGLContext`` is in legacy mode or not. The ``GdkGLContext`` must be realized before calling this function. When realizing a GL context, GDK will try to use the OpenGL 3.2 core profile; this profile removes all the OpenGL API that was deprecated prior to the 3.2 version of the specification. If the realization is successful, this function will return :const:`False`. If the underlying OpenGL implementation does not support core profiles, GDK will fall back to a pre-3.2 compatibility profile, and this function will return :const:`True`. You can use the value returned by this function to decide which kind of OpenGL API to use, or whether to do extension discovery, or what kind of shader programs to load. .. method:: is_shared(other: ~gi.repository.Gdk.GLContext) -> bool Checks if the two GL contexts can share resources. When they can, the texture IDs from ``other`` can be used in ``self``\. This is particularly useful when passing ``GdkGLTexture`` objects between different contexts. Contexts created for the same display with the same properties will always be compatible, even if they are created for different surfaces. For other contexts it depends on the GL backend. Both contexts must be realized for this check to succeed. If either one is not, this function will return :const:`False`. .. versionadded:: 4.4 :param other: the ``GdkGLContext`` that should be compatible with ``self`` .. method:: make_current() -> None Makes the ``context`` the current one. .. method:: realize() -> bool Realizes the given ``GdkGLContext``\. It is safe to call this function on a realized ``GdkGLContext``\. .. method:: set_allowed_apis(apis: ~gi.repository.Gdk.GLAPI) -> None Sets the allowed APIs. When :func:`~gi.repository.Gdk.GLContext.realize` is called, only the allowed APIs will be tried. If you set this to 0, realizing will always fail. If you set it on a realized context, the property will not have any effect. It is only relevant during :func:`~gi.repository.Gdk.GLContext.realize`. By default, all APIs are allowed. .. versionadded:: 4.6 :param apis: the allowed APIs .. method:: set_debug_enabled(enabled: bool) -> None Sets whether the ``GdkGLContext`` should perform extra validations and runtime checking. This is useful during development, but has additional overhead. The ``GdkGLContext`` must not be realized or made current prior to calling this function. :param enabled: whether to enable debugging in the context .. method:: set_forward_compatible(compatible: bool) -> None Sets whether the ``GdkGLContext`` should be forward-compatible. Forward-compatible contexts must not support OpenGL functionality that has been marked as deprecated in the requested version; non-forward compatible contexts, on the other hand, must support both deprecated and non deprecated functionality. The ``GdkGLContext`` must not be realized or made current prior to calling this function. :param compatible: whether the context should be forward-compatible .. method:: set_required_version(major: int, minor: int) -> None Sets the major and minor version of OpenGL to request. Setting ``major`` and ``minor`` to zero will use the default values. Setting ``major`` and ``minor`` lower than the minimum versions required by GTK will result in the context choosing the minimum version. The ``context`` must not be realized or made current prior to calling this function. :param major: the major version to request :param minor: the minor version to request .. method:: set_use_es(use_es: int) -> None Requests that GDK create an OpenGL ES context instead of an OpenGL one. Not all platforms support OpenGL ES. The ``context`` must not have been realized. By default, GDK will attempt to automatically detect whether the underlying GL implementation is OpenGL or OpenGL ES once the ``context`` is realized. You should check the return value of :obj:`~gi.repository.Gdk.GLContext.get_use_es` after calling :obj:`~gi.repository.Gdk.GLContext.realize` to decide whether to use the OpenGL or OpenGL ES API, extensions, or shaders. :param use_es: whether the context should use OpenGL ES instead of OpenGL, or -1 to allow auto-detection Properties ---------- .. rst-class:: interim-class .. class:: GLContext :no-index: .. attribute:: props.allowed_apis :type: ~gi.repository.Gdk.GLAPI The type of the None singleton. .. versionadded:: 4.6 .. attribute:: props.api :type: ~gi.repository.Gdk.GLAPI The type of the None singleton. .. versionadded:: 4.6 .. attribute:: props.shared_context :type: ~gi.repository.Gdk.GLContext The type of the None singleton. .. deprecated:: 4.4 Use :obj:`~gi.repository.Gdk.GLContext.is_shared` to check if contexts can be shared.