Struct gdk4::GLContext

#[repr(transparent)]
pub struct GLContext { /* private fields */ }

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

GLContexts are created for a surface using SurfaceExt::create_gl_context(), and the context will match the characteristics of the surface.

A GLContext 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 [draw_from_gl()][crate::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 GLContext is platform-specific and context creation can fail, returning None context.

A GLContext 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 GLContext instance you need a Surface, which you typically get during the realize call of a widget.

A GLContext is not realized until either GLContextExt::make_current() or GLContextExt::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 SurfaceExt::create_gl_context() by calling GLContextExt::realize(). If the realization fails you have the option to change the settings of the GLContext and try again.

Using a GdkGLContext

You will need to make the GLContext 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:

⚠️ The following code is in c ⚠️

gdk_gl_context_make_current (context);

You can now perform your drawing using OpenGL commands.

You can check which GLContext is the current one by using current(); you can also unset any GLContext that is currently set by calling clear_current().

This is an Abstract Base Class, you cannot instantiate it.

Implements

GLContextExt, DrawContextExt, DrawContextExtManual

Implementations

impl GLContext

pub const NONE: Option<&'static GLContext> = None

pub fn clear_current()

Clears the current GLContext.

Any OpenGL call after this function returns will be ignored until GLContextExt::make_current() is called.

pub fn current() -> Option<GLContext>

Retrieves the current GLContext.

Returns

the current GLContext

Trait Implementations

impl Clone for GLContext

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GLContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for GLContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for GLContext

fn hash<H>(&self, state: &mut H)where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for GLContext

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for GLContext

type Parent = DrawContext

impl<OT: ObjectType> PartialEq<OT> for GLContext

fn eq(&self, other: &OT) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for GLContext

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for GLContext

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for GLContext

impl IsA<DrawContext> for GLContext