class Gtk::GLArea

Overview

Gtk::GLArea is a widget that allows drawing with OpenGL.

An example Gtk::GLArea

Gtk::GLArea sets up its own Gdk::GLContext, and creates a custom GL framebuffer that the widget will do GL rendering onto. It also ensures that this framebuffer is the default GL rendering target when rendering.

In order to draw, you have to connect to the Gtk::GLArea::#render signal, or subclass Gtk::GLArea and override the Gtk::GLAreaClass.render virtual function.

The Gtk::GLArea widget ensures that the Gdk::GLContext is associated with the widget's drawing area, and it is kept updated when the size and position of the drawing area changes.

Drawing with Gtk::GLArea

The simplest way to draw using OpenGL commands in a Gtk::GLArea is to create a widget instance and connect to the Gtk::GLArea::#render signal:

The render() function will be called when the Gtk::GLArea is ready for you to draw its content:

WARNING ⚠️ The following code is in c ⚠️

static gboolean
render (Gtk::GLArea *area, Gdk::GLContext *context)
{
  // inside this function it's safe to use GL; the given
  // Gdk::GLContext has been made current to the drawable
  // surface used by the `Gtk::GLArea` and the viewport has
  // already been set to be the size of the allocation

  // we can start by clearing the buffer
  glClearColor (0, 0, 0, 0);
  glClear (GL_COLOR_BUFFER_BIT);

  // draw your object
  // draw_an_object ();

  // we completed our drawing; the draw commands will be
  // flushed at the end of the signal emission chain, and
  // the buffers will be drawn on the window
  return TRUE;
}

void setup_glarea (void)
{
  // create a Gtk::GLArea instance
  Gtk::Widget *gl_area = gtk_gl_area_new ();

  // connect to the "render" signal
  g_signal_connect (gl_area, "render", G_CALLBACK (render), NULL);
}

If you need to initialize OpenGL state, e.g. buffer objects or shaders, you should use the Gtk::Widget::#realize signal; you can use the Gtk::Widget::#unrealize signal to clean up. Since the Gdk::GLContext creation and initialization may fail, you will need to check for errors, using Gtk::GLArea#error.

An example of how to safely initialize the GL state is:

WARNING ⚠️ The following code is in c ⚠️

static void
on_realize (Gtk::GLarea *area)
{
  // We need to make the context current if we want to
  // call GL API
  gtk_gl_area_make_current (area);

  // If there were errors during the initialization or
  // when trying to make the context current, this
  // function will return a GError for you to catch
  if (gtk_gl_area_get_error (area) != NULL)
    return;

  // You can also use gtk_gl_area_set_error() in order
  // to show eventual initialization errors on the
  // Gtk::GLArea widget itself
  GError *internal_error = NULL;
  init_buffer_objects (&error);
  if (error != NULL)
    {
      gtk_gl_area_set_error (area, error);
      g_error_free (error);
      return;
    }

  init_shaders (&error);
  if (error != NULL)
    {
      gtk_gl_area_set_error (area, error);
      g_error_free (error);
      return;
    }
}

If you need to change the options for creating the Gdk::GLContext you should use the [signal@Gtk.GLArea::create-context] signal.

Included Modules

Defined in:

lib/gi-crystal/src/auto/gtk-4.0/gl_area.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module Gtk::ConstraintTarget

to_unsafe to_unsafe

Constructor methods inherited from module Gtk::ConstraintTarget

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::ConstraintTarget

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from module Gtk::Buildable

buildable_id : String | Nil buildable_id, to_unsafe to_unsafe

Constructor methods inherited from module Gtk::Buildable

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::Buildable

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from module Gtk::Accessible

accessible_role : Gtk::AccessibleRole accessible_role, accessible_role=(value : Gtk::AccessibleRole) : Gtk::AccessibleRole accessible_role=, reset_property(property : Gtk::AccessibleProperty) : Nil reset_property, reset_relation(relation : Gtk::AccessibleRelation) : Nil reset_relation, reset_state(state : Gtk::AccessibleState) : Nil reset_state, to_unsafe to_unsafe, update_property(properties : Enumerable(Gtk::AccessibleProperty), values : Enumerable(_)) : Nil update_property, update_relation(relations : Enumerable(Gtk::AccessibleRelation), values : Enumerable(_)) : Nil update_relation, update_state(states : Enumerable(Gtk::AccessibleState), values : Enumerable(_)) : Nil update_state

Constructor methods inherited from module Gtk::Accessible

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::Accessible

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from class Gtk::Widget

==(other : self) ==, action_set_enabled(action_name : String, enabled : Bool) : Nil action_set_enabled, activate : Bool activate, activate_action(name : String, args : _ | Nil) : Bool activate_action, activate_default : Nil activate_default, add_controller(controller : Gtk::EventController) : Nil add_controller, add_css_class(css_class : String) : Nil add_css_class, add_mnemonic_label(label : Gtk::Widget) : Nil add_mnemonic_label, add_tick_callback(callback : Gtk::TickCallback) : UInt32 add_tick_callback, allocate(width : Int32, height : Int32, baseline : Int32, transform : Gsk::Transform | Nil) : Nil allocate, allocated_baseline : Int32 allocated_baseline, allocated_height : Int32 allocated_height, allocated_width : Int32 allocated_width, allocation : Gdk::Rectangle allocation, ancestor(widget_type : UInt64) : Gtk::Widget | Nil ancestor, can_focus : Bool can_focus, can_focus=(can_focus : Bool) : Nil can_focus=, can_focus? : Bool can_focus?, can_target : Bool can_target, can_target=(can_target : Bool) : Nil can_target=, can_target? : Bool can_target?, child_focus(direction : Gtk::DirectionType) : Bool child_focus, child_visible : Bool child_visible, child_visible=(child_visible : Bool) : Nil child_visible=, children : Iterator(Widget) children, clipboard : Gdk::Clipboard clipboard, compute_bounds(target : Gtk::Widget) : Graphene::Rect compute_bounds, compute_expand(orientation : Gtk::Orientation) : Bool compute_expand, compute_point(target : Gtk::Widget, point : Graphene::Point) : Graphene::Point compute_point, compute_transform(target : Gtk::Widget) : Graphene::Matrix compute_transform, contains(x : Float64, y : Float64) : Bool contains, create_pango_context : Pango::Context create_pango_context, create_pango_layout(text : String | Nil) : Pango::Layout create_pango_layout, css_classes : Enumerable(String) css_classes, css_classes=(classes : Enumerable(String)) : Nil css_classes=, css_name : String css_name, css_name=(value : String) : String css_name=, cursor : Gdk::Cursor | Nil cursor, cursor=(cursor : Gdk::Cursor | Nil) : Nil cursor=, cursor_from_name=(name : String | Nil) : Nil cursor_from_name=, destroy_signal destroy_signal, direction : Gtk::TextDirection direction, direction=(dir : Gtk::TextDirection) : Nil direction=, direction_changed_signal direction_changed_signal, display : Gdk::Display display, drag_check_threshold(start_x : Int32, start_y : Int32, current_x : Int32, current_y : Int32) : Bool drag_check_threshold, error_bell : Nil error_bell, first_child : Gtk::Widget | Nil first_child, focus_child : Gtk::Widget | Nil focus_child, focus_child=(child : Gtk::Widget | Nil) : Nil focus_child=, focus_on_click : Bool focus_on_click, focus_on_click=(focus_on_click : Bool) : Nil focus_on_click=, focus_on_click? : Bool focus_on_click?, focusable : Bool focusable, focusable=(focusable : Bool) : Nil focusable=, focusable? : Bool focusable?, font_map : Pango::FontMap | Nil font_map, font_map=(font_map : Pango::FontMap | Nil) : Nil font_map=, font_options : Cairo::FontOptions | Nil font_options, font_options=(options : Cairo::FontOptions | Nil) : Nil font_options=, frame_clock : Gdk::FrameClock | Nil frame_clock, grab_focus : Bool grab_focus, halign : Gtk::Align halign, halign=(align : Gtk::Align) : Nil halign=, has_css_class(css_class : String) : Bool has_css_class, has_default : Bool has_default, has_default? : Bool has_default?, has_focus : Bool has_focus, has_focus? : Bool has_focus?, has_tooltip : Bool has_tooltip, has_tooltip=(has_tooltip : Bool) : Nil has_tooltip=, has_tooltip? : Bool has_tooltip?, has_visible_focus : Bool has_visible_focus, hash(hasher) hash, height : Int32 height, height_request : Int32 height_request, height_request=(value : Int32) : Int32 height_request=, hexpand : Bool hexpand, hexpand=(expand : Bool) : Nil hexpand=, hexpand? : Bool hexpand?, hexpand_set : Bool hexpand_set, hexpand_set=(set : Bool) : Nil hexpand_set=, hexpand_set? : Bool hexpand_set?, hide : Nil hide, hide_signal hide_signal, in_destruction : Bool in_destruction, init_template : Nil init_template, insert_action_group(name : String, group : Gio::ActionGroup | Nil) : Nil insert_action_group, insert_after(parent : Gtk::Widget, previous_sibling : Gtk::Widget | Nil) : Nil insert_after, insert_before(parent : Gtk::Widget, next_sibling : Gtk::Widget | Nil) : Nil insert_before, is_ancestor(ancestor : Gtk::Widget) : Bool is_ancestor, is_drawable : Bool is_drawable, is_focus : Bool is_focus, is_sensitive : Bool is_sensitive, is_visible : Bool is_visible, keynav_failed(direction : Gtk::DirectionType) : Bool keynav_failed, keynav_failed_signal keynav_failed_signal, last_child : Gtk::Widget | Nil last_child, layout_manager : Gtk::LayoutManager | Nil layout_manager, layout_manager=(layout_manager : Gtk::LayoutManager | Nil) : Nil layout_manager=, list_mnemonic_labels : GLib::List list_mnemonic_labels, map : Nil map, map_signal map_signal, mapped : Bool mapped, margin_bottom : Int32 margin_bottom, margin_bottom=(margin : Int32) : Nil margin_bottom=, margin_end : Int32 margin_end, margin_end=(margin : Int32) : Nil margin_end=, margin_start : Int32 margin_start, margin_start=(margin : Int32) : Nil margin_start=, margin_top : Int32 margin_top, margin_top=(margin : Int32) : Nil margin_top=, measure(orientation : Gtk::Orientation, for_size : Int32) : Nil measure, mnemonic_activate(group_cycling : Bool) : Bool mnemonic_activate, mnemonic_activate_signal mnemonic_activate_signal, move_focus_signal move_focus_signal, name : String name, name=(name : String) : Nil name=, native : Gtk::Native | Nil native, next_sibling : Gtk::Widget | Nil next_sibling, observe_children : Gio::ListModel observe_children, observe_controllers : Gio::ListModel observe_controllers, opacity : Float64 opacity, opacity=(opacity : Float64) : Nil opacity=, overflow : Gtk::Overflow overflow, overflow=(overflow : Gtk::Overflow) : Nil overflow=, pango_context : Pango::Context pango_context, parent : Gtk::Widget | Nil parent, parent=(parent : Gtk::Widget) : Nil parent=, pick(x : Float64, y : Float64, flags : Gtk::PickFlags) : Gtk::Widget | Nil pick, preferred_size : Gtk::Requisition preferred_size, prev_sibling : Gtk::Widget | Nil prev_sibling, primary_clipboard : Gdk::Clipboard primary_clipboard, query_tooltip_signal query_tooltip_signal, queue_allocate : Nil queue_allocate, queue_draw : Nil queue_draw, queue_resize : Nil queue_resize, realize : Nil realize, realize_signal realize_signal, realized : Bool realized, receives_default : Bool receives_default, receives_default=(receives_default : Bool) : Nil receives_default=, receives_default? : Bool receives_default?, remove_controller(controller : Gtk::EventController) : Nil remove_controller, remove_css_class(css_class : String) : Nil remove_css_class, remove_mnemonic_label(label : Gtk::Widget) : Nil remove_mnemonic_label, remove_tick_callback(id : UInt32) : Nil remove_tick_callback, request_mode : Gtk::SizeRequestMode request_mode, root : Gtk::Root | Nil root, scale_factor : Int32 scale_factor, sensitive : Bool sensitive, sensitive=(sensitive : Bool) : Nil sensitive=, sensitive? : Bool sensitive?, set_size_request(width : Int32, height : Int32) : Nil set_size_request, set_state_flags(flags : Gtk::StateFlags, clear : Bool) : Nil set_state_flags, settings : Gtk::Settings settings, should_layout : Bool should_layout, show : Nil show, show_signal show_signal, size(orientation : Gtk::Orientation) : Int32 size, size_allocate(allocation : Gdk::Rectangle, baseline : Int32) : Nil size_allocate, size_request : Nil size_request, snapshot_child(child : Gtk::Widget, snapshot : Gtk::Snapshot) : Nil snapshot_child, state_flags : Gtk::StateFlags state_flags, state_flags_changed_signal state_flags_changed_signal, style_context : Gtk::StyleContext style_context, template_child(widget_type : UInt64, name : String) : GObject::Object
template_child(name : String) : GObject::Object
template_child
, tooltip_markup : String | Nil tooltip_markup, tooltip_markup=(value : String) : String
tooltip_markup=(markup : String | Nil) : Nil
tooltip_markup=
, tooltip_text : String | Nil tooltip_text, tooltip_text=(value : String) : String
tooltip_text=(text : String | Nil) : Nil
tooltip_text=
, translate_coordinates(dest_widget : Gtk::Widget, src_x : Float64, src_y : Float64) : Bool translate_coordinates, trigger_tooltip_query : Nil trigger_tooltip_query, unmap : Nil unmap, unmap_signal unmap_signal, unparent : Nil unparent, unrealize : Nil unrealize, unrealize_signal unrealize_signal, unset_state_flags(flags : Gtk::StateFlags) : Nil unset_state_flags, valign : Gtk::Align valign, valign=(align : Gtk::Align) : Nil valign=, vexpand : Bool vexpand, vexpand=(expand : Bool) : Nil vexpand=, vexpand? : Bool vexpand?, vexpand_set : Bool vexpand_set, vexpand_set=(set : Bool) : Nil vexpand_set=, vexpand_set? : Bool vexpand_set?, visible : Bool visible, visible=(visible : Bool) : Nil visible=, visible? : Bool visible?, width : Int32 width, width_request : Int32 width_request, width_request=(value : Int32) : Int32 width_request=

Constructor methods inherited from class Gtk::Widget

new
new(*, accessible_role : Gtk::AccessibleRole | Nil = nil, can_focus : Bool | Nil = nil, can_target : Bool | Nil = nil, css_classes : Enumerable(String) | Nil = nil, css_name : String | Nil = nil, cursor : Gdk::Cursor | Nil = nil, focus_on_click : Bool | Nil = nil, focusable : Bool | Nil = nil, halign : Gtk::Align | Nil = nil, has_default : Bool | Nil = nil, has_focus : Bool | Nil = nil, has_tooltip : Bool | Nil = nil, height_request : Int32 | Nil = nil, hexpand : Bool | Nil = nil, hexpand_set : Bool | Nil = nil, layout_manager : Gtk::LayoutManager | Nil = nil, margin_bottom : Int32 | Nil = nil, margin_end : Int32 | Nil = nil, margin_start : Int32 | Nil = nil, margin_top : Int32 | Nil = nil, name : String | Nil = nil, opacity : Float64 | Nil = nil, overflow : Gtk::Overflow | Nil = nil, parent : Gtk::Widget | Nil = nil, receives_default : Bool | Nil = nil, root : Gtk::Root | Nil = nil, scale_factor : Int32 | Nil = nil, sensitive : Bool | Nil = nil, tooltip_markup : String | Nil = nil, tooltip_text : String | Nil = nil, valign : Gtk::Align | Nil = nil, vexpand : Bool | Nil = nil, vexpand_set : Bool | Nil = nil, visible : Bool | Nil = nil, width_request : Int32 | Nil = nil)
new

Class methods inherited from class Gtk::Widget

default_direction : Gtk::TextDirection default_direction, default_direction=(dir : Gtk::TextDirection) : Nil default_direction=, g_type : UInt64 g_type

Instance methods inherited from module Gtk::ConstraintTarget

to_unsafe to_unsafe

Constructor methods inherited from module Gtk::ConstraintTarget

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::ConstraintTarget

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from module Gtk::Buildable

buildable_id : String | Nil buildable_id, to_unsafe to_unsafe

Constructor methods inherited from module Gtk::Buildable

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::Buildable

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from module Gtk::Accessible

accessible_role : Gtk::AccessibleRole accessible_role, accessible_role=(value : Gtk::AccessibleRole) : Gtk::AccessibleRole accessible_role=, reset_property(property : Gtk::AccessibleProperty) : Nil reset_property, reset_relation(relation : Gtk::AccessibleRelation) : Nil reset_relation, reset_state(state : Gtk::AccessibleState) : Nil reset_state, to_unsafe to_unsafe, update_property(properties : Enumerable(Gtk::AccessibleProperty), values : Enumerable(_)) : Nil update_property, update_relation(relations : Enumerable(Gtk::AccessibleRelation), values : Enumerable(_)) : Nil update_relation, update_state(states : Enumerable(Gtk::AccessibleState), values : Enumerable(_)) : Nil update_state

Constructor methods inherited from module Gtk::Accessible

cast(obj : GObject::Object) : self cast

Class methods inherited from module Gtk::Accessible

cast?(obj : GObject::Object) : self | Nil cast?, g_type : UInt64 g_type

Instance methods inherited from class GObject::InitiallyUnowned

==(other : self) ==, hash(hasher) hash

Constructor methods inherited from class GObject::InitiallyUnowned

new new

Class methods inherited from class GObject::InitiallyUnowned

g_type : UInt64 g_type

Instance methods inherited from class GObject::Object

==(other : self) ==, bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void) | Nil data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, hash(hasher) hash, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void) | Nil qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void) | Nil) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void) | Nil steal_data, steal_qdata(quark : UInt32) : Pointer(Void) | Nil steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new
new
, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

cast?(obj : GObject::Object) : self | Nil cast?, compat_control(what : UInt64, data : Pointer(Void) | Nil) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new : self #

Creates a new Gtk::GLArea widget.


[View source]
def self.new(*, accessible_role : Gtk::AccessibleRole | Nil = nil, auto_render : Bool | Nil = nil, can_focus : Bool | Nil = nil, can_target : Bool | Nil = nil, context : Gdk::GLContext | Nil = nil, css_classes : Enumerable(String) | Nil = nil, css_name : String | Nil = nil, cursor : Gdk::Cursor | Nil = nil, focus_on_click : Bool | Nil = nil, focusable : Bool | Nil = nil, halign : Gtk::Align | Nil = nil, has_default : Bool | Nil = nil, has_depth_buffer : Bool | Nil = nil, has_focus : Bool | Nil = nil, has_stencil_buffer : Bool | Nil = nil, has_tooltip : Bool | Nil = nil, height_request : Int32 | Nil = nil, hexpand : Bool | Nil = nil, hexpand_set : Bool | Nil = nil, layout_manager : Gtk::LayoutManager | Nil = nil, margin_bottom : Int32 | Nil = nil, margin_end : Int32 | Nil = nil, margin_start : Int32 | Nil = nil, margin_top : Int32 | Nil = nil, name : String | Nil = nil, opacity : Float64 | Nil = nil, overflow : Gtk::Overflow | Nil = nil, parent : Gtk::Widget | Nil = nil, receives_default : Bool | Nil = nil, root : Gtk::Root | Nil = nil, scale_factor : Int32 | Nil = nil, sensitive : Bool | Nil = nil, tooltip_markup : String | Nil = nil, tooltip_text : String | Nil = nil, use_es : Bool | Nil = nil, valign : Gtk::Align | Nil = nil, vexpand : Bool | Nil = nil, vexpand_set : Bool | Nil = nil, visible : Bool | Nil = nil, width_request : Int32 | Nil = nil) #

[View source]

Class Method Detail

def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.


[View source]

Instance Method Detail

def ==(other : self) #
Description copied from class Reference

Returns true if this reference is the same as other. Invokes same?.


def attach_buffers : Nil #

Binds buffers to the framebuffer.

Ensures that the area framebuffer object is made the current draw and read target, and that all the required buffers for the area are created and bound to the framebuffer.

This function is automatically called before emitting the Gtk::GLArea::#render signal, and doesn't normally need to be called by application code.


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def auto_render : Bool #

Returns whether the area is in auto render mode or not.


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def auto_render=(auto_render : Bool) : Nil #

Sets whether the Gtk::GLArea is in auto render mode.

If auto_render is true the Gtk::GLArea::#render signal will be emitted every time the widget draws. This is the default and is useful if drawing the widget is faster.

If auto_render is false the data from previous rendering is kept around and will be used for drawing the widget the next time, unless the window is resized. In order to force a rendering Gtk::GLArea#queue_render must be called. This mode is useful when the scene changes seldom, but takes a long time to redraw.


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def auto_render? : Bool #

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def context : Gdk::GLContext | Nil #

Retrieves the Gdk::GLContext used by area.


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def create_context_signal #

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def error : GLib::Error | Nil #

Gets the current error set on the area.


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def error=(error : GLib::Error | Nil) : Nil #

Sets an error on the area which will be shown instead of the GL rendering.

This is useful in the [signal@Gtk.GLArea::create-context] signal if GL context creation fails.


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def has_depth_buffer : Bool #

Returns whether the area has a depth buffer.


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def has_depth_buffer=(has_depth_buffer : Bool) : Nil #

Sets whether the Gtk::GLArea should use a depth buffer.

If has_depth_buffer is true the widget will allocate and enable a depth buffer for the target framebuffer. Otherwise there will be none.


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def has_depth_buffer? : Bool #

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def has_stencil_buffer : Bool #

Returns whether the area has a stencil buffer.


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def has_stencil_buffer=(has_stencil_buffer : Bool) : Nil #

Sets whether the Gtk::GLArea should use a stencil buffer.

If has_stencil_buffer is true the widget will allocate and enable a stencil buffer for the target framebuffer. Otherwise there will be none.


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def has_stencil_buffer? : Bool #

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def hash(hasher) #
Description copied from class Reference

See Object#hash(hasher)


def make_current : Nil #

Ensures that the Gdk::GLContext used by area is associated with the Gtk::GLArea.

This function is automatically called before emitting the Gtk::GLArea::#render signal, and doesn't normally need to be called by application code.


[View source]
def queue_render : Nil #

Marks the currently rendered data (if any) as invalid, and queues a redraw of the widget.

This ensures that the Gtk::GLArea::#render signal is emitted during the draw.

This is only needed when Gtk::GLArea#auto_render= has been called with a false value. The default behaviour is to emit Gtk::GLArea::#render on each draw.


[View source]
def render_signal #

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def required_version(major : Int32, minor : Int32) : Nil #

Retrieves the required version of OpenGL.

See Gtk::GLArea#required_version=.


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def resize_signal #

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def set_required_version(major : Int32, minor : Int32) : Nil #

Sets the required version of OpenGL to be used when creating the context for the widget.

This function must be called before the area has been realized.


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def use_es : Bool #

Returns whether the Gtk::GLArea should use OpenGL ES.

See Gtk::GLArea#use_es=.


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def use_es=(use_es : Bool) : Nil #

Sets whether the area should create an OpenGL or an OpenGL ES context.

You should check the capabilities of the Gdk::GLContext before drawing with either API.


[View source]
def use_es? : Bool #

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