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gtk2/gtk/gtkglarea.c
Matthias Clasen b2e121039e gl area: Add a few missing docs
2015-04-26 10:19:26 -04:00

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/* GTK - The GIMP Toolkit
*
* gtkglarea.c: A GL drawing area
*
* Copyright © 2014 Emmanuele Bassi
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "config.h"
#include "gtkglarea.h"
#include "gtkintl.h"
#include "gtkstylecontext.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkrender.h"
#include <epoxy/gl.h>
/**
* SECTION:gtkglarea
* @Title: GtkGLArea
* @Short_description: A widget for custom drawing with OpenGL
*
* #GtkGLArea is a widget that allows drawing with OpenGL.
*
* #GtkGLArea sets up its own #GdkGLContext for the window it creates, 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 #GtkGLArea::render signal,
* or subclass #GtkGLArea and override the @GtkGLAreaClass.render() virtual
* function.
*
* The #GtkGLArea widget ensures that the #GdkGLContext 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 GtkGLArea ##
*
* The simplest way to draw using OpenGL commands in a #GtkGLArea is to
* create a widget instance and connect to the #GtkGLArea::render signal:
*
* |[<!-- language="C" -->
* // create a GtkGLArea instance
* GtkWidget *gl_area = gtk_gl_area_new ();
*
* // connect to the "render" signal
* g_signal_connect (gl_area, "render", G_CALLBACK (render), NULL);
* ]|
*
* The `render()` function will be called when the #GtkGLArea is ready
* for you to draw its content:
*
* |[<!-- language="C" -->
* static gboolean
* render (GtkGLArea *area, GdkGLContext *context)
* {
* // inside this function it's safe to use GL; the given
* // #GdkGLContext has been made current to the drawable
* // surface used by the #GtkGLArea 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;
* }
* ]|
*
* If you need to initialize OpenGL state, e.g. buffer objects or
* shaders, you should use the #GtkWidget::realize signal; you
* can use the #GtkWidget::unrealize signal to clean up. Since the
* #GdkGLContext creation and initialization may fail, you will
* need to check for errors, using gtk_gl_area_get_error(). An example
* of how to safely initialize the GL state is:
*
* |[<!-- language="C" -->
* static void
* on_realize (GtkGLarea *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
* // GtkGLArea 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 #GdkGLContext
* you should use the #GtkGLArea::create-context signal.
*/
typedef struct {
GdkGLContext *context;
GdkWindow *event_window;
GError *error;
gboolean have_buffers;
int required_gl_version;
guint frame_buffer;
guint render_buffer;
guint texture;
guint depth_stencil_buffer;
gboolean has_alpha;
gboolean has_depth_buffer;
gboolean has_stencil_buffer;
gboolean needs_resize;
gboolean needs_render;
gboolean auto_render;
} GtkGLAreaPrivate;
enum {
PROP_0,
PROP_CONTEXT,
PROP_HAS_ALPHA,
PROP_HAS_DEPTH_BUFFER,
PROP_HAS_STENCIL_BUFFER,
PROP_AUTO_RENDER,
LAST_PROP
};
static GParamSpec *obj_props[LAST_PROP] = { NULL, };
enum {
RENDER,
RESIZE,
CREATE_CONTEXT,
LAST_SIGNAL
};
static void gtk_gl_area_allocate_buffers (GtkGLArea *area);
static guint area_signals[LAST_SIGNAL] = { 0, };
G_DEFINE_TYPE_WITH_PRIVATE (GtkGLArea, gtk_gl_area, GTK_TYPE_WIDGET)
static void
gtk_gl_area_dispose (GObject *gobject)
{
GtkGLArea *area = GTK_GL_AREA (gobject);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_clear_object (&priv->context);
G_OBJECT_CLASS (gtk_gl_area_parent_class)->dispose (gobject);
}
static void
gtk_gl_area_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GtkGLArea *self = GTK_GL_AREA (gobject);
switch (prop_id)
{
case PROP_AUTO_RENDER:
gtk_gl_area_set_auto_render (self, g_value_get_boolean (value));
break;
case PROP_HAS_ALPHA:
gtk_gl_area_set_has_alpha (self, g_value_get_boolean (value));
break;
case PROP_HAS_DEPTH_BUFFER:
gtk_gl_area_set_has_depth_buffer (self, g_value_get_boolean (value));
break;
case PROP_HAS_STENCIL_BUFFER:
gtk_gl_area_set_has_stencil_buffer (self, g_value_get_boolean (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
gtk_gl_area_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (GTK_GL_AREA (gobject));
switch (prop_id)
{
case PROP_AUTO_RENDER:
g_value_set_boolean (value, priv->auto_render);
break;
case PROP_HAS_ALPHA:
g_value_set_boolean (value, priv->has_alpha);
break;
case PROP_HAS_DEPTH_BUFFER:
g_value_set_boolean (value, priv->has_depth_buffer);
break;
case PROP_HAS_STENCIL_BUFFER:
g_value_set_boolean (value, priv->has_stencil_buffer);
break;
case PROP_CONTEXT:
g_value_set_object (value, priv->context);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
gtk_gl_area_realize (GtkWidget *widget)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GtkAllocation allocation;
GdkWindowAttr attributes;
gint attributes_mask;
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->realize (widget);
gtk_widget_get_allocation (widget, &allocation);
attributes.window_type = GDK_WINDOW_CHILD;
attributes.x = allocation.x;
attributes.y = allocation.y;
attributes.width = allocation.width;
attributes.height = allocation.height;
attributes.wclass = GDK_INPUT_ONLY;
attributes.event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;
attributes_mask = GDK_WA_X | GDK_WA_Y;
priv->event_window = gdk_window_new (gtk_widget_get_parent_window (widget),
&attributes, attributes_mask);
gtk_widget_register_window (widget, priv->event_window);
g_clear_error (&priv->error);
priv->context = NULL;
g_signal_emit (area, area_signals[CREATE_CONTEXT], 0, &priv->context);
/* In case the signal failed, but did not set an error */
if (priv->context == NULL && priv->error == NULL)
g_set_error_literal (&priv->error, GDK_GL_ERROR,
GDK_GL_ERROR_NOT_AVAILABLE,
_("OpenGL context creation failed"));
priv->needs_resize = TRUE;
}
static void
gtk_gl_area_notify (GObject *object,
GParamSpec *pspec)
{
if (strcmp (pspec->name, "scale-factor") == 0)
{
GtkGLArea *area = GTK_GL_AREA (object);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
priv->needs_resize = TRUE;
}
if (G_OBJECT_CLASS (gtk_gl_area_parent_class)->notify)
G_OBJECT_CLASS (gtk_gl_area_parent_class)->notify (object, pspec);
}
static GdkGLContext *
gtk_gl_area_real_create_context (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GtkWidget *widget = GTK_WIDGET (area);
GError *error = NULL;
GdkGLContext *context;
context = gdk_window_create_gl_context (gtk_widget_get_window (widget), &error);
if (error != NULL)
{
gtk_gl_area_set_error (area, error);
g_clear_object (&context);
g_clear_error (&error);
return NULL;
}
gdk_gl_context_set_required_version (context,
priv->required_gl_version / 10,
priv->required_gl_version % 10);
gdk_gl_context_realize (context, &error);
if (error != NULL)
{
gtk_gl_area_set_error (area, error);
g_clear_object (&context);
g_clear_error (&error);
return NULL;
}
return context;
}
static void
gtk_gl_area_resize (GtkGLArea *area, int width, int height)
{
glViewport (0, 0, width, height);
}
/*
* Creates all the buffer objects needed for rendering the scene
*/
static void
gtk_gl_area_ensure_buffers (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GtkWidget *widget = GTK_WIDGET (area);
gtk_widget_realize (widget);
if (priv->context == NULL)
return;
if (priv->have_buffers)
return;
priv->have_buffers = TRUE;
glGenFramebuffersEXT (1, &priv->frame_buffer);
if (priv->has_alpha)
{
/* For alpha we use textures as that is required for blending to work */
if (priv->texture == 0)
glGenTextures (1, &priv->texture);
/* Delete old render buffer if any */
if (priv->render_buffer != 0)
{
glDeleteRenderbuffersEXT(1, &priv->render_buffer);
priv->render_buffer = 0;
}
}
else
{
/* For non-alpha we use render buffers so we can blit instead of texture the result */
if (priv->render_buffer == 0)
glGenRenderbuffersEXT (1, &priv->render_buffer);
/* Delete old texture if any */
if (priv->texture != 0)
{
glDeleteTextures(1, &priv->texture);
priv->texture = 0;
}
}
if ((priv->has_depth_buffer || priv->has_stencil_buffer))
{
if (priv->depth_stencil_buffer == 0)
glGenRenderbuffersEXT (1, &priv->depth_stencil_buffer);
}
else if (priv->depth_stencil_buffer != 0)
{
/* Delete old depth/stencil buffer */
glDeleteRenderbuffersEXT (1, &priv->depth_stencil_buffer);
priv->depth_stencil_buffer = 0;
}
gtk_gl_area_allocate_buffers (area);
}
/*
* Allocates space of the right type and size for all the buffers
*/
static void
gtk_gl_area_allocate_buffers (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GtkWidget *widget = GTK_WIDGET (area);
int scale, width, height;
if (priv->context == NULL)
return;
scale = gtk_widget_get_scale_factor (widget);
width = gtk_widget_get_allocated_width (widget) * scale;
height = gtk_widget_get_allocated_height (widget) * scale;
if (priv->texture)
{
glBindTexture (GL_TEXTURE_2D, priv->texture);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
}
if (priv->render_buffer)
{
glBindRenderbuffer (GL_RENDERBUFFER, priv->render_buffer);
glRenderbufferStorage (GL_RENDERBUFFER, GL_RGB8, width, height);
}
if (priv->has_depth_buffer || priv->has_stencil_buffer)
{
glBindRenderbuffer (GL_RENDERBUFFER, priv->depth_stencil_buffer);
if (priv->has_stencil_buffer)
glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
else
glRenderbufferStorage (GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
}
priv->needs_render = TRUE;
}
/**
* gtk_gl_area_attach_buffers:
* @area: a #GtkGLArea
*
* 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 frambuffer.
*
* This function is automatically called before emitting the
* #GtkGLArea::render signal, and doesn't normally need to be called
* by application code.
*
* Since: 3.16
*/
void
gtk_gl_area_attach_buffers (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
if (priv->context == NULL)
return;
gtk_gl_area_make_current (area);
if (!priv->have_buffers)
gtk_gl_area_ensure_buffers (area);
else if (priv->needs_resize)
gtk_gl_area_allocate_buffers (area);
glBindFramebufferEXT (GL_FRAMEBUFFER_EXT, priv->frame_buffer);
if (priv->texture)
glFramebufferTexture2D (GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_TEXTURE_2D, priv->texture, 0);
else if (priv->render_buffer)
glFramebufferRenderbufferEXT (GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_RENDERBUFFER_EXT, priv->render_buffer);
if (priv->depth_stencil_buffer)
{
if (priv->has_depth_buffer)
glFramebufferRenderbufferEXT (GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, priv->depth_stencil_buffer);
if (priv->has_stencil_buffer)
glFramebufferRenderbufferEXT (GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, priv->depth_stencil_buffer);
}
}
static void
gtk_gl_area_delete_buffers (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
if (priv->context == NULL)
return;
priv->have_buffers = FALSE;
if (priv->render_buffer != 0)
{
glDeleteRenderbuffersEXT (1, &priv->render_buffer);
priv->render_buffer = 0;
}
if (priv->texture != 0)
{
glDeleteTextures(1, &priv->texture);
priv->texture = 0;
}
if (priv->depth_stencil_buffer != 0)
{
glDeleteRenderbuffersEXT (1, &priv->depth_stencil_buffer);
priv->depth_stencil_buffer = 0;
}
if (priv->frame_buffer != 0)
{
glBindFramebufferEXT (GL_FRAMEBUFFER_EXT, 0);
glDeleteFramebuffersEXT (1, &priv->frame_buffer);
priv->frame_buffer = 0;
}
}
static void
gtk_gl_area_unrealize (GtkWidget *widget)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
if (priv->context != NULL)
{
if (priv->have_buffers)
{
gtk_gl_area_make_current (area);
gtk_gl_area_delete_buffers (area);
}
/* Make sure to unset the context if current */
if (priv->context == gdk_gl_context_get_current ())
gdk_gl_context_clear_current ();
}
g_clear_object (&priv->context);
g_clear_error (&priv->error);
if (priv->event_window != NULL)
{
gtk_widget_unregister_window (widget, priv->event_window);
gdk_window_destroy (priv->event_window);
priv->event_window = NULL;
}
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->unrealize (widget);
}
static void
gtk_gl_area_map (GtkWidget *widget)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
if (priv->event_window != NULL)
gdk_window_show (priv->event_window);
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->map (widget);
}
static void
gtk_gl_area_unmap (GtkWidget *widget)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
if (priv->event_window != NULL)
gdk_window_hide (priv->event_window);
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->unmap (widget);
}
static void
gtk_gl_area_size_allocate (GtkWidget *widget,
GtkAllocation *allocation)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->size_allocate (widget, allocation);
if (gtk_widget_get_realized (widget))
{
if (priv->event_window != NULL)
gdk_window_move_resize (priv->event_window,
allocation->x,
allocation->y,
allocation->width,
allocation->height);
priv->needs_resize = TRUE;
}
}
static void
gtk_gl_area_draw_error_screen (GtkGLArea *area,
cairo_t *cr,
gint width,
gint height)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
PangoLayout *layout;
int layout_height;
layout = gtk_widget_create_pango_layout (GTK_WIDGET (area),
priv->error->message);
pango_layout_set_width (layout, width * PANGO_SCALE);
pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);
pango_layout_get_pixel_size (layout, NULL, &layout_height);
gtk_render_layout (gtk_widget_get_style_context (GTK_WIDGET (area)),
cr,
0, (height - layout_height) / 2,
layout);
g_object_unref (layout);
}
static gboolean
gtk_gl_area_draw (GtkWidget *widget,
cairo_t *cr)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
gboolean unused;
int w, h, scale;
GLenum status;
if (priv->error != NULL)
{
gtk_gl_area_draw_error_screen (area,
cr,
gtk_widget_get_allocated_width (widget),
gtk_widget_get_allocated_height (widget));
return FALSE;
}
if (priv->context == NULL)
return FALSE;
gtk_gl_area_make_current (area);
gtk_gl_area_attach_buffers (area);
if (priv->has_depth_buffer)
glEnable (GL_DEPTH_TEST);
else
glDisable (GL_DEPTH_TEST);
scale = gtk_widget_get_scale_factor (widget);
w = gtk_widget_get_allocated_width (widget) * scale;
h = gtk_widget_get_allocated_height (widget) * scale;
status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if (status == GL_FRAMEBUFFER_COMPLETE_EXT)
{
if (priv->needs_render || priv->auto_render)
{
if (priv->needs_resize)
{
g_signal_emit (area, area_signals[RESIZE], 0, w, h, NULL);
priv->needs_resize = FALSE;
}
g_signal_emit (area, area_signals[RENDER], 0, priv->context, &unused);
}
priv->needs_render = FALSE;
gdk_cairo_draw_from_gl (cr,
gtk_widget_get_window (widget),
priv->texture ? priv->texture : priv->render_buffer,
priv->texture ? GL_TEXTURE : GL_RENDERBUFFER,
scale, 0, 0, w, h);
gtk_gl_area_make_current (area);
}
else
{
g_print ("fb setup not supported\n");
}
return TRUE;
}
static gboolean
create_context_accumulator (GSignalInvocationHint *ihint,
GValue *return_accu,
const GValue *handler_return,
gpointer data)
{
g_value_copy (handler_return, return_accu);
/* stop after the first handler returning a valid object */
return g_value_get_object (handler_return) == NULL;
}
static void
gtk_gl_area_class_init (GtkGLAreaClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
klass->resize = gtk_gl_area_resize;
klass->create_context = gtk_gl_area_real_create_context;
widget_class->realize = gtk_gl_area_realize;
widget_class->unrealize = gtk_gl_area_unrealize;
widget_class->map = gtk_gl_area_map;
widget_class->unmap = gtk_gl_area_unmap;
widget_class->size_allocate = gtk_gl_area_size_allocate;
widget_class->draw = gtk_gl_area_draw;
gtk_widget_class_set_accessible_role (widget_class, ATK_ROLE_DRAWING_AREA);
/**
* GtkGLArea:context:
*
* The #GdkGLContext used by the #GtkGLArea widget.
*
* The #GtkGLArea widget is responsible for creating the #GdkGLContext
* instance. If you need to render with other kinds of buffers (stencil,
* depth, etc), use render buffers.
*
* Since: 3.16
*/
obj_props[PROP_CONTEXT] =
g_param_spec_object ("context",
P_("Context"),
P_("The GL context"),
GDK_TYPE_GL_CONTEXT,
G_PARAM_READABLE |
G_PARAM_STATIC_STRINGS);
/**
* GtkGLArea:auto-render:
*
* If set to %TRUE the #GtkGLArea::render signal will be emitted every time
* the widget draws. This is the default and is useful if drawing the widget
* is faster.
*
* If set to %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_gl_area_queue_render() must be called.
* This mode is useful when the scene changes seldomly, but takes a long time
* to redraw.
*
* Since: 3.16
*/
obj_props[PROP_AUTO_RENDER] =
g_param_spec_boolean ("auto-render",
P_("Auto render"),
P_("Whether the GtkGLArea renders on each redraw"),
TRUE,
GTK_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkGLArea:has-alpha:
*
* If set to %TRUE the buffer allocated by the widget will have an alpha channel
* component, and when rendering to the window the result will be composited over
* whatever is below the widget.
*
* If set to %FALSE there will be no alpha channel, and the buffer will fully
* replace anything below the widget.
*
* Since: 3.16
*/
obj_props[PROP_HAS_ALPHA] =
g_param_spec_boolean ("has-alpha",
P_("Has alpha"),
P_("Whether the color buffer has an alpha component"),
FALSE,
GTK_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkGLArea:has-depth-buffer:
*
* If set to %TRUE the widget will allocate and enable a depth buffer for the
* target framebuffer.
*
* Since: 3.16
*/
obj_props[PROP_HAS_DEPTH_BUFFER] =
g_param_spec_boolean ("has-depth-buffer",
P_("Has depth buffer"),
P_("Whether a depth buffer is allocated"),
FALSE,
GTK_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
/**
* GtkGLArea:has-stencil-buffer:
*
* If set to %TRUE the widget will allocate and enable a stencil buffer for the
* target framebuffer.
*
* Since: 3.16
*/
obj_props[PROP_HAS_STENCIL_BUFFER] =
g_param_spec_boolean ("has-stencil-buffer",
P_("Has stencil buffer"),
P_("Whether a stencil buffer is allocated"),
FALSE,
GTK_PARAM_READWRITE |
G_PARAM_STATIC_STRINGS |
G_PARAM_EXPLICIT_NOTIFY);
gobject_class->set_property = gtk_gl_area_set_property;
gobject_class->get_property = gtk_gl_area_get_property;
gobject_class->dispose = gtk_gl_area_dispose;
gobject_class->notify = gtk_gl_area_notify;
g_object_class_install_properties (gobject_class, LAST_PROP, obj_props);
/**
* GtkGLArea::render:
* @area: the #GtkGLArea that emitted the signal
* @context: the #GdkGLContext used by @area
*
* The ::render signal is emitted every time the contents
* of the #GtkGLArea should be redrawn.
*
* The @context is bound to the @area prior to emitting this function,
* and the buffers are painted to the window once the emission terminates.
*
* Returns: %TRUE to stop other handlers from being invoked for the event.
* %FALSE to propagate the event further.
*
* Since: 3.16
*/
area_signals[RENDER] =
g_signal_new (I_("render"),
G_TYPE_FROM_CLASS (gobject_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGLAreaClass, render),
_gtk_boolean_handled_accumulator, NULL,
NULL,
G_TYPE_BOOLEAN, 1,
GDK_TYPE_GL_CONTEXT);
/**
* GtkGLArea::resize:
* @area: the #GtkGLArea that emitted the signal
*
* The ::resize signal is emitted once when the widget is realized, and
* then each time the widget is changed while realized. This is useful
* in order to keep GL state up to date with the widget size, like for
* instance camera properties which may depend on the width/height ratio.
*
* The GL context for the area is guaranteed to be current when this signal
* is emitted.
*
* The default handler sets up the GL viewport.
*
* Since: 3.16
*/
area_signals[RESIZE] =
g_signal_new ("resize",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGLAreaClass, resize),
NULL, NULL,
_gtk_marshal_VOID__INT_INT,
G_TYPE_NONE, 2, G_TYPE_INT, G_TYPE_INT);
/**
* GtkGLArea::create-context:
* @area: the #GtkGLArea that emitted the signal
* @error: (allow-none): location to store error information on failure
*
* The ::create-context signal is emitted when the widget is being
* realized, and allows you to override how the GL context is
* created. This is useful when you want to reuse an existing GL
* context, or if you want to try creating different kinds of GL
* options.
*
* If context creation fails then the signal handler can use
* gtk_gl_area_set_error() to register a more detailed error
* of how the construction failed.
*
* Returns: (transfer full): a newly created #GdkGLContext;
* the #GtkGLArea widget will take ownership of the returned value.
*
* Since: 3.16
*/
area_signals[CREATE_CONTEXT] =
g_signal_new ("create-context",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkGLAreaClass, create_context),
create_context_accumulator, NULL,
_gtk_marshal_OBJECT__VOID,
GDK_TYPE_GL_CONTEXT, 0);
}
static void
gtk_gl_area_init (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
gtk_widget_set_has_window (GTK_WIDGET (area), FALSE);
gtk_widget_set_app_paintable (GTK_WIDGET (area), TRUE);
priv->auto_render = TRUE;
priv->needs_render = TRUE;
priv->required_gl_version = 0;
}
/**
* gtk_gl_area_new:
*
* Creates a new #GtkGLArea widget.
*
* Returns: (transfer full): the newly created #GtkGLArea
*
* Since: 3.16
*/
GtkWidget *
gtk_gl_area_new (void)
{
return g_object_new (GTK_TYPE_GL_AREA, NULL);
}
/**
* gtk_gl_area_set_error:
* @area: a #GtkGLArea
* @error: (allow-none): a new #GError, or %NULL to unset the error
*
* Sets an error on the area which will be shown instead of the
* GL rendering. This is useful in the #GtkGLArea::create-context
* signal if GL context creation fails.
*
* Since: 3.16
*/
void
gtk_gl_area_set_error (GtkGLArea *area,
const GError *error)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
g_clear_error (&priv->error);
if (error)
priv->error = g_error_copy (error);
}
/**
* gtk_gl_area_get_error:
* @area: a #GtkGLArea
*
* Gets the current error set on the @area.
*
* Returns: (transfer none): the #GError or %NULL
*
* Since: 3.16
*/
GError *
gtk_gl_area_get_error (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), NULL);
return priv->error;
}
/**
* gtk_gl_area_set_required_version:
* @area: a #GtkGLArea
* @major: the major version
* @minor: the minor version
*
* 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.
*
* Since: 3.16
*/
void
gtk_gl_area_set_required_version (GtkGLArea *area,
gint major,
gint minor)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
g_return_if_fail (!gtk_widget_get_realized (GTK_WIDGET (area)));
priv->required_gl_version = major * 10 + minor;
}
/**
* gtk_gl_area_get_required_version:
* @area: a #GtkGLArea
* @major: (out): return location for the required major version
* @minor: (out): return location for the required minor version
*
* Retrieves the required version of OpenGL set
* using gtk_gl_area_set_required_version().
*
* Since: 3.16
*/
void
gtk_gl_area_get_required_version (GtkGLArea *area,
gint *major,
gint *minor)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
if (major != NULL)
*major = priv->required_gl_version / 10;
if (minor != NULL)
*minor = priv->required_gl_version % 10;
}
/**
* gtk_gl_area_get_has_alpha:
* @area: a #GtkGLArea
*
* Returns whether the area has an alpha component.
*
* Returns: %TRUE if the @area has an alpha component, %FALSE otherwise
*
* Since: 3.16
*/
gboolean
gtk_gl_area_get_has_alpha (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), FALSE);
return priv->has_alpha;
}
/**
* gtk_gl_area_set_has_alpha:
* @area: a #GtkGLArea
* @has_alpha: %TRUE to add an alpha component
*
* If @has_alpha is %TRUE the buffer allocated by the widget will have
* an alpha channel component, and when rendering to the window the
* result will be composited over whatever is below the widget.
*
* If @has_alpha is %FALSE there will be no alpha channel, and the
* buffer will fully replace anything below the widget.
*
* Since: 3.16
*/
void
gtk_gl_area_set_has_alpha (GtkGLArea *area,
gboolean has_alpha)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
has_alpha = !!has_alpha;
if (priv->has_alpha != has_alpha)
{
priv->has_alpha = has_alpha;
g_object_notify (G_OBJECT (area), "has-alpha");
gtk_gl_area_delete_buffers (area);
}
}
/**
* gtk_gl_area_get_has_depth_buffer:
* @area: a #GtkGLArea
*
* Returns whether the area has a depth buffer.
*
* Returns: %TRUE if the @area has a depth buffer, %FALSE otherwise
*
* Since: 3.16
*/
gboolean
gtk_gl_area_get_has_depth_buffer (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), FALSE);
return priv->has_depth_buffer;
}
/**
* gtk_gl_area_set_has_depth_buffer:
* @area: a #GtkGLArea
* @has_depth_buffer: %TRUE to add 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.
*
* Since: 3.16
*/
void
gtk_gl_area_set_has_depth_buffer (GtkGLArea *area,
gboolean has_depth_buffer)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
has_depth_buffer = !!has_depth_buffer;
if (priv->has_depth_buffer != has_depth_buffer)
{
priv->has_depth_buffer = has_depth_buffer;
g_object_notify (G_OBJECT (area), "has-depth-buffer");
priv->have_buffers = FALSE;
}
}
/**
* gtk_gl_area_get_has_stencil_buffer:
* @area: a #GtkGLArea
*
* Returns whether the area has a stencil buffer.
*
* Returns: %TRUE if the @area has a stencil buffer, %FALSE otherwise
*
* Since: 3.16
*/
gboolean
gtk_gl_area_get_has_stencil_buffer (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), FALSE);
return priv->has_stencil_buffer;
}
/**
* gtk_gl_area_set_has_stencil_buffer:
* @area: a #GtkGLArea
* @has_stencil_buffer: %TRUE to add 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.
*
* Since: 3.16
*/
void
gtk_gl_area_set_has_stencil_buffer (GtkGLArea *area,
gboolean has_stencil_buffer)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
has_stencil_buffer = !!has_stencil_buffer;
if (priv->has_stencil_buffer != has_stencil_buffer)
{
priv->has_stencil_buffer = has_stencil_buffer;
g_object_notify (G_OBJECT (area), "has-stencil-buffer");
priv->have_buffers = FALSE;
}
}
/**
* gtk_gl_area_queue_render:
* @area: a #GtkGLArea
*
* Marks the currently rendered data (if any) as invalid, and queues
* a redraw of the widget, ensuring that the #GtkGLArea::render signal
* is emitted during the draw.
*
* This is only needed when the gtk_gl_area_set_auto_render() has
* been called with a %FALSE value. The default behaviour is to
* emit #GtkGLArea::render on each draw.
*
* Since: 3.16
*/
void
gtk_gl_area_queue_render (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
priv->needs_render = TRUE;
gtk_widget_queue_draw (GTK_WIDGET (area));
}
/**
* gtk_gl_area_get_auto_render:
* @area: a #GtkGLArea
*
* Returns whether the area is in auto render mode or not.
*
* Returns: %TRUE if the @area is auto rendering, %FALSE otherwise
*
* Since: 3.16
*/
gboolean
gtk_gl_area_get_auto_render (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), FALSE);
return priv->auto_render;
}
/**
* gtk_gl_area_set_auto_render:
* @area: a #GtkGLArea
* @auto_render: a boolean
*
* If @auto_render is %TRUE the #GtkGLArea::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_gl_area_queue_render() must be called. This mode is useful when
* the scene changes seldomly, but takes a long time to redraw.
*
* Since: 3.16
*/
void
gtk_gl_area_set_auto_render (GtkGLArea *area,
gboolean auto_render)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_if_fail (GTK_IS_GL_AREA (area));
auto_render = !!auto_render;
if (priv->auto_render != auto_render)
{
priv->auto_render = auto_render;
g_object_notify (G_OBJECT (area), "auto-render");
if (auto_render)
gtk_widget_queue_draw (GTK_WIDGET (area));
}
}
/**
* gtk_gl_area_get_context:
* @area: a #GtkGLArea
*
* Retrieves the #GdkGLContext used by @area.
*
* Returns: (transfer none): the #GdkGLContext
*
* Since: 3.16
*/
GdkGLContext *
gtk_gl_area_get_context (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), NULL);
return priv->context;
}
/**
* gtk_gl_area_make_current:
* @area: a #GtkGLArea
*
* Ensures that the #GdkGLContext used by @area is associated with
* the #GtkGLArea.
*
* This function is automatically called before emitting the
* #GtkGLArea::render signal, and doesn't normally need to be called
* by application code.
*
* Since: 3.16
*/
void
gtk_gl_area_make_current (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
GtkWidget *widget;
g_return_if_fail (GTK_IS_GL_AREA (area));
widget = GTK_WIDGET (area);
g_return_if_fail (gtk_widget_get_realized (widget));
if (priv->context != NULL)
gdk_gl_context_make_current (priv->context);
}
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