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gtk/gtk/gtkglarea.c
Emmanuele Bassi 8a6dd2805f Document side effect of GLArea:has-depth-buffer 
We enable depth testing when creating a depth buffer.

Fixes: #838
2022-01-07 18:30:54 +00:00

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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 "gtkmarshalers.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkrender.h"
#include "gtksnapshot.h"
#include "gtknative.h"
#include "gtkwidgetprivate.h"
#include <epoxy/gl.h>
/**
* GtkGLArea:
*
* `GtkGLArea` is a widget that allows drawing with OpenGL.
*
* ![An example GtkGLArea](glarea.png)
*
* `GtkGLArea` sets up its own [class@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 [signal@Gtk.GLArea::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 [signal@Gtk.GLArea::render] signal:
*
* The `render()` function will be called when the `GtkGLArea` is ready
* for you to draw its content:
*
* ```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;
* }
*
* void setup_glarea (void)
* {
* // 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);
* }
* ```
*
* If you need to initialize OpenGL state, e.g. buffer objects or
* shaders, you should use the [signal@Gtk.Widget::realize] signal;
* you can use the [signal@Gtk.Widget::unrealize] signal to clean up.
* Since the `GdkGLContext` creation and initialization may fail, you
* will need to check for errors, using [method@Gtk.GLArea.get_error].
*
* An example of how to safely initialize the GL state is:
*
* ```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 [signal@Gtk.GLArea::create-context] signal.
*/
typedef struct {
guint id;
int width;
int height;
GdkTexture *holder;
} Texture;
typedef struct {
GdkGLContext *context;
GError *error;
gboolean have_buffers;
int required_gl_version;
guint frame_buffer;
guint depth_stencil_buffer;
Texture *texture;
GList *textures;
gboolean has_depth_buffer;
gboolean has_stencil_buffer;
gboolean needs_resize;
gboolean needs_render;
gboolean auto_render;
gboolean use_es;
} GtkGLAreaPrivate;
enum {
PROP_0,
PROP_CONTEXT,
PROP_HAS_DEPTH_BUFFER,
PROP_HAS_STENCIL_BUFFER,
PROP_USE_ES,
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 void gtk_gl_area_allocate_texture (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_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_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;
case PROP_USE_ES:
gtk_gl_area_set_use_es (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_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;
case PROP_USE_ES:
g_value_set_boolean (value, priv->use_es);
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);
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->realize (widget);
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_surface_create_gl_context (gtk_native_get_surface (gtk_widget_get_native (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_allowed_apis (context, priv->use_es ? GDK_GL_API_GLES : GDK_GL_API_GL);
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;
glGenFramebuffers (1, &priv->frame_buffer);
if ((priv->has_depth_buffer || priv->has_stencil_buffer))
{
if (priv->depth_stencil_buffer == 0)
glGenRenderbuffers (1, &priv->depth_stencil_buffer);
}
else if (priv->depth_stencil_buffer != 0)
{
/* Delete old depth/stencil buffer */
glDeleteRenderbuffers (1, &priv->depth_stencil_buffer);
priv->depth_stencil_buffer = 0;
}
gtk_gl_area_allocate_buffers (area);
}
static void
delete_one_texture (gpointer data)
{
Texture *texture = data;
if (texture->holder)
gdk_gl_texture_release (GDK_GL_TEXTURE (texture->holder));
if (texture->id != 0)
{
glDeleteTextures (1, &texture->id);
texture->id = 0;
}
g_free (texture);
}
static void
gtk_gl_area_ensure_texture (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->texture == NULL)
{
GList *l, *link;
l = priv->textures;
while (l)
{
Texture *texture = l->data;
link = l;
l = l->next;
if (texture->holder)
continue;
priv->textures = g_list_delete_link (priv->textures, link);
if (priv->texture == NULL)
priv->texture = texture;
else
delete_one_texture (texture);
}
}
if (priv->texture == NULL)
{
priv->texture = g_new (Texture, 1);
priv->texture->width = 0;
priv->texture->height = 0;
priv->texture->holder = NULL;
glGenTextures (1, &priv->texture->id);
}
gtk_gl_area_allocate_texture (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_width (widget) * scale;
height = gtk_widget_get_height (widget) * scale;
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;
}
static void
gtk_gl_area_allocate_texture (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;
if (priv->texture == NULL)
return;
g_assert (priv->texture->holder == NULL);
scale = gtk_widget_get_scale_factor (widget);
width = gtk_widget_get_width (widget) * scale;
height = gtk_widget_get_height (widget) * scale;
if (priv->texture->width != width ||
priv->texture->height != height)
{
glBindTexture (GL_TEXTURE_2D, priv->texture->id);
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);
if (gdk_gl_context_get_use_es (priv->context))
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
else
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
priv->texture->width = width;
priv->texture->height = height;
}
}
/**
* gtk_gl_area_attach_buffers:
* @area: a `GtkGLArea`
*
* 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
* [signal@Gtk.GLArea::render] signal, and doesn't normally need to be
* called by application code.
*/
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->texture == NULL)
gtk_gl_area_ensure_texture (area);
else if (priv->needs_resize)
gtk_gl_area_allocate_texture (area);
if (!priv->have_buffers)
gtk_gl_area_ensure_buffers (area);
else if (priv->needs_resize)
gtk_gl_area_allocate_buffers (area);
glBindFramebuffer (GL_FRAMEBUFFER, priv->frame_buffer);
if (priv->texture != NULL)
glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, priv->texture->id, 0);
if (priv->depth_stencil_buffer)
{
if (priv->has_depth_buffer)
glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, priv->depth_stencil_buffer);
if (priv->has_stencil_buffer)
glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
GL_RENDERBUFFER, 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->depth_stencil_buffer != 0)
{
glDeleteRenderbuffers (1, &priv->depth_stencil_buffer);
priv->depth_stencil_buffer = 0;
}
if (priv->frame_buffer != 0)
{
glBindFramebuffer (GL_FRAMEBUFFER, 0);
glDeleteFramebuffers (1, &priv->frame_buffer);
priv->frame_buffer = 0;
}
}
static void
gtk_gl_area_delete_textures (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
if (priv->texture)
{
delete_one_texture (priv->texture);
priv->texture = NULL;
}
/* FIXME: we need to explicitly release all outstanding
* textures here, otherwise release_texture will get called
* later and access freed memory.
*/
g_list_free_full (priv->textures, delete_one_texture);
priv->textures = NULL;
}
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)
{
gtk_gl_area_make_current (area);
gtk_gl_area_delete_buffers (area);
gtk_gl_area_delete_textures (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);
GTK_WIDGET_CLASS (gtk_gl_area_parent_class)->unrealize (widget);
}
static void
gtk_gl_area_size_allocate (GtkWidget *widget,
int width,
int height,
int baseline)
{
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, width, height, baseline);
if (gtk_widget_get_realized (widget))
priv->needs_resize = TRUE;
}
static void
gtk_gl_area_draw_error_screen (GtkGLArea *area,
GtkSnapshot *snapshot,
int width,
int 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_snapshot_render_layout (snapshot,
gtk_widget_get_style_context (GTK_WIDGET (area)),
0, (height - layout_height) / 2,
layout);
g_object_unref (layout);
}
static void
release_texture (gpointer data)
{
Texture *texture = data;
texture->holder = NULL;
}
static void
gtk_gl_area_snapshot (GtkWidget *widget,
GtkSnapshot *snapshot)
{
GtkGLArea *area = GTK_GL_AREA (widget);
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
gboolean unused;
int w, h, scale;
GLenum status;
scale = gtk_widget_get_scale_factor (widget);
w = gtk_widget_get_width (widget) * scale;
h = gtk_widget_get_height (widget) * scale;
if (w == 0 || h == 0)
return;
if (priv->error != NULL)
{
gtk_gl_area_draw_error_screen (area,
snapshot,
gtk_widget_get_width (widget),
gtk_widget_get_height (widget));
return;
}
if (priv->context == NULL)
return;
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);
status = glCheckFramebufferStatus (GL_FRAMEBUFFER);
if (status == GL_FRAMEBUFFER_COMPLETE)
{
Texture *texture;
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;
texture = priv->texture;
priv->texture = NULL;
priv->textures = g_list_prepend (priv->textures, texture);
texture->holder = gdk_gl_texture_new (priv->context,
texture->id,
texture->width,
texture->height,
release_texture, texture);
/* Our texture is rendered by OpenGL, so it is upside down,
* compared to what GSK expects, so flip it back.
*/
gtk_snapshot_save (snapshot);
gtk_snapshot_translate (snapshot, &GRAPHENE_POINT_INIT (0, gtk_widget_get_height (widget)));
gtk_snapshot_scale (snapshot, 1, -1);
gtk_snapshot_append_texture (snapshot,
texture->holder,
&GRAPHENE_RECT_INIT (0, 0,
gtk_widget_get_width (widget),
gtk_widget_get_height (widget)));
gtk_snapshot_restore (snapshot);
g_object_unref (texture->holder);
}
else
{
g_warning ("fb setup not supported (%x)", status);
}
}
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->size_allocate = gtk_gl_area_size_allocate;
widget_class->snapshot = gtk_gl_area_snapshot;
/**
* 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.
*/
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: (attributes org.gtk.Property.get=gtk_gl_area_get_auto_render org.gtk.Property.set=gtk_gl_area_set_auto_render)
*
* If set to %TRUE the ::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 [method@Gtk.GLArea.queue_render] must be called.
* This mode is useful when the scene changes seldom, but takes a long time
* to redraw.
*/
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-depth-buffer: (attributes org.gtk.Property.get=gtk_gl_area_get_has_depth_buffer org.gtk.Property.set=gtk_gl_area_set_has_depth_buffer)
*
* If set to %TRUE the widget will allocate and enable a depth buffer for the
* target framebuffer.
*
* Setting this property will enable GL's depth testing as a side effect. If
* you don't need depth testing, you should call `glDisable(GL_DEPTH_TEST)`
* in your `GtkGLArea::render` handler.
*/
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: (attributes org.gtk.Property.get=gtk_gl_area_get_has_stencil_buffer org.gtk.Property.set=gtk_gl_area_set_has_stencil_buffer)
*
* If set to %TRUE the widget will allocate and enable a stencil buffer for the
* target framebuffer.
*/
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);
/**
* GtkGLArea:use-es: (attributes org.gtk.Property.get=gtk_gl_area_get_use_es org.gtk.Property.set=gtk_gl_area_set_use_es)
*
* If set to %TRUE the widget will try to create a `GdkGLContext` using
* OpenGL ES instead of OpenGL.
*/
obj_props[PROP_USE_ES] =
g_param_spec_boolean ("use-es",
P_("Use OpenGL ES"),
P_("Whether the context uses OpenGL or OpenGL ES"),
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->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
*
* 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.
*/
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,
_gtk_marshal_BOOLEAN__OBJECT,
G_TYPE_BOOLEAN, 1,
GDK_TYPE_GL_CONTEXT);
g_signal_set_va_marshaller (area_signals[RENDER],
G_TYPE_FROM_CLASS (klass),
_gtk_marshal_BOOLEAN__OBJECTv);
/**
* GtkGLArea::resize:
* @area: the `GtkGLArea` that emitted the signal
* @width: the width of the viewport
* @height: the height of the viewport
*
* 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.
*/
area_signals[RESIZE] =
g_signal_new (I_("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);
g_signal_set_va_marshaller (area_signals[RESIZE],
G_TYPE_FROM_CLASS (klass),
_gtk_marshal_VOID__INT_INTv);
/**
* GtkGLArea::create-context:
* @area: the `GtkGLArea` that emitted the signal
* @error: (nullable): location to store error information on failure
*
* Emitted when the widget is being realized.
*
* This 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
* [method@Gtk.GLArea.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.
*/
area_signals[CREATE_CONTEXT] =
g_signal_new (I_("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);
g_signal_set_va_marshaller (area_signals[CREATE_CONTEXT],
G_TYPE_FROM_CLASS (klass),
_gtk_marshal_OBJECT__VOIDv);
}
static void
gtk_gl_area_init (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
priv->auto_render = TRUE;
priv->needs_render = TRUE;
priv->required_gl_version = 0;
}
/**
* gtk_gl_area_new:
*
* Creates a new `GtkGLArea` widget.
*
* Returns: a new `GtkGLArea`
*/
GtkWidget *
gtk_gl_area_new (void)
{
return g_object_new (GTK_TYPE_GL_AREA, NULL);
}
/**
* gtk_gl_area_set_error:
* @area: a `GtkGLArea`
* @error: (nullable): 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 [signal@Gtk.GLArea::create-context]
* signal if GL context creation fails.
*/
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: (nullable) (transfer none): the `GError`
*/
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_use_es: (attributes org.gtk.Method.set_property=use-es)
* @area: a `GtkGLArea`
* @use_es: whether to use OpenGL or OpenGL ES
*
* Sets whether the @area should create an OpenGL or an OpenGL ES context.
*
* You should check the capabilities of the `GdkGLContext` before drawing
* with either API.
*/
void
gtk_gl_area_set_use_es (GtkGLArea *area,
gboolean use_es)
{
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)));
use_es = !!use_es;
if (priv->use_es != use_es)
{
priv->use_es = use_es;
g_object_notify_by_pspec (G_OBJECT (area), obj_props[PROP_USE_ES]);
}
}
/**
* gtk_gl_area_get_use_es: (attributes org.gtk.Method.get_property=use-es)
* @area: a `GtkGLArea`
*
* Returns whether the `GtkGLArea` should use OpenGL ES.
*
* See [method@Gtk.GLArea.set_use_es].
*
* Returns: %TRUE if the `GtkGLArea` should create an OpenGL ES context
* and %FALSE otherwise
*/
gboolean
gtk_gl_area_get_use_es (GtkGLArea *area)
{
GtkGLAreaPrivate *priv = gtk_gl_area_get_instance_private (area);
g_return_val_if_fail (GTK_IS_GL_AREA (area), FALSE);
return priv->use_es;
}
/**
* 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.
*/
void
gtk_gl_area_set_required_version (GtkGLArea *area,
int major,
int 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.
*
* See [method@Gtk.GLArea.set_required_version].
*/
void
gtk_gl_area_get_required_version (GtkGLArea *area,
int *major,
int *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_depth_buffer: (attributes org.gtk.Method.get_property=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
*/
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: (attributes org.gtk.Method.set_property=has-depth-buffer)
* @area: a `GtkGLArea`
* @has_depth_buffer: %TRUE to add a depth buffer
*
* Sets whether the `GtkGLArea` 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.
*/
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: (attributes org.gtk.Method.get_property=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
*/
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: (attributes org.gtk.Method.set_property=has-stencil-buffer)
* @area: a `GtkGLArea`
* @has_stencil_buffer: %TRUE to add a stencil buffer
*
* Sets whether the `GtkGLArea` 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.
*/
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.
*
* This ensures that the [signal@Gtk.GLArea::render] signal
* is emitted during the draw.
*
* This is only needed when [method@Gtk.GLArea.set_auto_render] has
* been called with a %FALSE value. The default behaviour is to
* emit [signal@Gtk.GLArea::render] on each draw.
*/
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: (attributes org.gtk.Method.get_property=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
*/
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: (attributes org.gtk.Method.set_property=auto-render)
* @area: a `GtkGLArea`
* @auto_render: a boolean
*
* Sets whether the `GtkGLArea` is in auto render mode.
*
* If @auto_render is %TRUE the [signal@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
* [method@Gtk.GLArea.queue_render] must be called. This mode is
* useful when the scene changes seldom, but takes a long time to redraw.
*/
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) (nullable): the `GdkGLContext`
*/
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
* [signal@Gtk.GLArea::render] signal, and doesn't normally need
* to be called by application code.
*/
void
gtk_gl_area_make_current (GtkGLArea *area)
{
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)));
if (priv->context != NULL)
gdk_gl_context_make_current (priv->context);
}
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