Learning_GTK4_tree/demos/gtk-demo/gskshaderpaintable.c

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2023-12-12 11:36:42 +01:00
/*
* Copyright © 2020 Red Hat, Inc
*
* 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 2.1 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/>.
*
* Authors: Matthias Clasen <mclasen@redhat.com>
*/
#include "config.h"
#include <gtk/gtk.h>
#include "gskshaderpaintable.h"
/**
* GskShaderPaintable:
*
* `GskShaderPaintable` is an implementation of the `GdkPaintable` interface
* that uses a `GskGLShader` to create pixels.
*
* You can set the uniform data that the shader needs for rendering
* using gsk_shader_paintable_set_args(). This function can
* be called repeatedly to change the uniform data for the next
* snapshot.
*
* Commonly, time is passed to shaders as a float uniform containing
* the elapsed time in seconds. The convenience API
* gsk_shader_paintable_update_time() can be called from a `GtkTickCallback`
* to update the time based on the frame time of the frame clock.
*/
struct _GskShaderPaintable
{
GObject parent_instance;
GskGLShader *shader;
GBytes *args;
gint64 start_time;
};
struct _GskShaderPaintableClass
{
GObjectClass parent_class;
};
enum {
PROP_0,
PROP_SHADER,
PROP_ARGS,
N_PROPS,
};
static GParamSpec *properties[N_PROPS] = { NULL, };
static void
gsk_shader_paintable_paintable_snapshot (GdkPaintable *paintable,
GdkSnapshot *snapshot,
double width,
double height)
{
GskShaderPaintable *self = GSK_SHADER_PAINTABLE (paintable);
gtk_snapshot_push_gl_shader (snapshot, self->shader, &GRAPHENE_RECT_INIT(0, 0, width, height), g_bytes_ref (self->args));
gtk_snapshot_pop (snapshot);
}
static void
gsk_shader_paintable_paintable_init (GdkPaintableInterface *iface)
{
iface->snapshot = gsk_shader_paintable_paintable_snapshot;
}
G_DEFINE_TYPE_EXTENDED (GskShaderPaintable, gsk_shader_paintable, G_TYPE_OBJECT, 0,
G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
gsk_shader_paintable_paintable_init))
static void
gsk_shader_paintable_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GskShaderPaintable *self = GSK_SHADER_PAINTABLE (object);
switch (prop_id)
{
case PROP_SHADER:
gsk_shader_paintable_set_shader (self, g_value_get_object (value));
break;
case PROP_ARGS:
gsk_shader_paintable_set_args (self, g_value_get_boxed (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gsk_shader_paintable_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GskShaderPaintable *self = GSK_SHADER_PAINTABLE (object);
switch (prop_id)
{
case PROP_SHADER:
g_value_set_object (value, self->shader);
break;
case PROP_ARGS:
g_value_set_boxed (value, self->args);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gsk_shader_paintable_finalize (GObject *object)
{
GskShaderPaintable *self = GSK_SHADER_PAINTABLE (object);
g_clear_pointer (&self->args, g_bytes_unref);
g_clear_object (&self->shader);
G_OBJECT_CLASS (gsk_shader_paintable_parent_class)->finalize (object);
}
static void
gsk_shader_paintable_class_init (GskShaderPaintableClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->get_property = gsk_shader_paintable_get_property;
gobject_class->set_property = gsk_shader_paintable_set_property;
gobject_class->finalize = gsk_shader_paintable_finalize;
properties[PROP_SHADER] =
g_param_spec_object ("shader", "Shader", "The shader",
GSK_TYPE_GL_SHADER,
G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
properties[PROP_ARGS] =
g_param_spec_boxed ("args", "Arguments", "The uniform arguments",
G_TYPE_BYTES,
G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (gobject_class, N_PROPS, properties);
}
static void
gsk_shader_paintable_init (GskShaderPaintable *self)
{
}
/**
* gsk_shader_paintable_new:
* @shader: (transfer full) (nullable): the shader to use
* @data: (transfer full) (nullable): uniform data
*
* Creates a paintable that uses the @shader to create
* pixels. The shader must not require input textures.
* If @data is %NULL, all uniform values are set to zero.
*
* Returns: (transfer full): a new `GskShaderPaintable`
*/
GdkPaintable *
gsk_shader_paintable_new (GskGLShader *shader,
GBytes *data)
{
GdkPaintable *ret;
g_return_val_if_fail (shader == NULL || GSK_IS_GL_SHADER (shader), NULL);
if (shader && !data)
{
int size = gsk_gl_shader_get_args_size (shader);
data = g_bytes_new_take (g_new0 (guchar, size), size);
}
ret = g_object_new (GSK_TYPE_SHADER_PAINTABLE,
"shader", shader,
"args", data,
NULL);
g_clear_object (&shader);
g_clear_pointer (&data, g_bytes_unref);
return ret;
}
/**
* gsk_shader_paintable_set_shader:
* @self: a `GskShaderPaintable`
* @shader: the `GskGLShader` to use
*
* Sets the shader that the paintable will use
* to create pixels. The shader must not require
* input textures.
*/
void
gsk_shader_paintable_set_shader (GskShaderPaintable *self,
GskGLShader *shader)
{
g_return_if_fail (GSK_IS_SHADER_PAINTABLE (self));
g_return_if_fail (shader == NULL || GSK_IS_GL_SHADER (shader));
g_return_if_fail (shader == NULL || gsk_gl_shader_get_n_textures (shader) == 0);
if (!g_set_object (&self->shader, shader))
return;
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SHADER]);
gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
g_clear_pointer (&self->args, g_bytes_unref);
}
/**
* gsk_shader_paintable_get_shader:
* @self: a `GskShaderPaintable`
*
* Returns the shader that the paintable is using.
*
* Returns: (transfer none): the `GskGLShader` that is used
*/
GskGLShader *
gsk_shader_paintable_get_shader (GskShaderPaintable *self)
{
g_return_val_if_fail (GSK_IS_SHADER_PAINTABLE (self), NULL);
return self->shader;
}
/**
* gsk_shader_paintable_set_args:
* @self: a `GskShaderPaintable`
* @data: Data block with uniform data for the shader
*
* Sets the uniform data that will be passed to the
* shader when rendering. The @data will typically
* be produced by a `GskUniformDataBuilder`.
*
* Note that the @data should be considered immutable
* after it has been passed to this function.
*/
void
gsk_shader_paintable_set_args (GskShaderPaintable *self,
GBytes *data)
{
g_return_if_fail (GSK_IS_SHADER_PAINTABLE (self));
g_return_if_fail (data == NULL || g_bytes_get_size (data) == gsk_gl_shader_get_args_size (self->shader));
g_clear_pointer (&self->args, g_bytes_unref);
if (data)
self->args = g_bytes_ref (data);
g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ARGS]);
gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
}
/**
* gsk_shader_paintable_get_args:
* @self: a `GskShaderPaintable`
*
* Returns the uniform data set with
* gsk_shader_paintable_get_args().
*
* Returns: (transfer none): the uniform data
*/
GBytes *
gsk_shader_paintable_get_args (GskShaderPaintable *self)
{
g_return_val_if_fail (GSK_IS_SHADER_PAINTABLE (self), NULL);
return self->args;
}
/**
* gsk_shader_paintable_update_time:
* @self: a `GskShaderPaintable`
* @time_idx: the index of the uniform for time in seconds as float
* @frame_time: the current frame time, as returned by `GdkFrameClock`
*
* This function is a convenience wrapper for
* gsk_shader_paintable_set_args() that leaves all
* uniform values unchanged, except for the uniform with
* index @time_idx, which will be set to the elapsed time
* in seconds, since the first call to this function.
*
* This function is usually called from a `GtkTickCallback`.
*/
void
gsk_shader_paintable_update_time (GskShaderPaintable *self,
int time_idx,
gint64 frame_time)
{
GskShaderArgsBuilder *builder;
GBytes *args;
float time;
if (self->start_time == 0)
self->start_time = frame_time;
time = (frame_time - self->start_time) / (float)G_TIME_SPAN_SECOND;
builder = gsk_shader_args_builder_new (self->shader, self->args);
gsk_shader_args_builder_set_float (builder, time_idx, time);
args = gsk_shader_args_builder_free_to_args (builder);
gsk_shader_paintable_set_args (self, args);
g_bytes_unref (args);
}