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clutter/clutter/clutter-desaturate-effect.c

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2010 Intel Corporation.
*
* 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/>.
*
* Author:
* Emmanuele Bassi <ebassi@linux.intel.com>
*/
/**
* SECTION:clutter-desaturate-effect
* @short_description: A desaturation effect
* @see_also: #ClutterEffect, #ClutterOffscreenEffect
*
* #ClutterDesaturateEffect is a sub-class of #ClutterEffect that
* desaturates the color of an actor and its contents. The strenght
* of the desaturation effect is controllable and animatable through
* the #ClutterDesaturateEffect:factor property.
*
* #ClutterDesaturateEffect is available since Clutter 1.4
*/
#define CLUTTER_DESATURATE_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_DESATURATE_EFFECT, ClutterDesaturateEffectClass))
#define CLUTTER_IS_DESATURATE_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_DESATURATE_EFFECT))
#define CLUTTER_DESATURATE_EFFECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_DESATURATE_EFFECT, ClutterDesaturateEffectClass))
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#define CLUTTER_ENABLE_EXPERIMENTAL_API
#include <math.h>
#include "clutter-desaturate-effect.h"
#include "cogl/cogl.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-offscreen-effect.h"
#include "clutter-private.h"
struct _ClutterDesaturateEffect
{
ClutterOffscreenEffect parent_instance;
/* the desaturation factor, also known as "strength" */
gdouble factor;
gint factor_uniform;
gint tex_width;
gint tex_height;
CoglPipeline *pipeline;
};
struct _ClutterDesaturateEffectClass
{
ClutterOffscreenEffectClass parent_class;
CoglPipeline *base_pipeline;
};
/* the magic gray vec3 has been taken from the NTSC conversion weights
* as defined by:
*
* "OpenGL Superbible, 4th edition"
* -- Richard S. Wright Jr, Benjamin Lipchak, Nicholas Haemel
* Addison-Wesley
*/
static const gchar *desaturate_glsl_declarations =
"uniform float factor;\n"
"\n"
"vec3 desaturate (const vec3 color, const float desaturation)\n"
"{\n"
" const vec3 gray_conv = vec3 (0.299, 0.587, 0.114);\n"
" vec3 gray = vec3 (dot (gray_conv, color));\n"
" return vec3 (mix (color.rgb, gray, desaturation));\n"
"}\n";
static const gchar *desaturate_glsl_source =
" cogl_color_out.rgb = desaturate (cogl_color_out.rgb, factor);\n";
enum
{
PROP_0,
PROP_FACTOR,
PROP_LAST
};
static GParamSpec *obj_props[PROP_LAST];
G_DEFINE_TYPE (ClutterDesaturateEffect,
clutter_desaturate_effect,
CLUTTER_TYPE_OFFSCREEN_EFFECT);
static gboolean
clutter_desaturate_effect_pre_paint (ClutterEffect *effect)
{
ClutterDesaturateEffect *self = CLUTTER_DESATURATE_EFFECT (effect);
ClutterEffectClass *parent_class;
if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
return FALSE;
if (!clutter_feature_available (CLUTTER_FEATURE_SHADERS_GLSL))
{
/* if we don't have support for GLSL shaders then we
* forcibly disable the ActorMeta
*/
g_warning ("Unable to use the ShaderEffect: the graphics hardware "
"or the current GL driver does not implement support "
"for the GLSL shading language.");
clutter_actor_meta_set_enabled (CLUTTER_ACTOR_META (effect), FALSE);
return FALSE;
}
parent_class = CLUTTER_EFFECT_CLASS (clutter_desaturate_effect_parent_class);
if (parent_class->pre_paint (effect))
{
ClutterOffscreenEffect *offscreen_effect =
CLUTTER_OFFSCREEN_EFFECT (effect);
CoglHandle texture;
texture = clutter_offscreen_effect_get_texture (offscreen_effect);
self->tex_width = cogl_texture_get_width (texture);
self->tex_height = cogl_texture_get_height (texture);
cogl_pipeline_set_layer_texture (self->pipeline, 0, texture);
return TRUE;
}
else
return FALSE;
}
static void
clutter_desaturate_effect_paint_target (ClutterOffscreenEffect *effect)
{
ClutterDesaturateEffect *self = CLUTTER_DESATURATE_EFFECT (effect);
ClutterActor *actor;
CoglHandle texture;
guint8 paint_opacity;
texture = clutter_offscreen_effect_get_texture (effect);
cogl_pipeline_set_layer_texture (self->pipeline, 0, texture);
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
paint_opacity = clutter_actor_get_paint_opacity (actor);
cogl_pipeline_set_color4ub (self->pipeline,
paint_opacity,
paint_opacity,
paint_opacity,
paint_opacity);
cogl_push_source (self->pipeline);
cogl_rectangle (0, 0,
cogl_texture_get_width (texture),
cogl_texture_get_height (texture));
cogl_pop_source ();
}
static void
clutter_desaturate_effect_dispose (GObject *gobject)
{
ClutterDesaturateEffect *self = CLUTTER_DESATURATE_EFFECT (gobject);
if (self->pipeline != NULL)
{
cogl_object_unref (self->pipeline);
self->pipeline = NULL;
}
G_OBJECT_CLASS (clutter_desaturate_effect_parent_class)->dispose (gobject);
}
static void
clutter_desaturate_effect_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterDesaturateEffect *effect = CLUTTER_DESATURATE_EFFECT (gobject);
switch (prop_id)
{
case PROP_FACTOR:
clutter_desaturate_effect_set_factor (effect,
g_value_get_double (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_desaturate_effect_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterDesaturateEffect *effect = CLUTTER_DESATURATE_EFFECT (gobject);
switch (prop_id)
{
case PROP_FACTOR:
g_value_set_double (value, effect->factor);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
update_factor_uniform (ClutterDesaturateEffect *self)
{
if (self->factor_uniform > -1)
cogl_pipeline_set_uniform_1f (self->pipeline,
self->factor_uniform,
self->factor);
}
static void
clutter_desaturate_effect_class_init (ClutterDesaturateEffectClass *klass)
{
ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterOffscreenEffectClass *offscreen_class;
offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
offscreen_class->paint_target = clutter_desaturate_effect_paint_target;
effect_class->pre_paint = clutter_desaturate_effect_pre_paint;
/**
* ClutterDesaturateEffect:factor:
*
* The desaturation factor, between 0.0 (no desaturation) and 1.0 (full
* desaturation).
*
* Since: 1.4
*/
obj_props[PROP_FACTOR] =
g_param_spec_double ("factor",
P_("Factor"),
P_("The desaturation factor"),
0.0, 1.0,
1.0,
CLUTTER_PARAM_READWRITE);
gobject_class->dispose = clutter_desaturate_effect_dispose;
gobject_class->set_property = clutter_desaturate_effect_set_property;
gobject_class->get_property = clutter_desaturate_effect_get_property;
g_object_class_install_properties (gobject_class, PROP_LAST, obj_props);
}
static void
clutter_desaturate_effect_init (ClutterDesaturateEffect *self)
{
ClutterDesaturateEffectClass *klass = CLUTTER_DESATURATE_EFFECT_GET_CLASS (self);
if (G_UNLIKELY (klass->base_pipeline == NULL))
{
CoglContext *ctx =
clutter_backend_get_cogl_context (clutter_get_default_backend ());
CoglSnippet *snippet;
klass->base_pipeline = cogl_pipeline_new (ctx);
snippet = cogl_snippet_new (COGL_SNIPPET_HOOK_FRAGMENT,
desaturate_glsl_declarations,
desaturate_glsl_source);
cogl_pipeline_add_snippet (klass->base_pipeline, snippet);
cogl_object_unref (snippet);
cogl_pipeline_set_layer_null_texture (klass->base_pipeline,
0, /* layer number */
COGL_TEXTURE_TYPE_2D);
}
self->pipeline = cogl_pipeline_copy (klass->base_pipeline);
self->factor_uniform =
cogl_pipeline_get_uniform_location (self->pipeline, "factor");
self->factor = 1.0;
update_factor_uniform (self);
}
/**
* clutter_desaturate_effect_new:
* @factor: the desaturation factor, between 0.0 and 1.0
*
* Creates a new #ClutterDesaturateEffect to be used with
* clutter_actor_add_effect()
*
* Return value: the newly created #ClutterDesaturateEffect or %NULL
*
* Since: 1.4
*/
ClutterEffect *
clutter_desaturate_effect_new (gdouble factor)
{
g_return_val_if_fail (factor >= 0.0 && factor <= 1.0, NULL);
return g_object_new (CLUTTER_TYPE_DESATURATE_EFFECT,
"factor", factor,
NULL);
}
/**
* clutter_desaturate_effect_set_factor:
* @effect: a #ClutterDesaturateEffect
* @factor: the desaturation factor, between 0.0 and 1.0
*
* Sets the desaturation factor for @effect, with 0.0 being "do not desaturate"
* and 1.0 being "fully desaturate"
*
* Since: 1.4
*/
void
clutter_desaturate_effect_set_factor (ClutterDesaturateEffect *effect,
gdouble factor)
{
g_return_if_fail (CLUTTER_IS_DESATURATE_EFFECT (effect));
g_return_if_fail (factor >= 0.0 && factor <= 1.0);
if (fabsf (effect->factor - factor) >= 0.00001)
{
effect->factor = factor;
update_factor_uniform (effect);
clutter_effect_queue_repaint (CLUTTER_EFFECT (effect));
g_object_notify_by_pspec (G_OBJECT (effect), obj_props[PROP_FACTOR]);
}
}
/**
* clutter_desaturate_effect_get_factor:
* @effect: a #ClutterDesaturateEffect
*
* Retrieves the desaturation factor of @effect
*
* Return value: the desaturation factor
*
* Since: 1.4
*/
gdouble
clutter_desaturate_effect_get_factor (ClutterDesaturateEffect *effect)
{
g_return_val_if_fail (CLUTTER_IS_DESATURATE_EFFECT (effect), 0.0);
return effect->factor;
}
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