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mutter/clutter/clutter-desaturate-effect.c
Emmanuele Bassi 23084b9768 docs: Effects fixes for the API reference
2010-06-03 14:34:41 +01:00

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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 uses the programmable pipeline of the GPU
* so it is only available on graphics hardware that supports this
* feature.
*
* #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
#include "clutter-desaturate-effect.h"
#include "cogl/cogl.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-private.h"
#include "clutter-shader-effect.h"
typedef struct _ClutterDesaturateEffectClass ClutterDesaturateEffectClass;
struct _ClutterDesaturateEffect
{
ClutterShaderEffect parent_instance;
/* a back pointer to our actor, so that we can query it */
ClutterActor *actor;
/* the desaturation factor, also known as "strength" */
gdouble factor;
};
struct _ClutterDesaturateEffectClass
{
ClutterShaderEffectClass parent_class;
};
/* 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_shader =
"uniform sampler2D tex;\n"
"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"
"\n"
"void main ()\n"
"{\n"
" vec4 color = gl_Color * texture2D (tex, vec2 (gl_TexCoord[0].xy));\n"
" color.rgb = desaturate (color.rgb, factor);\n"
" gl_FragColor = color;\n"
"}\n";
enum
{
PROP_0,
PROP_FACTOR
};
G_DEFINE_TYPE (ClutterDesaturateEffect,
clutter_desaturate_effect,
CLUTTER_TYPE_SHADER_EFFECT);
static gboolean
clutter_desaturate_effect_pre_paint (ClutterEffect *effect)
{
ClutterDesaturateEffect *self = CLUTTER_DESATURATE_EFFECT (effect);
ClutterShaderEffect *shader_effect;
ClutterEffectClass *parent_class;
float factor;
if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
return FALSE;
self->actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
if (self->actor == NULL)
return FALSE;
shader_effect = CLUTTER_SHADER_EFFECT (effect);
clutter_shader_effect_set_shader_source (shader_effect, desaturate_glsl_shader);
factor = (float) self->factor;
/* bind the uniforms to the factor property */
clutter_shader_effect_set_uniform (shader_effect,
"tex",
G_TYPE_INT, 1,
0);
clutter_shader_effect_set_uniform (shader_effect,
"factor",
G_TYPE_FLOAT, 1,
factor);
parent_class = CLUTTER_EFFECT_CLASS (clutter_desaturate_effect_parent_class);
return parent_class->pre_paint (effect);
}
static void
clutter_desaturate_effect_finalize (GObject *gobject)
{
G_OBJECT_CLASS (clutter_desaturate_effect_parent_class)->finalize (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
clutter_desaturate_effect_class_init (ClutterDesaturateEffectClass *klass)
{
ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
GParamSpec *pspec;
effect_class->pre_paint = clutter_desaturate_effect_pre_paint;
gobject_class->set_property = clutter_desaturate_effect_set_property;
gobject_class->get_property = clutter_desaturate_effect_get_property;
gobject_class->finalize = clutter_desaturate_effect_finalize;
/**
* ClutterDesaturateEffect:factor:
*
* The desaturation factor, between 0.0 (no desaturation) and 1.0 (full
* desaturation).
*
* Since: 1.4
*/
pspec = g_param_spec_double ("factor",
"Factor",
"The desaturation factor",
0.0, 1.0,
1.0,
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_FACTOR, pspec);
}
static void
clutter_desaturate_effect_init (ClutterDesaturateEffect *self)
{
self->factor = 1.0;
}
/**
* 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;
if (effect->actor != NULL)
clutter_actor_queue_redraw (effect->actor);
g_object_notify (G_OBJECT (effect), "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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