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mutter/clutter/clutter-blur-effect.c
Robert Bragg f3bffe5cab blur-effect: fix paint volume padding 
For the blur effect we use a BLUR_PADDING constant to pad out the volume
of the source actor on the x and y axis. Previously we were offsetting
the origin negatively using BLUR_PADDING and then adding BLUR_PADDING
to the width and height, but we should have been adding 2*BLUR_PADDING
instead.
2010-09-29 15:12:57 +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-blur-effect
* @short_description: A blur effect
* @see_also: #ClutterEffect, #ClutterOffscreenEffect
*
* #ClutterBlurEffect is a sub-class of #ClutterEffect that allows blurring a
* actor and its contents.
*
* #ClutterBlurEffect is available since Clutter 1.4
*/
#define CLUTTER_BLUR_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_BLUR_EFFECT, ClutterBlurEffectClass))
#define CLUTTER_IS_BLUR_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_BLUR_EFFECT))
#define CLUTTER_BLUR_EFFECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_BLUR_EFFECT, ClutterBlurEffectClass))
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-blur-effect.h"
#include "cogl/cogl.h"
#include "clutter-debug.h"
#include "clutter-offscreen-effect.h"
#include "clutter-private.h"
#define BLUR_PADDING 2
typedef struct _ClutterBlurEffectClass ClutterBlurEffectClass;
/* FIXME - lame shader; we should really have a decoupled
* horizontal/vertical two pass shader for the gaussian blur
*/
static const gchar *box_blur_glsl_shader =
"#version 110\n"
"uniform sampler2D tex;\n"
"uniform float x_step, y_step;\n"
"\n"
"vec4 get_rgba_rel (sampler2D source, float dx, float dy)\n"
"{\n"
" return texture2D (tex, gl_TexCoord[0].st + vec2 (dx, dy) * 2.0);\n"
"}\n"
"\n"
"void main ()\n"
"{\n"
" vec4 color = gl_Color * texture2D (tex, vec2 (gl_TexCoord[0].xy));\n"
" color += get_rgba_rel (tex, -x_step, -y_step);\n"
" color += get_rgba_rel (tex, 0.0, -y_step);\n"
" color += get_rgba_rel (tex, x_step, -y_step);\n"
" color += get_rgba_rel (tex, -x_step, 0.0);\n"
" color += get_rgba_rel (tex, 0.0, 0.0);\n"
" color += get_rgba_rel (tex, x_step, 0.0);\n"
" color += get_rgba_rel (tex, -x_step, y_step);\n"
" color += get_rgba_rel (tex, 0.0, y_step);\n"
" color += get_rgba_rel (tex, x_step, y_step);\n"
" gl_FragColor = color / 9.0;\n"
"}";
struct _ClutterBlurEffect
{
ClutterOffscreenEffect parent_instance;
/* a back pointer to our actor, so that we can query it */
ClutterActor *actor;
/* the parameters; x_step and y_step depend on
* the actor's allocation
*/
gfloat x_step;
gfloat y_step;
CoglHandle shader;
CoglHandle program;
gint tex_uniform;
gint x_step_uniform;
gint y_step_uniform;
guint is_compiled : 1;
};
struct _ClutterBlurEffectClass
{
ClutterOffscreenEffectClass parent_class;
};
G_DEFINE_TYPE (ClutterBlurEffect,
clutter_blur_effect,
CLUTTER_TYPE_OFFSCREEN_EFFECT);
static int
next_p2 (int a)
{
int rval = 1;
while (rval < a)
rval <<= 1;
return rval;
}
static gboolean
clutter_blur_effect_pre_paint (ClutterEffect *effect)
{
ClutterBlurEffect *self = CLUTTER_BLUR_EFFECT (effect);
ClutterEffectClass *parent_class;
ClutterActorBox allocation;
gfloat width, height;
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;
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;
}
clutter_actor_get_allocation_box (self->actor, &allocation);
clutter_actor_box_get_size (&allocation, &width, &height);
self->x_step = 1.0f / (float) next_p2 (width);
self->y_step = 1.0f / (float) next_p2 (height);
if (self->shader == COGL_INVALID_HANDLE)
{
self->shader = cogl_create_shader (COGL_SHADER_TYPE_FRAGMENT);
cogl_shader_source (self->shader, box_blur_glsl_shader);
self->is_compiled = FALSE;
self->tex_uniform = -1;
self->x_step_uniform = -1;
self->y_step_uniform = -1;
}
if (self->program == COGL_INVALID_HANDLE)
self->program = cogl_create_program ();
if (!self->is_compiled)
{
g_assert (self->shader != COGL_INVALID_HANDLE);
g_assert (self->program != COGL_INVALID_HANDLE);
cogl_shader_compile (self->shader);
if (!cogl_shader_is_compiled (self->shader))
{
gchar *log_buf = cogl_shader_get_info_log (self->shader);
g_warning (G_STRLOC ": Unable to compile the box blur shader: %s",
log_buf);
g_free (log_buf);
cogl_handle_unref (self->shader);
cogl_handle_unref (self->program);
self->shader = COGL_INVALID_HANDLE;
self->program = COGL_INVALID_HANDLE;
}
else
{
cogl_program_attach_shader (self->program, self->shader);
cogl_program_link (self->program);
cogl_handle_unref (self->shader);
self->is_compiled = TRUE;
self->tex_uniform =
cogl_program_get_uniform_location (self->program, "tex");
self->x_step_uniform =
cogl_program_get_uniform_location (self->program, "x_step");
self->y_step_uniform =
cogl_program_get_uniform_location (self->program, "y_step");
}
}
parent_class = CLUTTER_EFFECT_CLASS (clutter_blur_effect_parent_class);
return parent_class->pre_paint (effect);
}
static CoglHandle
clutter_blur_effect_create_texture (ClutterOffscreenEffect *effect,
gfloat min_width,
gfloat min_height)
{
return cogl_texture_new_with_size (min_width + (2 * BLUR_PADDING),
min_height + (2 * BLUR_PADDING),
COGL_TEXTURE_NO_SLICING,
COGL_PIXEL_FORMAT_RGBA_8888_PRE);
}
static void
clutter_blur_effect_paint_target (ClutterOffscreenEffect *effect)
{
ClutterBlurEffect *self = CLUTTER_BLUR_EFFECT (effect);
ClutterOffscreenEffectClass *parent;
CoglHandle material;
if (self->program == COGL_INVALID_HANDLE)
goto out;
if (self->tex_uniform > -1)
cogl_program_set_uniform_1i (self->program, self->tex_uniform, 0);
if (self->x_step_uniform > -1)
cogl_program_set_uniform_1f (self->program,
self->x_step_uniform,
self->x_step);
if (self->y_step_uniform > -1)
cogl_program_set_uniform_1f (self->program,
self->y_step_uniform,
self->y_step);
material = clutter_offscreen_effect_get_target (effect);
cogl_material_set_user_program (material, self->program);
out:
parent = CLUTTER_OFFSCREEN_EFFECT_CLASS (clutter_blur_effect_parent_class);
parent->paint_target (effect);
}
static gboolean
clutter_blur_effect_get_paint_volume (ClutterEffect *effect,
ClutterPaintVolume *volume)
{
gfloat cur_width, cur_height;
ClutterVertex origin;
clutter_paint_volume_get_origin (volume, &origin);
cur_width = clutter_paint_volume_get_width (volume);
cur_height = clutter_paint_volume_get_height (volume);
origin.x -= BLUR_PADDING;
origin.y -= BLUR_PADDING;
cur_width += 2 * BLUR_PADDING;
cur_height += 2 * BLUR_PADDING;
clutter_paint_volume_set_origin (volume, &origin);
clutter_paint_volume_set_width (volume, cur_width);
clutter_paint_volume_set_height (volume, cur_height);
return TRUE;
}
static void
clutter_blur_effect_dispose (GObject *gobject)
{
ClutterBlurEffect *self = CLUTTER_BLUR_EFFECT (gobject);
if (self->program != COGL_INVALID_HANDLE)
{
cogl_handle_unref (self->program);
self->program = COGL_INVALID_HANDLE;
self->shader = COGL_INVALID_HANDLE;
}
G_OBJECT_CLASS (clutter_blur_effect_parent_class)->dispose (gobject);
}
static void
clutter_blur_effect_class_init (ClutterBlurEffectClass *klass)
{
ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterOffscreenEffectClass *offscreen_class;
gobject_class->dispose = clutter_blur_effect_dispose;
effect_class->pre_paint = clutter_blur_effect_pre_paint;
effect_class->get_paint_volume = clutter_blur_effect_get_paint_volume;
offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
offscreen_class->create_texture = clutter_blur_effect_create_texture;
offscreen_class->paint_target = clutter_blur_effect_paint_target;
}
static void
clutter_blur_effect_init (ClutterBlurEffect *self)
{
}
/**
* clutter_blur_effect_new:
*
* Creates a new #ClutterBlurEffect to be used with
* clutter_actor_add_effect()
*
* Return value: the newly created #ClutterBlurEffect or %NULL
*
* Since: 1.4
*/
ClutterEffect *
clutter_blur_effect_new (void)
{
return g_object_new (CLUTTER_TYPE_BLUR_EFFECT, NULL);
}
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