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mutter/clutter/clutter-effect.c

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Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
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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-effect
* @short_description: Base class for actor effects
*
* The #ClutterEffect class provides a default type and API for creating
* effects for generic actors.
*
* Effects are a #ClutterActorMeta sub-class that modify the way an actor
* is painted in a way that is not part of the actor's implementation.
*
* Effects should be the preferred way to affect the paint sequence of an
* actor without sub-classing the actor itself and overriding the
* #ClutterActor::paint virtual function.
*
* <refsect2 id="ClutterEffect-implementation">
* <title>Implementing a ClutterEffect</title>
* <para>Creating a sub-class of #ClutterEffect requires the implementation
docs: Fix Effect subclassing section It still mentions the long since removed "prepare" function.
2010-06-10 16:34:48 +00:00
* of two virtual functions:</para>
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
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* <itemizedlist>
* <listitem><simpara><function>pre_paint()</function>, which is called
* before painting the #ClutterActor.</simpara></listitem>
* <listitem><simpara><function>post_paint()</function>, which is called
* after painting the #ClutterActor.</simpara></listitem>
* </itemizedlist>
* <para>The <function>pre_paint()</function> function should be used to set
* up the #ClutterEffect right before the #ClutterActor's paint
docs: Fix Effect subclassing section It still mentions the long since removed "prepare" function.
2010-06-10 16:34:48 +00:00
* sequence. This function can fail, and return %FALSE; in that case, no
* <function>post_paint()</function> invocation will follow.</para>
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
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* <para>The <function>post_paint()</function> function is called after the
* #ClutterActor's paint sequence.</para>
* <para>The <function>pre_paint()</function> phase could be seen as a custom
* handler to the #ClutterActor::paint signal, while the
* <function>post_paint()</function> phase could be seen as a custom handler
* to the #ClutterActor::paint signal connected using
* g_signal_connect_after().</para>
* <example id="ClutterEffect-example">
* <title>A simple ClutterEffect implementation</title>
* <para>The example below creates two rectangles: one will be painted
* "behind" the actor, while another will be painted "on top" of the actor.
docs: Fix Effect subclassing section It still mentions the long since removed "prepare" function.
2010-06-10 16:34:48 +00:00
* The <function>set_actor()</function> implementation will create the two
* materials used for the two different rectangles; the
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
2010-04-08 09:55:15 +00:00
* <function>pre_paint()</function> function will paint the first material
* using cogl_rectangle(), while the <function>post_paint()</function>
* phase will paint the second material.</para>
* <programlisting>
* typedef struct {
* ClutterEffect parent_instance;
*
* CoglHandle rect_1;
* CoglHandle rect_2;
* } MyEffect;
*
* typedef struct _ClutterEffectClass MyEffectClass;
*
* G_DEFINE_TYPE (MyEffect, my_effect, CLUTTER_TYPE_EFFECT);
*
* static void
* my_effect_set_actor (ClutterActorMeta *meta,
* ClutterActor *actor)
* {
* MyEffect *self = MY_EFFECT (meta);
*
* /&ast; Clear the previous state &ast;/
* if (self-&gt;rect_1)
* {
* cogl_handle_unref (self-&gt;rect_1);
* self-&gt;rect_1 = NULL;
* }
*
* if (self-&gt;rect_2)
* {
* cogl_handle_unref (self-&gt;rect_2);
* self-&gt;rect_2 = NULL;
* }
*
* /&ast; Maintain a pointer to the actor &ast;
* self-&gt;actor = actor;
*
* /&ast; If we've been detached by the actor then we should
* &ast; just bail out here
* &ast;/
* if (self-&gt;actor == NULL)
* return;
*
* /&ast; Create a red material &ast;/
* self-&gt;rect_1 = cogl_material_new ();
* cogl_material_set_color4f (self-&gt;rect_1, 1.0, 0.0, 0.0, 1.0);
*
* /&ast; Create a green material &ast;/
* self-&gt;rect_2 = cogl_material_new ();
* cogl_material_set_color4f (self-&gt;rect_2, 0.0, 1.0, 0.0, 1.0);
* }
*
* static gboolean
* my_effect_pre_paint (ClutterEffect *effect)
* {
* MyEffect *self = MY_EFFECT (effect);
* gfloat width, height;
*
* /&ast; If we were disabled we don't need to paint anything &ast;/
* if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
* return FALSE;
*
* clutter_actor_get_size (self-&gt;actor, &amp;width, &amp;height);
*
* /&ast; Paint the first rectangle in the upper left quadrant &ast;/
* cogl_set_source (self-&gt;rect_1);
* cogl_rectangle (0, 0, width / 2, height / 2);
*
* return TRUE;
* }
*
* static void
* my_effect_post_paint (ClutterEffect *effect)
* {
* MyEffect *self = MY_EFFECT (effect);
* gfloat width, height;
*
* clutter_actor_get_size (self-&gt;actor, &amp;width, &amp;height);
*
* /&ast; Paint the second rectangle in the lower right quadrant &ast;/
* cogl_set_source (self-&gt;rect_2);
* cogl_rectangle (width / 2, height / 2, width, height);
* }
*
* static void
* my_effect_class_init (MyEffectClass *klass)
* {
* ClutterActorMetaClas *meta_class = CLUTTER_ACTOR_META_CLASS (klass);
*
* meta_class-&gt;set_actor = my_effect_set_actor;
*
* klass-&gt;pre_paint = my_effect_pre_paint;
* klass-&gt;post_paint = my_effect_post_paint;
* }
* </programlisting>
* </example>
* </refsect2>
*
* #ClutterEffect is available since Clutter 1.4
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-effect.h"
#include "clutter-actor-meta-private.h"
#include "clutter-debug.h"
Move ClutterEffect private symbols to a private header No point in cluttering up clutter-private.h even more than necessary.
2011-02-18 16:00:39 +00:00
#include "clutter-effect-private.h"
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
2010-04-08 09:55:15 +00:00
#include "clutter-enum-types.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
G_DEFINE_ABSTRACT_TYPE (ClutterEffect,
clutter_effect,
CLUTTER_TYPE_ACTOR_META);
static gboolean
clutter_effect_real_pre_paint (ClutterEffect *effect)
{
return TRUE;
}
static void
clutter_effect_real_post_paint (ClutterEffect *effect)
{
}
paint volumes: another pass at the design This is a fairly extensive second pass at exposing paint volumes for actors. The API has changed to allow clutter_actor_get_paint_volume to fail since there are times - such as when an actor isn't a descendent of the stage - when the volume can't be determined. Another example is when something has connected to the "paint" signal of the actor and we simply have no way of knowing what might be drawn in that handler. The API has also be changed to return a const ClutterPaintVolume pointer (transfer none) so we can avoid having to dynamically allocate the volumes in the most common/performance critical code paths. Profiling was showing the slice allocation of volumes taking about 1% of an apps time, for some fairly basic tests. Most volumes can now simply be allocated on the stack; for clutter_actor_get_paint_volume we return a pointer to &priv->paint_volume and if we need a more dynamic allocation there is now a _clutter_stage_paint_volume_stack_allocate() mechanism which lets us allocate data which expires at the start of the next frame. The API has been extended to make it easier to implement get_paint_volume for containers by using clutter_actor_get_transformed_paint_volume and clutter_paint_volume_union. The first allows you to query the paint volume of a child but transformed into parent actor coordinates. The second lets you combine volumes together so you can union all the volumes for a container's children and report that as the container's own volume. The representation of paint volumes has been updated to consider that 2D actors are the most common. The effect apis, clutter-texture and clutter-group have been update accordingly.
2010-09-07 17:04:19 +00:00
static gboolean
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
clutter_effect_real_get_paint_volume (ClutterEffect *effect,
ClutterPaintVolume *volume)
{
paint volumes: another pass at the design This is a fairly extensive second pass at exposing paint volumes for actors. The API has changed to allow clutter_actor_get_paint_volume to fail since there are times - such as when an actor isn't a descendent of the stage - when the volume can't be determined. Another example is when something has connected to the "paint" signal of the actor and we simply have no way of knowing what might be drawn in that handler. The API has also be changed to return a const ClutterPaintVolume pointer (transfer none) so we can avoid having to dynamically allocate the volumes in the most common/performance critical code paths. Profiling was showing the slice allocation of volumes taking about 1% of an apps time, for some fairly basic tests. Most volumes can now simply be allocated on the stack; for clutter_actor_get_paint_volume we return a pointer to &priv->paint_volume and if we need a more dynamic allocation there is now a _clutter_stage_paint_volume_stack_allocate() mechanism which lets us allocate data which expires at the start of the next frame. The API has been extended to make it easier to implement get_paint_volume for containers by using clutter_actor_get_transformed_paint_volume and clutter_paint_volume_union. The first allows you to query the paint volume of a child but transformed into parent actor coordinates. The second lets you combine volumes together so you can union all the volumes for a container's children and report that as the container's own volume. The representation of paint volumes has been updated to consider that 2D actors are the most common. The effect apis, clutter-texture and clutter-group have been update accordingly.
2010-09-07 17:04:19 +00:00
return TRUE;
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
}
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
2010-04-08 09:55:15 +00:00
static void
clutter_effect_class_init (ClutterEffectClass *klass)
{
klass->pre_paint = clutter_effect_real_pre_paint;
klass->post_paint = clutter_effect_real_post_paint;
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
klass->get_paint_volume = clutter_effect_real_get_paint_volume;
Add the ClutterEffect abstract class ClutterEffect is an abstract class that should be used to apply effects on generic actors. The ClutterEffect class just defines what an effect should implement; it could be defined as an interface, but we might want to add some default behavior dependent on the internal state at a later point. The effect API applies to any actor, so we need to provide a way to assign an effect to an actor, and let ClutterActor call the Effect methods during the paint sequence. Once an effect is attached to an actor we will perform the paint in this order: • Effect::pre_paint() • Actor::paint signal emission • Effect::post_paint() Since an effect might collide with the Shader class, we either allow a shader or an effect for the time being.
2010-04-08 09:55:15 +00:00
}
static void
clutter_effect_init (ClutterEffect *self)
{
}
gboolean
_clutter_effect_pre_paint (ClutterEffect *effect)
{
g_return_val_if_fail (CLUTTER_IS_EFFECT (effect), FALSE);
return CLUTTER_EFFECT_GET_CLASS (effect)->pre_paint (effect);
}
void
_clutter_effect_post_paint (ClutterEffect *effect)
{
g_return_if_fail (CLUTTER_IS_EFFECT (effect));
CLUTTER_EFFECT_GET_CLASS (effect)->post_paint (effect);
}
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
paint volumes: another pass at the design This is a fairly extensive second pass at exposing paint volumes for actors. The API has changed to allow clutter_actor_get_paint_volume to fail since there are times - such as when an actor isn't a descendent of the stage - when the volume can't be determined. Another example is when something has connected to the "paint" signal of the actor and we simply have no way of knowing what might be drawn in that handler. The API has also be changed to return a const ClutterPaintVolume pointer (transfer none) so we can avoid having to dynamically allocate the volumes in the most common/performance critical code paths. Profiling was showing the slice allocation of volumes taking about 1% of an apps time, for some fairly basic tests. Most volumes can now simply be allocated on the stack; for clutter_actor_get_paint_volume we return a pointer to &priv->paint_volume and if we need a more dynamic allocation there is now a _clutter_stage_paint_volume_stack_allocate() mechanism which lets us allocate data which expires at the start of the next frame. The API has been extended to make it easier to implement get_paint_volume for containers by using clutter_actor_get_transformed_paint_volume and clutter_paint_volume_union. The first allows you to query the paint volume of a child but transformed into parent actor coordinates. The second lets you combine volumes together so you can union all the volumes for a container's children and report that as the container's own volume. The representation of paint volumes has been updated to consider that 2D actors are the most common. The effect apis, clutter-texture and clutter-group have been update accordingly.
2010-09-07 17:04:19 +00:00
gboolean
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
_clutter_effect_get_paint_volume (ClutterEffect *effect,
ClutterPaintVolume *volume)
{
paint volumes: another pass at the design This is a fairly extensive second pass at exposing paint volumes for actors. The API has changed to allow clutter_actor_get_paint_volume to fail since there are times - such as when an actor isn't a descendent of the stage - when the volume can't be determined. Another example is when something has connected to the "paint" signal of the actor and we simply have no way of knowing what might be drawn in that handler. The API has also be changed to return a const ClutterPaintVolume pointer (transfer none) so we can avoid having to dynamically allocate the volumes in the most common/performance critical code paths. Profiling was showing the slice allocation of volumes taking about 1% of an apps time, for some fairly basic tests. Most volumes can now simply be allocated on the stack; for clutter_actor_get_paint_volume we return a pointer to &priv->paint_volume and if we need a more dynamic allocation there is now a _clutter_stage_paint_volume_stack_allocate() mechanism which lets us allocate data which expires at the start of the next frame. The API has been extended to make it easier to implement get_paint_volume for containers by using clutter_actor_get_transformed_paint_volume and clutter_paint_volume_union. The first allows you to query the paint volume of a child but transformed into parent actor coordinates. The second lets you combine volumes together so you can union all the volumes for a container's children and report that as the container's own volume. The representation of paint volumes has been updated to consider that 2D actors are the most common. The effect apis, clutter-texture and clutter-group have been update accordingly.
2010-09-07 17:04:19 +00:00
g_return_val_if_fail (CLUTTER_IS_EFFECT (effect), FALSE);
g_return_val_if_fail (volume != NULL, FALSE);
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
paint volumes: another pass at the design This is a fairly extensive second pass at exposing paint volumes for actors. The API has changed to allow clutter_actor_get_paint_volume to fail since there are times - such as when an actor isn't a descendent of the stage - when the volume can't be determined. Another example is when something has connected to the "paint" signal of the actor and we simply have no way of knowing what might be drawn in that handler. The API has also be changed to return a const ClutterPaintVolume pointer (transfer none) so we can avoid having to dynamically allocate the volumes in the most common/performance critical code paths. Profiling was showing the slice allocation of volumes taking about 1% of an apps time, for some fairly basic tests. Most volumes can now simply be allocated on the stack; for clutter_actor_get_paint_volume we return a pointer to &priv->paint_volume and if we need a more dynamic allocation there is now a _clutter_stage_paint_volume_stack_allocate() mechanism which lets us allocate data which expires at the start of the next frame. The API has been extended to make it easier to implement get_paint_volume for containers by using clutter_actor_get_transformed_paint_volume and clutter_paint_volume_union. The first allows you to query the paint volume of a child but transformed into parent actor coordinates. The second lets you combine volumes together so you can union all the volumes for a container's children and report that as the container's own volume. The representation of paint volumes has been updated to consider that 2D actors are the most common. The effect apis, clutter-texture and clutter-group have been update accordingly.
2010-09-07 17:04:19 +00:00
return CLUTTER_EFFECT_GET_CLASS (effect)->get_paint_volume (effect, volume);
effect: Allow any effect to override the paint volume An Effect implementation might override the paint volume of the actor to which it is applied to. The get_paint_volume() virtual function should be added to the Effect class vtable so that any effect can get the current paint volume and update it. The clutter_actor_get_paint_volume() function becomes context aware, and does the right thing if called from within a ClutterEffect pre_paint() or post_paint() implementation, by allowing all effects in the chain up to the caller to modify the paint volume.
2010-08-16 16:02:15 +00:00
}
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