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mutter/clutter/clutter-offscreen-effect.h

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effect: Add OffscreenEffect The OffscreenEffect class is meant to be used to implement Effect sub-classes that create an offscreen framebuffer and redirect the actor's paint sequence there. The OffscreenEffect is useful for effects using fragment shaders. Any shader-based effect being applied to an actor through an offscreen buffer should be used before painting the resulting target material and not for every actor. This means that doing: pre_paint: cogl_program_use(program) set up offscreen buffer paint: [ actors ] → offscreen buffer → target material post_paint: paint target material cogl_program_use(null) Is not correct. Unfortunately, we cannot really do: post_paint: cogl_program_use(program) paint target material cogl_program_use(null) Because the OffscreenEffect::post_paint() implementation also pops the offscreen buffer and re-instates the previous framebuffer: post_paint: cogl_program_use(program) change frame buffer ← ouch! paint target material cogl_program_use(null) One way to fix it is to allow using the shader right before painting the target material - which means adding a new virtual inside the OffscreenEffect class vtable in additions to the ones defined by the parent Effect class. The newly-added paint_target() virtual allows the correct sequence of actions by adding an entry point for sub-classes to wrap the "paint target material" operation with custom code, in order to implement the case above correctly as: post_paint: change frame buffer cogl_program_use(program) paint target material cogl_program_use(null) The added upside is that sub-classes of OffscreenEffect involving shaders really just need to override the prepare() and paint_target() virtuals, since the pre_paint() and post_paint() do all that's needed.
2010-05-17 10:39:27 +00:00
/*
* 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>
*/
#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <clutter/clutter.h> can be included directly."
#endif
#ifndef __CLUTTER_OFFSCREEN_EFFECT_H__
#define __CLUTTER_OFFSCREEN_EFFECT_H__
#include <clutter/clutter-effect.h>
G_BEGIN_DECLS
#define CLUTTER_TYPE_OFFSCREEN_EFFECT (clutter_offscreen_effect_get_type ())
#define CLUTTER_OFFSCREEN_EFFECT(o) (G_TYPE_CHECK_INSTANCE_CAST ((o), CLUTTER_TYPE_OFFSCREEN_EFFECT, ClutterOffscreenEffect))
#define CLUTTER_IS_OFFSCREEN_EFFECT(o) (G_TYPE_CHECK_INSTANCE_TYPE ((o), CLUTTER_TYPE_OFFSCREEN_EFFECT))
#define CLUTTER_OFFSCREEN_EFFECT_CLASS(k) (G_TYPE_CHECK_CLASS_CAST ((k), CLUTTER_TYPE_OFFSCREEN_EFFECT, ClutterOffscreenEffectClass))
#define CLUTTER_IS_OFFSCREEN_EFFECT_CLASS(k) (G_TYPE_CHECK_CLASS_TYPE ((k), CLUTTER_TYPE_OFFSCREEN_EFFECT))
#define CLUTTER_OFFSCREEN_EFFECT_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), CLUTTER_TYPE_OFFSCREEN_EFFECT, ClutterOffscreenEffectClass))
typedef struct _ClutterOffscreenEffect ClutterOffscreenEffect;
typedef struct _ClutterOffscreenEffectPrivate ClutterOffscreenEffectPrivate;
typedef struct _ClutterOffscreenEffectClass ClutterOffscreenEffectClass;
/**
* ClutterOffscreenEffect:
*
* The #ClutterOffscreenEffect structure contains only private data
* and should be accessed using the provided API
*
* Since: 1.4
*/
struct _ClutterOffscreenEffect
{
/*< private >*/
ClutterEffect parent_instance;
ClutterOffscreenEffectPrivate *priv;
};
/**
* ClutterOffscreenEffectClass:
offscreen-effect: Rename create_target to create_buffer *** This is an API change *** The create_target() virtual function should return a CoglHandle to a texture; clutter_offscreen_effect_get_target(), instead, returns a CoglMaterial to be painted in the implementation of the paint_target() virtual function. Instead of equating textures with materials, and confusing the user of the API, we should mark the difference more prominently. First of all, we should return a CoglMaterial* (now that we have that as a public type) in get_target(); having handles all over the place does not make it easier to distinguish the semantics of the virtual functions. Then we should rename create_target() to create_texture(), to make it clear that what should be returned is a texture that is used as the backing for the offscreen framebuffer.
2010-09-01 16:56:15 +00:00
* @create_texture: virtual function
effect: Add OffscreenEffect The OffscreenEffect class is meant to be used to implement Effect sub-classes that create an offscreen framebuffer and redirect the actor's paint sequence there. The OffscreenEffect is useful for effects using fragment shaders. Any shader-based effect being applied to an actor through an offscreen buffer should be used before painting the resulting target material and not for every actor. This means that doing: pre_paint: cogl_program_use(program) set up offscreen buffer paint: [ actors ] → offscreen buffer → target material post_paint: paint target material cogl_program_use(null) Is not correct. Unfortunately, we cannot really do: post_paint: cogl_program_use(program) paint target material cogl_program_use(null) Because the OffscreenEffect::post_paint() implementation also pops the offscreen buffer and re-instates the previous framebuffer: post_paint: cogl_program_use(program) change frame buffer ← ouch! paint target material cogl_program_use(null) One way to fix it is to allow using the shader right before painting the target material - which means adding a new virtual inside the OffscreenEffect class vtable in additions to the ones defined by the parent Effect class. The newly-added paint_target() virtual allows the correct sequence of actions by adding an entry point for sub-classes to wrap the "paint target material" operation with custom code, in order to implement the case above correctly as: post_paint: change frame buffer cogl_program_use(program) paint target material cogl_program_use(null) The added upside is that sub-classes of OffscreenEffect involving shaders really just need to override the prepare() and paint_target() virtuals, since the pre_paint() and post_paint() do all that's needed.
2010-05-17 10:39:27 +00:00
* @paint_target: virtual function
*
* The #ClutterOffscreenEffectClass structure contains only private data
*
* Since: 1.4
*/
struct _ClutterOffscreenEffectClass
{
/*< private >*/
ClutterEffectClass parent_class;
/*< public >*/
offscreen-effect: Rename create_target to create_buffer *** This is an API change *** The create_target() virtual function should return a CoglHandle to a texture; clutter_offscreen_effect_get_target(), instead, returns a CoglMaterial to be painted in the implementation of the paint_target() virtual function. Instead of equating textures with materials, and confusing the user of the API, we should mark the difference more prominently. First of all, we should return a CoglMaterial* (now that we have that as a public type) in get_target(); having handles all over the place does not make it easier to distinguish the semantics of the virtual functions. Then we should rename create_target() to create_texture(), to make it clear that what should be returned is a texture that is used as the backing for the offscreen framebuffer.
2010-09-01 16:56:15 +00:00
CoglHandle (* create_texture) (ClutterOffscreenEffect *effect,
effect: Rework the OffscreenEffect painting The OffscreenEffect should set up the off screen draw buffer so that it has the same projection and modelview as if it where on screen; we achieve that by setting up the viewport to be the same size of the stage but with an initial offset given by the left-most vertex of the actor. When we paint the texture attached to the FBO we then set up the modelview matrix of the on screen draw buffer so that it's the same as the stage one: this way, the texture will be painted in screen coordinates and it will occupy the same area as the actor would have had.
2010-04-16 11:33:20 +00:00
gfloat min_width,
gfloat min_height);
void (* paint_target) (ClutterOffscreenEffect *effect);
effect: Add OffscreenEffect The OffscreenEffect class is meant to be used to implement Effect sub-classes that create an offscreen framebuffer and redirect the actor's paint sequence there. The OffscreenEffect is useful for effects using fragment shaders. Any shader-based effect being applied to an actor through an offscreen buffer should be used before painting the resulting target material and not for every actor. This means that doing: pre_paint: cogl_program_use(program) set up offscreen buffer paint: [ actors ] → offscreen buffer → target material post_paint: paint target material cogl_program_use(null) Is not correct. Unfortunately, we cannot really do: post_paint: cogl_program_use(program) paint target material cogl_program_use(null) Because the OffscreenEffect::post_paint() implementation also pops the offscreen buffer and re-instates the previous framebuffer: post_paint: cogl_program_use(program) change frame buffer ← ouch! paint target material cogl_program_use(null) One way to fix it is to allow using the shader right before painting the target material - which means adding a new virtual inside the OffscreenEffect class vtable in additions to the ones defined by the parent Effect class. The newly-added paint_target() virtual allows the correct sequence of actions by adding an entry point for sub-classes to wrap the "paint target material" operation with custom code, in order to implement the case above correctly as: post_paint: change frame buffer cogl_program_use(program) paint target material cogl_program_use(null) The added upside is that sub-classes of OffscreenEffect involving shaders really just need to override the prepare() and paint_target() virtuals, since the pre_paint() and post_paint() do all that's needed.
2010-05-17 10:39:27 +00:00
/*< private >*/
void (* _clutter_offscreen1) (void);
void (* _clutter_offscreen2) (void);
void (* _clutter_offscreen3) (void);
void (* _clutter_offscreen4) (void);
void (* _clutter_offscreen5) (void);
void (* _clutter_offscreen6) (void);
void (* _clutter_offscreen7) (void);
};
GType clutter_offscreen_effect_get_type (void) G_GNUC_CONST;
offscreen-effect: Rename create_target to create_buffer *** This is an API change *** The create_target() virtual function should return a CoglHandle to a texture; clutter_offscreen_effect_get_target(), instead, returns a CoglMaterial to be painted in the implementation of the paint_target() virtual function. Instead of equating textures with materials, and confusing the user of the API, we should mark the difference more prominently. First of all, we should return a CoglMaterial* (now that we have that as a public type) in get_target(); having handles all over the place does not make it easier to distinguish the semantics of the virtual functions. Then we should rename create_target() to create_texture(), to make it clear that what should be returned is a texture that is used as the backing for the offscreen framebuffer.
2010-09-01 16:56:15 +00:00
CoglMaterial *clutter_offscreen_effect_get_target (ClutterOffscreenEffect *effect);
effect: Rework the OffscreenEffect painting The OffscreenEffect should set up the off screen draw buffer so that it has the same projection and modelview as if it where on screen; we achieve that by setting up the viewport to be the same size of the stage but with an initial offset given by the left-most vertex of the actor. When we paint the texture attached to the FBO we then set up the modelview matrix of the on screen draw buffer so that it's the same as the stage one: this way, the texture will be painted in screen coordinates and it will occupy the same area as the actor would have had.
2010-04-16 11:33:20 +00:00
offscreen-effect: Rename create_target to create_buffer *** This is an API change *** The create_target() virtual function should return a CoglHandle to a texture; clutter_offscreen_effect_get_target(), instead, returns a CoglMaterial to be painted in the implementation of the paint_target() virtual function. Instead of equating textures with materials, and confusing the user of the API, we should mark the difference more prominently. First of all, we should return a CoglMaterial* (now that we have that as a public type) in get_target(); having handles all over the place does not make it easier to distinguish the semantics of the virtual functions. Then we should rename create_target() to create_texture(), to make it clear that what should be returned is a texture that is used as the backing for the offscreen framebuffer.
2010-09-01 16:56:15 +00:00
void clutter_offscreen_effect_paint_target (ClutterOffscreenEffect *effect);
CoglHandle clutter_offscreen_effect_create_texture (ClutterOffscreenEffect *effect,
gfloat width,
gfloat height);
effect: Add OffscreenEffect The OffscreenEffect class is meant to be used to implement Effect sub-classes that create an offscreen framebuffer and redirect the actor's paint sequence there. The OffscreenEffect is useful for effects using fragment shaders. Any shader-based effect being applied to an actor through an offscreen buffer should be used before painting the resulting target material and not for every actor. This means that doing: pre_paint: cogl_program_use(program) set up offscreen buffer paint: [ actors ] → offscreen buffer → target material post_paint: paint target material cogl_program_use(null) Is not correct. Unfortunately, we cannot really do: post_paint: cogl_program_use(program) paint target material cogl_program_use(null) Because the OffscreenEffect::post_paint() implementation also pops the offscreen buffer and re-instates the previous framebuffer: post_paint: cogl_program_use(program) change frame buffer ← ouch! paint target material cogl_program_use(null) One way to fix it is to allow using the shader right before painting the target material - which means adding a new virtual inside the OffscreenEffect class vtable in additions to the ones defined by the parent Effect class. The newly-added paint_target() virtual allows the correct sequence of actions by adding an entry point for sub-classes to wrap the "paint target material" operation with custom code, in order to implement the case above correctly as: post_paint: change frame buffer cogl_program_use(program) paint target material cogl_program_use(null) The added upside is that sub-classes of OffscreenEffect involving shaders really just need to override the prepare() and paint_target() virtuals, since the pre_paint() and post_paint() do all that's needed.
2010-05-17 10:39:27 +00:00
G_END_DECLS
#endif /* __CLUTTER_OFFSCREEN_EFFECT_H__ */
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