Class
ClutterShaderEffect
Description [src]
class Clutter.ShaderEffect : Clutter.OffscreenEffect
{
/* No available fields */
}Base class for shader effects
ClutterShaderEffect is a class that implements all the plumbing for
creating ClutterEffects using GLSL shaders.
ClutterShaderEffect creates an offscreen buffer and then applies the
GLSL shader (after checking whether the compilation and linking were
successful) to the buffer before painting it on screen.
Implementing a ClutterShaderEffect
Creating a sub-class of ClutterShaderEffect requires the
overriding of the Clutter.OffscreenEffectClass.paint_target virtual
function from the ClutterOffscreenEffect class. It is also convenient
to implement the Clutter.ShaderEffectClass.get_static_shader_source
virtual function in case you are planning to create more than one
instance of the effect.
The Clutter.ShaderEffectClass.get_static_shader_source
function should return a copy of the shader source to use. This
function is only called once per subclass of ClutterShaderEffect
regardless of how many instances of the effect are created. The
source for the shader is typically stored in a static const
string which is returned from this function via g_strdup().
The Clutter.OffscreenEffectClass.paint_target should set the
shader’s uniforms if any. This is done by calling
clutter_shader_effect_set_uniform_value() or
clutter_shader_effect_set_uniform(). The sub-class should then
chain up to the ClutterShaderEffect implementation.
Setting uniforms on a ClutterShaderEffect
The example below shows a typical implementation of the
Clutter.ShaderEffectClass.get_static_shader_source and
Clutter.OffscreenEffectClass.paint_target virtual functions
for a ClutterShaderEffect subclass.
static gchar *
my_effect_get_static_shader_source (ClutterShaderEffect *effect)
{
// shader_source is set elsewhere
return g_strdup (shader_source);
}
static gboolean
my_effect_paint_target (ClutterOffscreenEffect *effect)
{
MyEffect *self = MY_EFFECT (effect);
ClutterShaderEffect *shader = CLUTTER_SHADER_EFFECT (effect);
ClutterEffectClass *parent_class;
gfloat component_r, component_g, component_b;
// the "tex" uniform is declared in the shader as:
//
// uniform int tex;
//
// and it is passed a constant value of 0
clutter_shader_effect_set_uniform (shader, "tex", G_TYPE_INT, 1, 0);
// the "component" uniform is declared in the shader as:
//
// uniform vec3 component;
//
// and it's defined to contain the normalized components
// of a #ClutterColor
component_r = self->color.red / 255.0f;
component_g = self->color.green / 255.0f;
component_b = self->color.blue / 255.0f;
clutter_shader_effect_set_uniform (shader, "component",
G_TYPE_FLOAT, 3,
component_r,
component_g,
component_b);
// chain up to the parent's implementation
parent_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (my_effect_parent_class);
return parent_class->paint_target (effect);
}
Constructors
clutter_shader_effect_new
Creates a new ClutterShaderEffect, to be applied to an actor using
clutter_actor_add_effect().
Instance methods
clutter_shader_effect_set_uniform
Sets a list of values as the payload for the uniform name inside
the shader effect.
clutter_shader_effect_set_uniform_value
Sets value as the payload for the uniform name inside the shader effect.
Methods inherited from ClutterOffscreenEffect (5)
clutter_offscreen_effect_create_texture
Calls the Clutter.OffscreenEffectClass.create_texture virtual function of the effect.
clutter_offscreen_effect_get_pipeline
Retrieves the pipeline used as a render target for the offscreen
buffer created by effect.
clutter_offscreen_effect_get_target_size
Retrieves the size of the offscreen buffer used by effect to
paint the actor to which it has been applied.
clutter_offscreen_effect_get_texture
Retrieves the texture used as a render target for the offscreen
buffer created by effect.
clutter_offscreen_effect_paint_target
Calls the Clutter.OffscreenEffectClass.paint_target virtual function of the effect.
Methods inherited from ClutterEffect (1)
clutter_effect_queue_repaint
Queues a repaint of the effect. The effect can detect when the ‘paint’
method is called as a result of this function because it will not
have the CLUTTER_EFFECT_PAINT_ACTOR_DIRTY flag set. In that case the
effect is free to assume that the actor has not changed its
appearance since the last time it was painted so it doesn’t need to
call clutter_actor_continue_paint() if it can draw a cached
image. This is mostly intended for effects that are using a
%CoglOffscreen to redirect the actor (such as
%ClutterOffscreenEffect). In that case the effect can save a bit of
rendering time by painting the cached texture without causing the
entire actor to be painted.
Methods inherited from ClutterActorMeta (5)
clutter_actor_meta_get_actor
Retrieves a pointer to the ClutterActor that owns meta.
clutter_actor_meta_get_enabled
Retrieves whether meta is enabled.
clutter_actor_meta_get_name
Retrieves the name set using clutter_actor_meta_set_name().
clutter_actor_meta_set_enabled
Sets whether meta should be enabled or not.
clutter_actor_meta_set_name
Sets the name of meta.
Properties
Clutter.ShaderEffect:shader-type
The type of shader that is used by the effect. This property
should be set by the constructor of ClutterShaderEffect
sub-classes.
Properties inherited from ClutterActorMeta (3)
Clutter.ActorMeta:actor
The ClutterActor attached to the ClutterActorMeta instance.
Clutter.ActorMeta:enabled
Whether or not the ClutterActorMeta is enabled.
Clutter.ActorMeta:name
The unique name to access the ClutterActorMeta.
Signals
Signals inherited from GObject (1)
GObject::notify
The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.
Class structure
struct ClutterShaderEffectClass {
gchar* (* get_static_shader_source) (
ClutterShaderEffect* effect
);
}The ClutterShaderEffectClass structure contains
only private data.
Class members
get_static_shader_source: gchar* (* get_static_shader_source) ( ClutterShaderEffect* effect )Returns the GLSL source code to use for instances of this shader effect. Note that this function is only called once per subclass of
ClutterShaderEffectregardless of how many instances are used. It is expected that subclasses will return a copy of a static string from this function.
Virtual methods
Clutter.ShaderEffectClass.get_static_shader_source
Returns the GLSL source code to use for
instances of this shader effect. Note that this function is only
called once per subclass of ClutterShaderEffect regardless of how
many instances are used. It is expected that subclasses will return
a copy of a static string from this function.