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Clutter Reference Manual | ![]() |
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Top | Description | Object Hierarchy | Properties |
enum ClutterShaderType; struct ClutterShaderEffect; struct ClutterShaderEffectClass; void clutter_shader_effect_set_uniform (ClutterShaderEffect *effect
,const gchar *name
,GType gtype
,gsize n_values
,...
); void clutter_shader_effect_set_uniform_value (ClutterShaderEffect *effect
,const gchar *name
,const GValue *value
); gboolean clutter_shader_effect_set_shader_source (ClutterShaderEffect *effect
,const gchar *source
); CoglHandle clutter_shader_effect_get_program (ClutterShaderEffect *effect
); CoglHandle clutter_shader_effect_get_shader (ClutterShaderEffect *effect
);
GObject +----GInitiallyUnowned +----ClutterActorMeta +----ClutterEffect +----ClutterOffscreenEffect +----ClutterShaderEffect
ClutterShaderEffect is an abstract 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 successfull) to the buffer before painting it on screen.
Creating a sub-class of ClutterShaderEffect requires the
overriding of the
virtual function
from the ClutterEffect class.pre_paint()
The
should set the shader's
source and eventually set the uniforms. The sub-class should call
pre_paint()
clutter_shader_effect_set_shader_source()
to set the shader source
code, and clutter_shader_effect_set_uniform_value()
or
clutter_shader_effect_set_uniform()
to set the values of the shader
uniforms, if any; the sub-class should then chain up to the
ClutterShaderEffect implementation.
Example 6. Setting uniforms on a ClutterShaderEffect
The example below shows a typical implementation of the
phase of a ClutterShaderEffect
sub-class.pre_paint()
static gboolean my_effect_pre_paint (ClutterEffect *effect) { MyEffect *self = MY_EFFECT (effect); ClutterShaderEffect *shader = CLUTTER_SHADER_EFFECT (effect); ClutterEffectClass *parent_class; gfloat component_r, component_g, component_b; /* if the effect is not enabled we can bail out now */ if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect))) return FALSE; /* this function is a no-op after the first call */ clutter_shader_effect_set_shader_source (shader, shader_source); /* 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_EFFECT_CLASS (my_effect_parent_class); return parent_class->pre_paint (effect); }
ClutterShaderEffect is available since Clutter 1.4
typedef enum { CLUTTER_VERTEX_SHADER, CLUTTER_FRAGMENT_SHADER } ClutterShaderType;
The type of GLSL shader program
Since 1.4
struct ClutterShaderEffect;
The ClutterShaderEffect structure contains only private data and should be accessed using the provided API
Since 1.4
struct ClutterShaderEffectClass { };
The ClutterShaderEffectClass structure contains only private data
Since 1.4
void clutter_shader_effect_set_uniform (ClutterShaderEffect *effect
,const gchar *name
,GType gtype
,gsize n_values
,...
);
Sets a list of values as the payload for the uniform name
inside
the shader effect
The gtype
must be one of: G_TYPE_INT
, for 1 or more integer values;
G_TYPE_FLOAT
, for 1 or more floating point values;
CLUTTER_TYPE_SHADER_INT
, for a pointer to an array of integer values;
CLUTTER_TYPE_SHADER_FLOAT
, for a pointer to an array of floating point
values; and CLUTTER_TYPE_SHADER_MATRIX
, for a pointer to an array of
floating point values mapping a matrix
The number of values interepreted is defined by the n_value
argument, and by the gtype
argument. For instance, a uniform named
"sampler0" and containing a single integer value is set using:
1 2 3 |
clutter_shader_effect_set_uniform (effect, "sampler0", G_TYPE_INT, 1, 0); |
While a uniform named "components" and containing a 3-elements vector of floating point values (a "vec3") can be set using:
1 2 3 4 5 6 7 |
gfloat component_r, component_g, component_b; clutter_shader_effect_set_uniform (effect, "components", G_TYPE_FLOAT, 3, component_r, component_g, component_b); |
or can be set using:
1 2 3 4 5 |
gfloat component_vec[3]; clutter_shader_effect_set_uniform (effect, "components", CLUTTER_TYPE_SHADER_FLOAT, 3, component_vec); |
Finally, a uniform named "map" and containing a matrix can be set using:
1 2 3 |
clutter_shader_effect_set_uniform (effect, "map", CLUTTER_TYPE_SHADER_MATRIX, 1, cogl_matrix_get_array (&matrix)); |
|
a ClutterShaderEffect |
|
the name of the uniform to set |
|
the type of the uniform to set |
|
the number of values |
|
a list of values |
Since 1.4
void clutter_shader_effect_set_uniform_value (ClutterShaderEffect *effect
,const gchar *name
,const GValue *value
);
Sets value
as the payload for the uniform name
inside the shader
effect
The GType of the value
must be one of: G_TYPE_INT
, for a single
integer value; G_TYPE_FLOAT
, for a single floating point value;
CLUTTER_TYPE_SHADER_INT
, for an array of integer values;
CLUTTER_TYPE_SHADER_FLOAT
, for an array of floating point values;
and CLUTTER_TYPE_SHADER_MATRIX
, for a matrix of floating point
values
|
a ClutterShaderEffect |
|
the name of the uniform to set |
|
a GValue with the value of the uniform to set |
Since 1.4
gboolean clutter_shader_effect_set_shader_source (ClutterShaderEffect *effect
,const gchar *source
);
Sets the source of the GLSL shader used by effect
This function should only be called by implementations of the ClutterShaderEffect class, and not by application code.
This function can only be called once; subsequent calls will yield no result.
|
a ClutterShaderEffect |
|
the source of a GLSL shader |
Returns : |
TRUE if the source was set
|
Since 1.4
CoglHandle clutter_shader_effect_get_program (ClutterShaderEffect *effect
);
Retrieves a pointer to the program's handle
|
a ClutterShaderEffect |
Returns : |
a pointer to the program's handle,
or COGL_INVALID_HANDLE . [transfer none]
|
Since 1.4
CoglHandle clutter_shader_effect_get_shader (ClutterShaderEffect *effect
);
Retrieves a pointer to the shader's handle
|
a ClutterShaderEffect |
Returns : |
a pointer to the shader's handle,
or COGL_INVALID_HANDLE . [transfer none]
|
Since 1.4
"shader-type"
property"shader-type" ClutterShaderType : Write / Construct Only
The type of shader that is used by the effect. This property should be set by the constructor of ClutterShaderEffect sub-classes.
Default value: CLUTTER_FRAGMENT_SHADER
Since 1.4