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Cogl 2.0 Reference Manual | ![]() |
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Top | Description |
CoglPipeline * cogl_pipeline_new (void
); CoglPipeline * cogl_pipeline_copy (CoglPipeline *source
); gboolean cogl_is_pipeline (CoglHandle handle
); void cogl_pipeline_set_color (CoglPipeline *pipeline
,const CoglColor *color
); void cogl_pipeline_set_color4ub (CoglPipeline *pipeline
,guint8 red
,guint8 green
,guint8 blue
,guint8 alpha
); void cogl_pipeline_set_color4f (CoglPipeline *pipeline
,float red
,float green
,float blue
,float alpha
); void cogl_pipeline_get_color (CoglPipeline *pipeline
,CoglColor *color
); void cogl_pipeline_set_ambient (CoglPipeline *pipeline
,const CoglColor *ambient
); void cogl_pipeline_get_ambient (CoglPipeline *pipeline
,CoglColor *ambient
); void cogl_pipeline_set_diffuse (CoglPipeline *pipeline
,const CoglColor *diffuse
); void cogl_pipeline_get_diffuse (CoglPipeline *pipeline
,CoglColor *diffuse
); void cogl_pipeline_set_ambient_and_diffuse (CoglPipeline *pipeline
,const CoglColor *color
); void cogl_pipeline_set_emission (CoglPipeline *pipeline
,const CoglColor *emission
); void cogl_pipeline_get_emission (CoglPipeline *pipeline
,CoglColor *emission
); void cogl_pipeline_set_specular (CoglPipeline *pipeline
,const CoglColor *specular
); void cogl_pipeline_get_specular (CoglPipeline *pipeline
,CoglColor *specular
); void cogl_pipeline_set_shininess (CoglPipeline *pipeline
,float shininess
); float cogl_pipeline_get_shininess (CoglPipeline *pipeline
); void cogl_pipeline_set_alpha_test_function (CoglPipeline *pipeline
,CoglPipelineAlphaFunc alpha_func
,float alpha_reference
); #define COGL_BLEND_STRING_ERROR enum CoglBlendStringError; gboolean cogl_pipeline_set_blend (CoglPipeline *pipeline
,const char *blend_string
,GError **error
); void cogl_pipeline_set_blend_constant (CoglPipeline *pipeline
,const CoglColor *constant_color
); void cogl_pipeline_set_point_size (CoglHandle pipeline
,float point_size
); float cogl_pipeline_get_point_size (CoglHandle pipeline
); void cogl_pipeline_set_layer_texture (CoglPipeline *pipeline
,int layer_index
,CoglHandle texture
); void cogl_pipeline_set_layer_filters (CoglPipeline *pipeline
,int layer_index
,CoglPipelineFilter min_filter
,CoglPipelineFilter mag_filter
); void cogl_pipeline_set_layer_wrap_mode (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
); void cogl_pipeline_set_layer_wrap_mode_s (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
); void cogl_pipeline_set_layer_wrap_mode_t (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
); void cogl_pipeline_set_layer_wrap_mode_p (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
); gboolean cogl_pipeline_set_layer_combine (CoglPipeline *pipeline
,int layer_index
,const char *blend_string
,GError **error
); void cogl_pipeline_set_layer_combine_constant (CoglPipeline *pipeline
,int layer_index
,const CoglColor *constant
); void cogl_pipeline_set_layer_matrix (CoglPipeline *pipeline
,int layer_index
,const CoglMatrix *matrix
); gboolean cogl_pipeline_set_layer_point_sprite_coords_enabled (CoglPipeline *pipeline
,int layer_index
,gboolean enable
,GError **error
); gboolean cogl_pipeline_get_layer_point_sprite_coords_enabled (CoglPipeline *pipeline
,int layer_index
); void cogl_pipeline_remove_layer (CoglPipeline *pipeline
,int layer_index
); int cogl_pipeline_get_n_layers (CoglPipeline *pipeline
); void cogl_pipeline_foreach_layer (CoglPipeline *pipeline
,CoglPipelineLayerCallback callback
,void *user_data
);
Cogl allows creating and manipulating objects representing the full configuration of the GPU pipeline. In simplified terms the GPU pipeline takes primitive geometry as the input, it first performs vertex processing, allowing you to deform your geometry, then rasterizes that (turning it from pure geometry into fragments) then performs fragment processing including depth testing and texture mapping. Finally it blends the result with the framebuffer.
CoglPipeline * cogl_pipeline_new (void
);
Allocates and initializes a default simple pipeline that will color a primitive white.
Returns : |
a pointer to a new CoglPipeline |
CoglPipeline * cogl_pipeline_copy (CoglPipeline *source
);
Creates a new pipeline with the configuration copied from the source pipeline.
We would strongly advise developers to always aim to use
cogl_pipeline_copy()
instead of cogl_pipeline_new()
whenever there will
be any similarity between two pipelines. Copying a pipeline helps Cogl
keep track of a pipelines ancestry which we may use to help minimize GPU
state changes.
|
a CoglPipeline object to copy |
Returns : |
a pointer to the newly allocated CoglPipeline |
Since 2.0
gboolean cogl_is_pipeline (CoglHandle handle
);
Gets whether the given handle references an existing pipeline object.
|
A CoglHandle |
Returns : |
TRUE if the handle references a CoglPipeline,
FALSE otherwise
|
void cogl_pipeline_set_color (CoglPipeline *pipeline
,const CoglColor *color
);
Sets the basic color of the pipeline, used when no lighting is enabled.
Note that if you don't add any layers to the pipeline then the color
will be blended unmodified with the destination; the default blend
expects premultiplied colors: for example, use (0.5, 0.0, 0.0, 0.5) for
semi-transparent red. See cogl_color_premultiply()
.
The default value is (1.0, 1.0, 1.0, 1.0)
|
A CoglPipeline object |
|
The components of the color |
Since 2.0
void cogl_pipeline_set_color4ub (CoglPipeline *pipeline
,guint8 red
,guint8 green
,guint8 blue
,guint8 alpha
);
Sets the basic color of the pipeline, used when no lighting is enabled.
The default value is (0xff, 0xff, 0xff, 0xff)
|
A CoglPipeline object |
|
The red component |
|
The green component |
|
The blue component |
|
The alpha component |
Since 2.0
void cogl_pipeline_set_color4f (CoglPipeline *pipeline
,float red
,float green
,float blue
,float alpha
);
Sets the basic color of the pipeline, used when no lighting is enabled.
The default value is (1.0, 1.0, 1.0, 1.0)
|
A CoglPipeline object |
|
The red component |
|
The green component |
|
The blue component |
|
The alpha component |
Since 2.0
void cogl_pipeline_get_color (CoglPipeline *pipeline
,CoglColor *color
);
Retrieves the current pipeline color.
|
A CoglPipeline object |
|
The location to store the color. [out] |
Since 2.0
void cogl_pipeline_set_ambient (CoglPipeline *pipeline
,const CoglColor *ambient
);
Sets the pipeline's ambient color, in the standard OpenGL lighting model. The ambient color affects the overall color of the object.
Since the diffuse color will be intense when the light hits the surface directly, the ambient will be most apparent where the light hits at a slant.
The default value is (0.2, 0.2, 0.2, 1.0)
|
A CoglPipeline object |
|
The components of the desired ambient color |
Since 2.0
void cogl_pipeline_get_ambient (CoglPipeline *pipeline
,CoglColor *ambient
);
Retrieves the current ambient color for pipeline
|
A CoglPipeline object |
|
The location to store the ambient color |
Since 2.0
void cogl_pipeline_set_diffuse (CoglPipeline *pipeline
,const CoglColor *diffuse
);
Sets the pipeline's diffuse color, in the standard OpenGL lighting model. The diffuse color is most intense where the light hits the surface directly - perpendicular to the surface.
The default value is (0.8, 0.8, 0.8, 1.0)
|
A CoglPipeline object |
|
The components of the desired diffuse color |
Since 2.0
void cogl_pipeline_get_diffuse (CoglPipeline *pipeline
,CoglColor *diffuse
);
Retrieves the current diffuse color for pipeline
|
A CoglPipeline object |
|
The location to store the diffuse color |
Since 2.0
void cogl_pipeline_set_ambient_and_diffuse (CoglPipeline *pipeline
,const CoglColor *color
);
Conveniently sets the diffuse and ambient color of pipeline
at the same
time. See cogl_pipeline_set_ambient()
and cogl_pipeline_set_diffuse()
.
The default ambient color is (0.2, 0.2, 0.2, 1.0)
The default diffuse color is (0.8, 0.8, 0.8, 1.0)
|
A CoglPipeline object |
|
The components of the desired ambient and diffuse colors |
Since 2.0
void cogl_pipeline_set_emission (CoglPipeline *pipeline
,const CoglColor *emission
);
Sets the pipeline's emissive color, in the standard OpenGL lighting model. It will look like the surface is a light source emitting this color.
The default value is (0.0, 0.0, 0.0, 1.0)
|
A CoglPipeline object |
|
The components of the desired emissive color |
Since 2.0
void cogl_pipeline_get_emission (CoglPipeline *pipeline
,CoglColor *emission
);
Retrieves the pipelines current emission color.
|
A CoglPipeline object |
|
The location to store the emission color |
Since 2.0
void cogl_pipeline_set_specular (CoglPipeline *pipeline
,const CoglColor *specular
);
Sets the pipeline's specular color, in the standard OpenGL lighting model. The intensity of the specular color depends on the viewport position, and is brightest along the lines of reflection.
The default value is (0.0, 0.0, 0.0, 1.0)
|
A CoglPipeline object |
|
The components of the desired specular color |
Since 2.0
void cogl_pipeline_get_specular (CoglPipeline *pipeline
,CoglColor *specular
);
Retrieves the pipelines current specular color.
|
A CoglPipeline object |
|
The location to store the specular color |
Since 2.0
void cogl_pipeline_set_shininess (CoglPipeline *pipeline
,float shininess
);
Sets the shininess of the pipeline, in the standard OpenGL lighting
model, which determines the size of the specular highlights. A
higher shininess
will produce smaller highlights which makes the
object appear more shiny.
The default value is 0.0
|
A CoglPipeline object |
|
The desired shininess; must be >= 0.0 |
Since 2.0
float cogl_pipeline_get_shininess (CoglPipeline *pipeline
);
Retrieves the pipelines current emission color.
|
A CoglPipeline object |
Returns : |
The pipelines current shininess value |
Since 2.0
void cogl_pipeline_set_alpha_test_function (CoglPipeline *pipeline
,CoglPipelineAlphaFunc alpha_func
,float alpha_reference
);
Before a primitive is blended with the framebuffer, it goes through an alpha test stage which lets you discard fragments based on the current alpha value. This function lets you change the function used to evaluate the alpha channel, and thus determine which fragments are discarded and which continue on to the blending stage.
The default is COGL_PIPELINE_ALPHA_FUNC_ALWAYS
|
A CoglPipeline object |
|
A CoglPipelineAlphaFunc constant
|
|
A reference point that the chosen alpha function uses to compare incoming fragments to. |
Since 2.0
#define COGL_BLEND_STRING_ERROR (cogl_blend_string_error_quark ())
GError domain for blend string parser errors
Since 1.0
typedef enum { /*< prefix=COGL_BLEND_STRING_ERROR >*/ COGL_BLEND_STRING_ERROR_PARSE_ERROR, COGL_BLEND_STRING_ERROR_ARGUMENT_PARSE_ERROR, COGL_BLEND_STRING_ERROR_INVALID_ERROR, COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR } CoglBlendStringError;
Error enumeration for the blend strings parser
Generic parse error | |
Argument parse error | |
Internal parser error | |
Blend string not supported by the GPU |
Since 1.0
gboolean cogl_pipeline_set_blend (CoglPipeline *pipeline
,const char *blend_string
,GError **error
);
If not already familiar; please refer here for an overview of what blend strings are, and their syntax.
Blending occurs after the alpha test function, and combines fragments with the framebuffer.
Currently the only blend function Cogl exposes is ADD()
. So any valid
blend statements will be of the form:
1 |
<channel-mask>=ADD(SRC_COLOR*(<factor>), DST_COLOR*(<factor>)) |
This is the list of source-names usable as blend factors:
SRC_COLOR: The color of the in comming fragment
DST_COLOR: The color of the framebuffer
CONSTANT: The constant set via cogl_pipeline_set_blend_constant()
The source names can be used according to the color-source and factor syntax, so for example "(1-SRC_COLOR[A])" would be a valid factor, as would "(CONSTANT[RGB])"
These can also be used as factors:
Example 1. Blend Strings/1
Blend a non-premultiplied source over a destination with premultiplied alpha:
"RGB = ADD(SRC_COLOR*(SRC_COLOR[A]), DST_COLOR*(1-SRC_COLOR[A]))" "A = ADD(SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
Example 2. Blend Strings/2
Blend a premultiplied source over a destination with premultiplied alpha
"RGBA = ADD(SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
The default blend string is:
1 |
RGBA = ADD (SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A])) |
That gives normal alpha-blending when the calculated color for the pipeline is in premultiplied form.
|
A CoglPipeline object |
|
A Cogl blend string describing the desired blend function. |
|
return location for a GError that may report lack of driver
support if you give separate blend string statements for the alpha
channel and RGB channels since some drivers, or backends such as
GLES 1.1, don't support this feature. May be NULL , in which case a
warning will be printed out using GLib's logging facilities if an
error is encountered.
|
Returns : |
TRUE if the blend string was successfully parsed, and the
described blending is supported by the underlying driver/hardware. If
there was an error, FALSE is returned and error is set accordingly (if
present).
|
Since 2.0
void cogl_pipeline_set_blend_constant (CoglPipeline *pipeline
,const CoglColor *constant_color
);
When blending is setup to reference a CONSTANT blend factor then blending will depend on the constant set with this function.
|
A CoglPipeline object |
|
The constant color you want |
Since 2.0
void cogl_pipeline_set_point_size (CoglHandle pipeline
,float point_size
);
Changes the size of points drawn when COGL_VERTICES_MODE_POINTS
is
used with the vertex buffer API. Note that typically the GPU will
only support a limited minimum and maximum range of point sizes. If
the chosen point size is outside that range then the nearest value
within that range will be used instead. The size of a point is in
screen space so it will be the same regardless of any
transformations. The default point size is 1.0.
|
a CoglHandle to a pipeline. |
|
the new point size. |
Since 2.0
float cogl_pipeline_get_point_size (CoglHandle pipeline
);
Get the size of points drawn when COGL_VERTICES_MODE_POINTS
is
used with the vertex buffer API.
|
a CoglHandle to a pipeline. |
Returns : |
the point size of the pipeline. |
Since 2.0
void cogl_pipeline_set_layer_texture (CoglPipeline *pipeline
,int layer_index
,CoglHandle texture
);
void cogl_pipeline_set_layer_filters (CoglPipeline *pipeline
,int layer_index
,CoglPipelineFilter min_filter
,CoglPipelineFilter mag_filter
);
Changes the decimation and interpolation filters used when a texture is drawn at other scales than 100%.
|
A CoglPipeline object |
|
the layer number to change. |
|
the filter used when scaling a texture down. |
|
the filter used when magnifying a texture. |
void cogl_pipeline_set_layer_wrap_mode (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
);
Sets the wrap mode for all three coordinates of texture lookups on
this layer. This is equivalent to calling
cogl_pipeline_set_layer_wrap_mode_s()
,
cogl_pipeline_set_layer_wrap_mode_t()
and
cogl_pipeline_set_layer_wrap_mode_p()
separately.
|
A CoglPipeline object |
|
the layer number to change. |
|
the new wrap mode |
Since 2.0
void cogl_pipeline_set_layer_wrap_mode_s (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
);
Sets the wrap mode for the 's' coordinate of texture lookups on this layer.
|
A CoglPipeline object |
|
the layer number to change. |
|
the new wrap mode |
Since 2.0
void cogl_pipeline_set_layer_wrap_mode_t (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
);
Sets the wrap mode for the 't' coordinate of texture lookups on this layer.
|
A CoglPipeline object |
|
the layer number to change. |
|
the new wrap mode |
Since 2.0
void cogl_pipeline_set_layer_wrap_mode_p (CoglPipeline *pipeline
,int layer_index
,CoglPipelineWrapMode mode
);
Sets the wrap mode for the 'p' coordinate of texture lookups on this layer. 'p' is the third coordinate.
|
A CoglPipeline object |
|
the layer number to change. |
|
the new wrap mode |
Since 2.0
gboolean cogl_pipeline_set_layer_combine (CoglPipeline *pipeline
,int layer_index
,const char *blend_string
,GError **error
);
If not already familiar; you can refer here for an overview of what blend strings are and there syntax.
These are all the functions available for texture combining:
DOT3_RGB(arg0, arg1) = 4 x ((arg0[R] - 0.5)) * (arg1[R] - 0.5) + (arg0[G] - 0.5)) * (arg1[G] - 0.5) + (arg0[B] - 0.5)) * (arg1[B] - 0.5))
DOT3_RGBA(arg0, arg1) = 4 x ((arg0[R] - 0.5)) * (arg1[R] - 0.5) + (arg0[G] - 0.5)) * (arg1[G] - 0.5) + (arg0[B] - 0.5)) * (arg1[B] - 0.5))
Refer to the color-source syntax for describing the arguments. The valid source names for texture combining are:
TEXTURE |
Use the color from the current texture layer |
TEXTURE_0, TEXTURE_1, etc |
Use the color from the specified texture layer |
CONSTANT |
Use the color from the constant given with
cogl_pipeline_set_layer_constant()
|
PRIMARY |
Use the color of the pipeline as set with
cogl_pipeline_set_color()
|
PREVIOUS |
Either use the texture color from the previous layer, or
if this is layer 0, use the color of the pipeline as set with
cogl_pipeline_set_color()
|
This is effectively what the default blending is:
1 |
RGBA = MODULATE (PREVIOUS, TEXTURE) |
This could be used to cross-fade between two images, using the alpha component of a constant as the interpolator. The constant color is given by calling cogl_pipeline_set_layer_constant.
1 |
RGBA = INTERPOLATE (PREVIOUS, TEXTURE, CONSTANT[A]) |
|
A CoglPipeline object |
|
Specifies the layer you want define a combine function for |
|
A Cogl blend string describing the desired texture combine function. |
|
A GError that may report parse errors or lack of GPU/driver
support. May be NULL , in which case a warning will be printed out if an
error is encountered.
|
Returns : |
TRUE if the blend string was successfully parsed, and the
described texture combining is supported by the underlying driver and
or hardware. On failure, FALSE is returned and error is set
|
Since 2.0
void cogl_pipeline_set_layer_combine_constant (CoglPipeline *pipeline
,int layer_index
,const CoglColor *constant
);
When you are using the 'CONSTANT' color source in a layer combine description then you can use this function to define its value.
|
A CoglPipeline object |
|
Specifies the layer you want to specify a constant used for texture combining |
|
The constant color you want |
Since 2.0
void cogl_pipeline_set_layer_matrix (CoglPipeline *pipeline
,int layer_index
,const CoglMatrix *matrix
);
This function lets you set a matrix that can be used to e.g. translate and rotate a single layer of a pipeline used to fill your geometry.
|
A CoglPipeline object |
|
the index for the layer inside pipeline
|
|
the transformation matrix for the layer |
gboolean cogl_pipeline_set_layer_point_sprite_coords_enabled (CoglPipeline *pipeline
,int layer_index
,gboolean enable
,GError **error
);
When rendering points, if enable
is TRUE
then the texture
coordinates for this layer will be replaced with coordinates that
vary from 0.0 to 1.0 across the primitive. The top left of the
point will have the coordinates 0.0,0.0 and the bottom right will
have 1.0,1.0. If enable
is FALSE
then the coordinates will be
fixed for the entire point.
This function will only work if COGL_FEATURE_POINT_SPRITE
is
available. If the feature is not available then the function will
return FALSE
and set error
.
|
a CoglHandle to a pipeline. |
|
the layer number to change. |
|
whether to enable point sprite coord generation. |
|
A return location for a GError, or NULL to ignore errors. |
Returns : |
TRUE if the function succeeds, FALSE otherwise.
|
Since 2.0
gboolean cogl_pipeline_get_layer_point_sprite_coords_enabled (CoglPipeline *pipeline
,int layer_index
);
Gets whether point sprite coordinate generation is enabled for this texture layer.
|
a CoglHandle to a pipeline. |
|
the layer number to check. |
Returns : |
whether the texture coordinates will be replaced with point sprite coordinates. |
Since 2.0
void cogl_pipeline_remove_layer (CoglPipeline *pipeline
,int layer_index
);
This function removes a layer from your pipeline
|
A CoglPipeline object |
|
Specifies the layer you want to remove |
int cogl_pipeline_get_n_layers (CoglPipeline *pipeline
);
Retrieves the number of layers defined for the given pipeline
|
A CoglPipeline object |
Returns : |
the number of layers |
Since 2.0
void cogl_pipeline_foreach_layer (CoglPipeline *pipeline
,CoglPipelineLayerCallback callback
,void *user_data
);
Iterates all the layer indices of the given pipeline
.
|
A CoglPipeline object |
|
A CoglPipelineLayerCallback to be called for each layer index |
|
Private data that will be passed to the callback |
Since 2.0
Stability Level: Unstable