1
0
Fork 0
mutter-performance-source/cogl/cogl-snippet.h
Tomeu Vizoso 93d0de1d9a Mass rename CLUTTER_COMPILATION to COGL_COMPILATION
Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit a99512e5798e48ffa3a9a1a7eb98bc55647ee1b6)
2012-08-06 14:27:45 +01:00

756 lines
26 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 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/>.
*
*
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_SNIPPET_H__
#define __COGL_SNIPPET_H__
#include <glib.h>
G_BEGIN_DECLS
/**
* SECTION:cogl-snippet
* @short_description: Functions for creating and manipulating shader snippets
*
* #CoglSnippet<!-- -->s are used to modify or replace parts of a
* #CoglPipeline using GLSL. GLSL is a programming language supported
* by OpenGL on programmable hardware to provide a more flexible
* description of what should be rendered. A description of GLSL
* itself is outside the scope of this documentation but any good
* OpenGL book should help to describe it.
*
* Unlike in OpenGL, when using GLSL with Cogl it is possible to write
* short snippets to replace small sections of the pipeline instead of
* having to replace the whole of either the vertex or fragment
* pipelines. Of course it is also possible to replace the whole of
* the pipeline if needed.
*
* Each snippet is a standalone chunk of code which would attach to
* the pipeline at a particular point. The code is split into four
* separate strings (all of which are optional):
*
* <glosslist>
* <glossentry>
* <glossterm>declarations</glossterm>
* <glossdef><para>
* The code in this string will be inserted outside of any function in
* the global scope of the shader. This can be used to declare
* uniforms, attributes, varyings and functions to be used by the
* snippet.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>pre</glossterm>
* <glossdef><para>
* The code in this string will be inserted before the hook point.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>post</glossterm>
* <glossdef><para>
* The code in this string will be inserted after the hook point. This
* can be used to modify the results of the builtin generated code for
* that hook point.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>replace</glossterm>
* <glossdef><para>
* If present the code in this string will replace the generated code
* for the hook point.
* </para></glossdef>
* </glossentry>
* </glosslist>
*
* All of the strings apart from the declarations string of a pipeline
* are generated in a single function so they can share variables
* declared from one string in another. The scope of the code is
* limited to each snippet so local variables declared in the snippet
* will not collide with variables declared in another
* snippet. However, code in the 'declarations' string is global to
* the shader so it is the application's responsibility to ensure that
* variables declared here will not collide with those from other
* snippets.
*
* The snippets can be added to a pipeline with
* cogl_pipeline_add_snippet() or
* cogl_pipeline_add_layer_snippet(). Which function to use depends on
* which hook the snippet is targetting. The snippets are all
* generated in the order they are added to the pipeline. That is, the
* post strings are executed in the order they are added to the
* pipeline and the pre strings are executed in reverse order. If any
* replace strings are given for a snippet then any other snippets
* with the same hook added before that snippet will be ignored. The
* different hooks are documented under #CoglSnippetHook.
*
* For portability with GLES2, it is recommended not to use the GLSL
* builtin names such as gl_FragColor. Instead there are replacement
* names under the cogl_* namespace which can be used instead. These
* are:
*
* <glosslist>
* <glossentry>
* <glossterm>uniform mat4
* <emphasis>cogl_modelview_matrix</emphasis></glossterm>
* <glossdef><para>
* The current modelview matrix. This is equivalent to
* #gl_ModelViewMatrix.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>uniform mat4
* <emphasis>cogl_projection_matrix</emphasis></glossterm>
* <glossdef><para>
* The current projection matrix. This is equivalent to
* #gl_ProjectionMatrix.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>uniform mat4
* <emphasis>cogl_modelview_projection_matrix</emphasis></glossterm>
* <glossdef><para>
* The combined modelview and projection matrix. A vertex shader
* would typically use this to transform the incoming vertex
* position. The separate modelview and projection matrices are
* usually only needed for lighting calculations. This is
* equivalent to #gl_ModelViewProjectionMatrix.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>uniform mat4
* <emphasis>cogl_texture_matrix</emphasis>[]</glossterm>
* <glossdef><para>
* An array of matrices for transforming the texture
* coordinates. This is equivalent to #gl_TextureMatrix.
* </para></glossdef>
* </glossentry>
* </glosslist>
*
* In a vertex shader, the following are also available:
*
* <glosslist>
* <glossentry>
* <glossterm>attribute vec4
* <emphasis>cogl_position_in</emphasis></glossterm>
* <glossdef><para>
* The incoming vertex position. This is equivalent to #gl_Vertex.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>attribute vec4
* <emphasis>cogl_color_in</emphasis></glossterm>
* <glossdef><para>
* The incoming vertex color. This is equivalent to #gl_Color.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>attribute vec4
* <emphasis>cogl_tex_coord_in</emphasis></glossterm>
* <glossdef><para>
* The texture coordinate for the first texture unit. This is
* equivalent to #gl_MultiTexCoord0.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>attribute vec4
* <emphasis>cogl_tex_coord0_in</emphasis></glossterm>
* <glossdef><para>
* The texture coordinate for the first texture unit. This is
* equivalent to #gl_MultiTexCoord0. There is also
* #cogl_tex_coord1_in and so on.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>attribute vec3
* <emphasis>cogl_normal_in</emphasis></glossterm>
* <glossdef><para>
* The normal of the vertex. This is equivalent to #gl_Normal.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>vec4
* <emphasis>cogl_position_out</emphasis></glossterm>
* <glossdef><para>
* The calculated position of the vertex. This must be written to
* in all vertex shaders. This is equivalent to #gl_Position.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>float
* <emphasis>cogl_point_size_out</emphasis></glossterm>
* <glossdef><para>
* The calculated size of a point. This is equivalent to #gl_PointSize.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>varying vec4
* <emphasis>cogl_color_out</emphasis></glossterm>
* <glossdef><para>
* The calculated color of a vertex. This is equivalent to #gl_FrontColor.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>varying vec4
* <emphasis>cogl_tex_coord_out</emphasis>[]</glossterm>
* <glossdef><para>
* An array of calculated texture coordinates for a vertex. This is
* equivalent to #gl_TexCoord.
* </para></glossdef>
* </glossentry>
* </glosslist>
*
* In a fragment shader, the following are also available:
*
* <glosslist>
* <glossentry>
* <glossterm>varying vec4 <emphasis>cogl_color_in</emphasis></glossterm>
* <glossdef><para>
* The calculated color of a vertex. This is equivalent to #gl_FrontColor.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>varying vec4
* <emphasis>cogl_tex_coord_in</emphasis>[]</glossterm>
* <glossdef><para>
* An array of calculated texture coordinates for a vertex. This is
* equivalent to #gl_TexCoord.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>vec4 <emphasis>cogl_color_out</emphasis></glossterm>
* <glossdef><para>
* The final calculated color of the fragment. All fragment shaders
* must write to this variable. This is equivalent to
* #gl_FrontColor.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>float <emphasis>cogl_depth_out</emphasis></glossterm>
* <glossdef><para>
* An optional output variable specifying the depth value to use
* for this fragment. This is equivalent to #gl_FragDepth.
* </para></glossdef>
* </glossentry>
* <glossentry>
* <glossterm>bool <emphasis>cogl_front_facing</emphasis></glossterm>
* <glossdef><para>
* A readonly variable that will be true if the current primitive
* is front facing. This can be used to implement two-sided
* coloring algorithms. This is equivalent to #gl_FrontFacing.
* </para></glossdef>
* </glossentry>
* </glosslist>
*
* Here is an example of using a snippet to add a desaturate effect to the
* generated color on a pipeline.
*
* <programlisting>
* CoglPipeline *pipeline = cogl_pipeline_new ();
*
* /<!-- -->* Set up the pipeline here, ie by adding a texture or other
* layers *<!-- -->/
*
* /<!-- -->* Create the snippet. The first string is the declarations which
* we will use to add a uniform. The second is the 'post' string which
* will contain the code to perform the desaturation. *<!-- -->/
* CoglSnippet *snippet =
* cogl_snippet_new (COGL_SNIPPET_HOOK_FRAGMENT,
* "uniform float factor;",
* "float gray = dot (vec3 (0.299, 0.587, 0.114), "
* " cogl_color_out.rgb);"
* "cogl_color_out.rgb = mix (vec3 (gray),"
* " cogl_color_out.rgb,"
* " factor);");
*
* /<!-- -->* Add it to the pipeline *<!-- -->/
* cogl_pipeline_add_snippet (pipeline, snippet);
* /<!-- -->* The pipeline keeps a reference to the snippet
* so we don't need to *<!-- -->/
* cogl_object_unref (snippet);
*
* /<!-- -->* Update the custom uniform on the pipeline *<!-- -->/
* int location = cogl_pipeline_get_uniform_location (pipeline, "factor");
* cogl_pipeline_set_uniform_1f (pipeline, location, 0.5f);
*
* /<!-- -->* Now we can render with the snippet as usual *<!-- -->/
* cogl_push_source (pipeline);
* cogl_rectangle (0, 0, 10, 10);
* cogl_pop_source ();
* </programlisting>
*/
typedef struct _CoglSnippet CoglSnippet;
#define COGL_SNIPPET(OBJECT) ((CoglSnippet *)OBJECT)
/* Enumeration of all the hook points that a snippet can be attached
to within a pipeline. */
/**
* CoglSnippetHook:
* @COGL_SNIPPET_HOOK_VERTEX: A hook for the entire vertex processing
* stage of the pipeline.
* @COGL_SNIPPET_HOOK_VERTEX_TRANSFORM: A hook for the vertex transformation.
* @COGL_SNIPPET_HOOK_FRAGMENT: A hook for the entire fragment
* processing stage of the pipeline.
* @COGL_SNIPPET_HOOK_TEXTURE_COORD_TRANSFORM: A hook for applying the
* layer matrix to a texture coordinate for a layer.
* @COGL_SNIPPET_HOOK_LAYER_FRAGMENT: A hook for the fragment
* processing of a particular layer.
* @COGL_SNIPPET_HOOK_TEXTURE_LOOKUP: A hook for the texture lookup
* stage of a given layer in a pipeline.
*
* #CoglSnippetHook is used to specify a location within a
* #CoglPipeline where the code of the snippet should be used when it
* is attached to a pipeline.
*
* <glosslist>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_VERTEX</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the vertex processing
* stage of the pipeline. This gives a chance for the application to
* modify the vertex attributes generated by the shader. Typically the
* snippet will modify cogl_color_out or cogl_position_out builtins.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted at the top of the
* main() function before any vertex processing is done.
* </para>
* <para>
* The replace string in @snippet will be used instead of the
* generated vertex processing if it is present. This can be used if
* the application wants to provide a complete vertex shader and
* doesn't need the generated output from Cogl.
* </para>
* <para>
* The post string in @snippet will be inserted after all of the
* standard vertex processing is done. This can be used to modify the
* outputs.
* </para>
* </glossdef>
* </glossentry>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_VERTEX_TRANSFORM</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the vertex transform stage.
* Typically the snippet will use the cogl_modelview_matrix,
* cogl_projection_matrix and cogl_modelview_projection_matrix matrices and the
* cogl_position_in attribute. The hook must write to cogl_position_out.
* The default processing for this hook will multiply cogl_position_in by
* the combined modelview-projection matrix and store it on cogl_position_out.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted at the top of the
* main() function before the vertex transform is done.
* </para>
* <para>
* The replace string in @snippet will be used instead of the
* generated vertex transform if it is present.
* </para>
* <para>
* The post string in @snippet will be inserted after all of the
* standard vertex transformation is done. This can be used to modify the
* cogl_position_out in addition to the default processing.
* </para>
* </glossdef>
* </glossentry>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_FRAGMENT</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the fragment processing
* stage of the pipeline. This gives a chance for the application to
* modify the fragment color generated by the shader. Typically the
* snippet will modify cogl_color_out.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted at the top of the
* main() function before any fragment processing is done.
* </para>
* <para>
* The replace string in @snippet will be used instead of the
* generated fragment processing if it is present. This can be used if
* the application wants to provide a complete fragment shader and
* doesn't need the generated output from Cogl.
* </para>
* <para>
* The post string in @snippet will be inserted after all of the
* standard fragment processing is done. At this point the generated
* value for the rest of the pipeline state will already be in
* cogl_color_out so the application can modify the result by altering
* this variable.
* </para>
* </glossdef>
* </glossentry>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_TEXTURE_COORD_TRANSFORM</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the texture coordinate
* transformation of a particular layer. This can be used to replace
* the processing for a layer or to modify the results.
* </para>
* <para>
* Within the snippet code for this hook there are two extra
* variables. The first is a mat4 called cogl_matrix which represents
* the user matrix for this layer. The second is called cogl_tex_coord
* and represents the incoming and outgoing texture coordinate. On
* entry to the hook, cogl_tex_coord contains the value of the
* corresponding texture coordinate attribute for this layer. The hook
* is expected to modify this variable. The output will be passed as a
* varying to the fragment processing stage. The default code will
* just multiply cogl_matrix by cogl_tex_coord and store the result in
* cogl_tex_coord.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted just before the
* fragment processing for this layer. At this point cogl_tex_coord
* still contains the value of the texture coordinate attribute.
* </para>
* <para>
* If a replace string is given then this will be used instead of
* the default fragment processing for this layer. The snippet can
* modify cogl_tex_coord or leave it as is to apply no transformation.
* </para>
* <para>
* The post string in @snippet will be inserted just after the
* transformation. At this point cogl_tex_coord will contain the
* results of the transformation but it can be further modified by the
* snippet.
* </para>
* </glossdef>
* </glossentry>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_LAYER_FRAGMENT</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the fragment processing
* of a particular layer. This can be used to replace the processing
* for a layer or to modify the results.
* </para>
* <para>
* Within the snippet code for this hook there is an extra vec4
* variable called cogl_layer. This contains the resulting color
* that will be used for the layer. This can be modified in the post
* section or it the default processing can be replaced entirely using
* the replace section.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted just before the
* fragment processing for this layer.
* </para>
* <para>
* If a replace string is given then this will be used instead of
* the default fragment processing for this layer. The snippet must write to
* the cogl_layer variable in that case.
* </para>
* <para>
* The post string in @snippet will be inserted just after the
* fragment processing for the layer. The results can be modified by changing
* the value of the cogl_layer variable.
* </para>
* </glossdef>
* </glossentry>
* <glossentry>
* <glossterm>%COGL_SNIPPET_HOOK_TEXTURE_LOOKUP</glossterm>
* <glossdef>
* <para>
* Adds a shader snippet that will hook on to the texture lookup part
* of a given layer. This gives a chance for the application to modify
* the coordinates that will be used for the texture lookup or to
* alter the returned texel.
* </para>
* <para>
* Within the snippet code for this hook there are three extra
* variables available. cogl_sampler is a sampler object
* representing the sampler for the layer where the snippet is
* attached. cogl_tex_coord is a vec4 which contains the texture
* coordinates that will be used for the texture lookup. This can be
* modified. cogl_texel will contain the result of the texture
* lookup. This can also be modified.
* </para>
* <para>
* The declarations string in @snippet will be inserted in the
* global scope of the shader. Use this to declare any uniforms,
* attributes or functions that the snippet requires.
* </para>
* <para>
* The pre string in @snippet will be inserted at the top of the
* main() function before any fragment processing is done. This is a
* good place to modify the cogl_tex_coord variable.
* </para>
* <para>
* If a replace string is given then this will be used instead of a
* the default texture lookup. The snippet would typically use its own
* sampler in this case.
* </para>
* <para>
* The post string in @snippet will be inserted after texture lookup
* has been preformed. Here the snippet can modify the cogl_texel
* variable to alter the returned texel.
* </para>
* </glossdef>
* </glossentry>
* </glosslist>
*
* Since: 1.10
* Stability: Unstable
*/
typedef enum {
/* Per pipeline vertex hooks */
COGL_SNIPPET_HOOK_VERTEX = 0,
COGL_SNIPPET_HOOK_VERTEX_TRANSFORM,
/* Per pipeline fragment hooks */
COGL_SNIPPET_HOOK_FRAGMENT = 2048,
/* Per layer vertex hooks */
COGL_SNIPPET_HOOK_TEXTURE_COORD_TRANSFORM = 4096,
/* Per layer fragment hooks */
COGL_SNIPPET_HOOK_LAYER_FRAGMENT = 6144,
COGL_SNIPPET_HOOK_TEXTURE_LOOKUP
} CoglSnippetHook;
/**
* cogl_snippet_new:
* @hook: The point in the pipeline that this snippet will wrap around
* or replace.
* @declarations: The source code for the declarations for this
* snippet or %NULL. See cogl_snippet_set_declarations().
* @post: The source code to run after the hook point where this
* shader snippet is attached or %NULL. See cogl_snippet_set_post().
*
* Allocates and initializes a new snippet with the given source strings.
*
* Return value: a pointer to a new #CoglSnippet
*
* Since: 1.10
* Stability: Unstable
*/
CoglSnippet *
cogl_snippet_new (CoglSnippetHook hook,
const char *declarations,
const char *post);
/**
* cogl_snippet_get_hook:
* @snippet: A #CoglSnippet
*
* Return value: the hook that was set when cogl_snippet_new() was
* called.
* Since: 1.10
* Stability: Unstable
*/
CoglSnippetHook
cogl_snippet_get_hook (CoglSnippet *snippet);
/**
* cogl_is_snippet:
* @object: A #CoglObject pointer
*
* Gets whether the given @object references an existing snippet object.
*
* Return value: %TRUE if the @object references a #CoglSnippet,
* %FALSE otherwise
*
* Since: 1.10
* Stability: Unstable
*/
CoglBool
cogl_is_snippet (void *object);
/**
* cogl_snippet_set_declarations:
* @snippet: A #CoglSnippet
* @declarations: The new source string for the declarations section
* of this snippet.
*
* Sets a source string that will be inserted in the global scope of
* the generated shader when this snippet is used on a pipeline. This
* string is typically used to declare uniforms, attributes or
* functions that will be used by the other parts of the snippets.
*
* This function should only be called before the snippet is attached
* to its first pipeline. After that the snippet should be considered
* immutable.
*
* Since: 1.10
* Stability: Unstable
*/
void
cogl_snippet_set_declarations (CoglSnippet *snippet,
const char *declarations);
/**
* cogl_snippet_get_declarations:
* @snippet: A #CoglSnippet
*
* Return value: the source string that was set with
* cogl_snippet_set_declarations() or %NULL if none was set.
*
* Since: 1.10
* Stability: Unstable
*/
const char *
cogl_snippet_get_declarations (CoglSnippet *snippet);
/**
* cogl_snippet_set_pre:
* @snippet: A #CoglSnippet
* @pre: The new source string for the pre section of this snippet.
*
* Sets a source string that will be inserted before the hook point in
* the generated shader for the pipeline that this snippet is attached
* to. Please see the documentation of each hook point in
* #CoglPipeline for a description of how this string should be used.
*
* This function should only be called before the snippet is attached
* to its first pipeline. After that the snippet should be considered
* immutable.
*
* Since: 1.10
* Stability: Unstable
*/
void
cogl_snippet_set_pre (CoglSnippet *snippet,
const char *pre);
/**
* cogl_snippet_get_pre:
* @snippet: A #CoglSnippet
*
* Return value: the source string that was set with
* cogl_snippet_set_pre() or %NULL if none was set.
*
* Since: 1.10
* Stability: Unstable
*/
const char *
cogl_snippet_get_pre (CoglSnippet *snippet);
/**
* cogl_snippet_set_replace:
* @snippet: A #CoglSnippet
* @replace: The new source string for the replace section of this snippet.
*
* Sets a source string that will be used instead of any generated
* source code or any previous snippets for this hook point. Please
* see the documentation of each hook point in #CoglPipeline for a
* description of how this string should be used.
*
* This function should only be called before the snippet is attached
* to its first pipeline. After that the snippet should be considered
* immutable.
*
* Since: 1.10
* Stability: Unstable
*/
void
cogl_snippet_set_replace (CoglSnippet *snippet,
const char *replace);
/**
* cogl_snippet_get_replace:
* @snippet: A #CoglSnippet
*
* Return value: the source string that was set with
* cogl_snippet_set_replace() or %NULL if none was set.
*
* Since: 1.10
* Stability: Unstable
*/
const char *
cogl_snippet_get_replace (CoglSnippet *snippet);
/**
* cogl_snippet_set_post:
* @snippet: A #CoglSnippet
* @post: The new source string for the post section of this snippet.
*
* Sets a source string that will be inserted after the hook point in
* the generated shader for the pipeline that this snippet is attached
* to. Please see the documentation of each hook point in
* #CoglPipeline for a description of how this string should be used.
*
* This function should only be called before the snippet is attached
* to its first pipeline. After that the snippet should be considered
* immutable.
*
* Since: 1.10
* Stability: Unstable
*/
void
cogl_snippet_set_post (CoglSnippet *snippet,
const char *post);
/**
* cogl_snippet_get_post:
* @snippet: A #CoglSnippet
*
* Return value: the source string that was set with
* cogl_snippet_set_post() or %NULL if none was set.
*
* Since: 1.10
* Stability: Unstable
*/
const char *
cogl_snippet_get_post (CoglSnippet *snippet);
G_END_DECLS
#endif /* __COGL_SNIPPET_H__ */