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mutter/cogl/cogl-attribute.h
Neil Roberts 6d51a18e7c Add support for per-vertex point sizes 
This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.

There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.

The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.

Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)

Conflicts:
	cogl/cogl-context.c
	cogl/cogl-pipeline-private.h
	cogl/cogl-pipeline.c
	cogl/cogl-private.h
	cogl/driver/gl/cogl-pipeline-progend-fixed.c
	cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
2013-06-07 16:53:29 +01:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* 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/>.
*
*
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_ATTRIBUTE_H__
#define __COGL_ATTRIBUTE_H__
/* We forward declare the CoglAttribute type here to avoid some circular
* dependency issues with the following headers.
*/
typedef struct _CoglAttribute CoglAttribute;
#include <cogl/cogl-attribute-buffer.h>
#include <cogl/cogl-indices.h>
COGL_BEGIN_DECLS
/**
* SECTION:cogl-attribute
* @short_description: Functions for declaring and drawing vertex
* attributes
*
* FIXME
*/
/**
* cogl_attribute_new:
* @attribute_buffer: The #CoglAttributeBuffer containing the actual
* attribute data
* @name: The name of the attribute (used to reference it from GLSL)
* @stride: The number of bytes to jump to get to the next attribute
* value for the next vertex. (Usually
* <literal>sizeof (MyVertex)</literal>)
* @offset: The byte offset from the start of @attribute_buffer for
* the first attribute value. (Usually
* <literal>offsetof (MyVertex, component0)</literal>
* @components: The number of components (e.g. 4 for an rgba color or
* 3 for and (x,y,z) position)
* @type: FIXME
*
* Describes the layout for a list of vertex attribute values (For
* example, a list of texture coordinates or colors).
*
* The @name is used to access the attribute inside a GLSL vertex
* shader and there are some special names you should use if they are
* applicable:
* <itemizedlist>
* <listitem>"cogl_position_in" (used for vertex positions)</listitem>
* <listitem>"cogl_color_in" (used for vertex colors)</listitem>
* <listitem>"cogl_tex_coord0_in", "cogl_tex_coord1", ...
* (used for vertex texture coordinates)</listitem>
* <listitem>"cogl_normal_in" (used for vertex normals)</listitem>
* <listitem>"cogl_point_size_in" (used to set the size of points
* per-vertex. Note this can only be used if
* %COGL_FEATURE_ID_POINT_SIZE_ATTRIBUTE is advertised and
* cogl_pipeline_set_per_vertex_point_size() is called on the pipeline.
* </listitem>
* </itemizedlist>
*
* The attribute values corresponding to different vertices can either
* be tightly packed or interleaved with other attribute values. For
* example it's common to define a structure for a single vertex like:
* |[
* typedef struct
* {
* float x, y, z; /<!-- -->* position attribute *<!-- -->/
* float s, t; /<!-- -->* texture coordinate attribute *<!-- -->/
* } MyVertex;
* ]|
*
* And then create an array of vertex data something like:
* |[
* MyVertex vertices[100] = { .... }
* ]|
*
* In this case, to describe either the position or texture coordinate
* attribute you have to move <literal>sizeof (MyVertex)</literal> bytes to
* move from one vertex to the next. This is called the attribute
* @stride. If you weren't interleving attributes and you instead had
* a packed array of float x, y pairs then the attribute stride would
* be <literal>(2 * sizeof (float))</literal>. So the @stride is the number of
* bytes to move to find the attribute value of the next vertex.
*
* Normally a list of attributes starts at the beginning of an array.
* So for the <literal>MyVertex</literal> example above the @offset is the
* offset inside the <literal>MyVertex</literal> structure to the first
* component of the attribute. For the texture coordinate attribute
* the offset would be <literal>offsetof (MyVertex, s)</literal> or instead of
* using the offsetof macro you could use <literal>sizeof (float) *
* 3</literal>. If you've divided your @array into blocks of non-interleved
* attributes then you will need to calculate the @offset as the number of
* bytes in blocks preceding the attribute you're describing.
*
* An attribute often has more than one component. For example a color
* is often comprised of 4 red, green, blue and alpha @components, and a
* position may be comprised of 2 x and y @components. You should aim
* to keep the number of components to a minimum as more components
* means more data needs to be mapped into the GPU which can be a
* bottlneck when dealing with a large number of vertices.
*
* Finally you need to specify the component data type. Here you
* should aim to use the smallest type that meets your precision
* requirements. Again the larger the type then more data needs to be
* mapped into the GPU which can be a bottlneck when dealing with
* a large number of vertices.
*
* Returns: A newly allocated #CoglAttribute describing the
* layout for a list of attribute values stored in @array.
*
* Since: 1.4
* Stability: Unstable
*/
/* XXX: look for a precedent to see if the stride/offset args should
* have a different order. */
CoglAttribute *
cogl_attribute_new (CoglAttributeBuffer *attribute_buffer,
const char *name,
size_t stride,
size_t offset,
int components,
CoglAttributeType type);
/**
* cogl_attribute_new_const_1f:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @value: The constant value for the attribute
*
* Creates a new, single component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constant @value is a single precision floating point scalar
* which should have a corresponding declaration in GLSL code like:
*
* [|
* attribute float name;
* |]
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant @value.
*/
CoglAttribute *
cogl_attribute_new_const_1f (CoglContext *context,
const char *name,
float value);
/**
* cogl_attribute_new_const_2f:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @constant0: The first component of a 2 component vector
* @constant1: The second component of a 2 component vector
*
* Creates a new, 2 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (@component0, @component1) represent a 2 component
* float vector which should have a corresponding declaration in GLSL
* code like:
*
* [|
* attribute vec2 name;
* |]
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_2f (CoglContext *context,
const char *name,
float component0,
float component1);
/**
* cogl_attribute_new_const_3f:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @constant0: The first component of a 3 component vector
* @constant1: The second component of a 3 component vector
* @constant2: The third component of a 3 component vector
*
* Creates a new, 3 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (@component0, @component1, @component2) represent a 3
* component float vector which should have a corresponding
* declaration in GLSL code like:
*
* [|
* attribute vec3 name;
* |]
*
* unless the built in name "cogl_normal_in" is being used where no
* explicit GLSL declaration need be made.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_3f (CoglContext *context,
const char *name,
float component0,
float component1,
float component2);
/**
* cogl_attribute_new_const_4f:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @constant0: The first component of a 4 component vector
* @constant1: The second component of a 4 component vector
* @constant2: The third component of a 4 component vector
* @constant3: The fourth component of a 4 component vector
*
* Creates a new, 4 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (@component0, @component1, @component2, @constant3)
* represent a 4 component float vector which should have a
* corresponding declaration in GLSL code like:
*
* [|
* attribute vec4 name;
* |]
*
* unless one of the built in names "cogl_color_in",
* "cogl_tex_coord0_in or "cogl_tex_coord1_in" etc is being used where
* no explicit GLSL declaration need be made.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_4f (CoglContext *context,
const char *name,
float component0,
float component1,
float component2,
float component3);
/**
* cogl_attribute_new_const_2fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @value: A pointer to a 2 component float vector
*
* Creates a new, 2 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (value[0], value[1]) represent a 2 component float
* vector which should have a corresponding declaration in GLSL code
* like:
*
* [|
* attribute vec2 name;
* |]
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_2fv (CoglContext *context,
const char *name,
const float *value);
/**
* cogl_attribute_new_const_3fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @value: A pointer to a 3 component float vector
*
* Creates a new, 3 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (value[0], value[1], value[2]) represent a 3
* component float vector which should have a corresponding
* declaration in GLSL code like:
*
* [|
* attribute vec3 name;
* |]
*
* unless the built in name "cogl_normal_in" is being used where no
* explicit GLSL declaration need be made.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_3fv (CoglContext *context,
const char *name,
const float *value);
/**
* cogl_attribute_new_const_4fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @value: A pointer to a 4 component float vector
*
* Creates a new, 4 component, attribute whose value remains
* constant across all the vertices of a primitive without needing to
* duplicate the value for each vertex.
*
* The constants (value[0], value[1], value[2], value[3]) represent a
* 4 component float vector which should have a corresponding
* declaration in GLSL code like:
*
* [|
* attribute vec4 name;
* |]
*
* unless one of the built in names "cogl_color_in",
* "cogl_tex_coord0_in or "cogl_tex_coord1_in" etc is being used where
* no explicit GLSL declaration need be made.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant vector.
*/
CoglAttribute *
cogl_attribute_new_const_4fv (CoglContext *context,
const char *name,
const float *value);
/**
* cogl_attribute_new_const_2x2fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @matrix2x2: A pointer to a 2 by 2 matrix
* @transpose: Whether the matrix should be transposed on upload or
* not
*
* Creates a new matrix attribute whose value remains constant
* across all the vertices of a primitive without needing to duplicate
* the value for each vertex.
*
* @matrix2x2 represent a square 2 by 2 matrix specified in
* column-major order (each pair of consecutive numbers represents a
* column) which should have a corresponding declaration in GLSL code
* like:
*
* [|
* attribute mat2 name;
* |]
*
* If @transpose is %TRUE then all matrix components are rotated
* around the diagonal of the matrix such that the first column
* becomes the first row and the second column becomes the second row.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant matrix.
*/
CoglAttribute *
cogl_attribute_new_const_2x2fv (CoglContext *context,
const char *name,
const float *matrix2x2,
CoglBool transpose);
/**
* cogl_attribute_new_const_3x3fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @matrix3x3: A pointer to a 3 by 3 matrix
* @transpose: Whether the matrix should be transposed on upload or
* not
*
* Creates a new matrix attribute whose value remains constant
* across all the vertices of a primitive without needing to duplicate
* the value for each vertex.
*
* @matrix3x3 represent a square 3 by 3 matrix specified in
* column-major order (each triple of consecutive numbers represents a
* column) which should have a corresponding declaration in GLSL code
* like:
*
* [|
* attribute mat3 name;
* |]
*
* If @transpose is %TRUE then all matrix components are rotated
* around the diagonal of the matrix such that the first column
* becomes the first row and the second column becomes the second row
* etc.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant matrix.
*/
CoglAttribute *
cogl_attribute_new_const_3x3fv (CoglContext *context,
const char *name,
const float *matrix3x3,
CoglBool transpose);
/**
* cogl_attribute_new_const_4x4fv:
* @context: A #CoglContext
* @name: The name of the attribute (used to reference it from GLSL)
* @matrix4x4: A pointer to a 4 by 4 matrix
* @transpose: Whether the matrix should be transposed on upload or
* not
*
* Creates a new matrix attribute whose value remains constant
* across all the vertices of a primitive without needing to duplicate
* the value for each vertex.
*
* @matrix4x4 represent a square 4 by 4 matrix specified in
* column-major order (each 4-tuple of consecutive numbers represents a
* column) which should have a corresponding declaration in GLSL code
* like:
*
* [|
* attribute mat4 name;
* |]
*
* If @transpose is %TRUE then all matrix components are rotated
* around the diagonal of the matrix such that the first column
* becomes the first row and the second column becomes the second row
* etc.
*
* Returns: A newly allocated #CoglAttribute representing the given
* constant matrix.
*/
CoglAttribute *
cogl_attribute_new_const_4x4fv (CoglContext *context,
const char *name,
const float *matrix4x4,
CoglBool transpose);
/**
* cogl_attribute_set_normalized:
* @attribute: A #CoglAttribute
* @normalized: The new value for the normalized property.
*
* Sets whether fixed point attribute types are mapped to the range
* 0→1. For example when this property is TRUE and a
* %COGL_ATTRIBUTE_TYPE_UNSIGNED_BYTE type is used then the value 255
* will be mapped to 1.0.
*
* The default value of this property depends on the name of the
* attribute. For the builtin properties cogl_color_in and
* cogl_normal_in it will default to TRUE and for all other names it
* will default to FALSE.
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_attribute_set_normalized (CoglAttribute *attribute,
CoglBool normalized);
/**
* cogl_attribute_get_normalized:
* @attribute: A #CoglAttribute
*
* Return value: the value of the normalized property set with
* cogl_attribute_set_normalized().
*
* Stability: unstable
* Since: 1.10
*/
CoglBool
cogl_attribute_get_normalized (CoglAttribute *attribute);
/**
* cogl_attribute_get_buffer:
* @attribute: A #CoglAttribute
*
* Return value: the #CoglAttributeBuffer that was set with
* cogl_attribute_set_buffer() or cogl_attribute_new().
*
* Stability: unstable
* Since: 1.10
*/
CoglAttributeBuffer *
cogl_attribute_get_buffer (CoglAttribute *attribute);
/**
* cogl_attribute_set_buffer:
* @attribute: A #CoglAttribute
* @attribute_buffer: A #CoglAttributeBuffer
*
* Sets a new #CoglAttributeBuffer for the attribute.
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_attribute_set_buffer (CoglAttribute *attribute,
CoglAttributeBuffer *attribute_buffer);
/**
* cogl_is_attribute:
* @object: A #CoglObject
*
* Gets whether the given object references a #CoglAttribute.
*
* Return value: %TRUE if the @object references a #CoglAttribute,
* %FALSE otherwise
*/
CoglBool
cogl_is_attribute (void *object);
COGL_END_DECLS
#endif /* __COGL_ATTRIBUTE_H__ */
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