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54735dec84
The coding style has for a long time said to avoid using redundant glib
data types such as gint or gchar etc because we feel that they make the
code look unnecessarily foreign to developers coming from outside of the
Gnome developer community.
Note: When we tried to find the historical rationale for the types we
just found that they were apparently only added for consistent syntax
highlighting which didn't seem that compelling.
Up until now we have been continuing to use some of the platform
specific type such as gint{8,16,32,64} and gsize but this patch switches
us over to using the standard c99 equivalents instead so we can further
ensure that our code looks familiar to the widest range of C developers
who might potentially contribute to Cogl.
So instead of using the gint{8,16,32,64} and guint{8,16,32,64} types this
switches all Cogl code to instead use the int{8,16,32,64}_t and
uint{8,16,32,64}_t c99 types instead.
Instead of gsize we now use size_t
For now we are not going to use the c99 _Bool type and instead we have
introduced a new CoglBool type to use instead of gboolean.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 5967dad2400d32ca6319cef6cb572e81bf2c15f0)
223 lines
7.4 KiB
C
223 lines
7.4 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2010 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*
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* Authors:
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* Robert Bragg <robert@linux.intel.com>
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*/
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#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
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#error "Only <cogl/cogl.h> can be included directly."
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#endif
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#ifndef __COGL_ATTRIBUTE_H__
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#define __COGL_ATTRIBUTE_H__
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/* We forward declare the CoglAttribute type here to avoid some circular
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* dependency issues with the following headers.
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*/
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typedef struct _CoglAttribute CoglAttribute;
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#include <cogl/cogl-attribute-buffer.h>
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#include <cogl/cogl-indices.h>
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-attribute
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* @short_description: Functions for declaring and drawing vertex
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* attributes
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*
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* FIXME
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*/
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/**
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* cogl_attribute_new:
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* @attribute_buffer: The #CoglAttributeBuffer containing the actual
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* attribute data
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* @name: The name of the attribute (used to reference it from GLSL)
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* @stride: The number of bytes to jump to get to the next attribute
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* value for the next vertex. (Usually
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* <pre>sizeof (MyVertex)</pre>)
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* @offset: The byte offset from the start of @attribute_buffer for
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* the first attribute value. (Usually
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* <pre>offsetof (MyVertex, component0)</pre>
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* @components: The number of components (e.g. 4 for an rgba color or
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* 3 for and (x,y,z) position)
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* @type: FIXME
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*
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* Describes the layout for a list of vertex attribute values (For
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* example, a list of texture coordinates or colors).
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*
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* The @name is used to access the attribute inside a GLSL vertex
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* shader and there are some special names you should use if they are
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* applicable:
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* <itemizedlist>
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* <listitem>"cogl_position_in" (used for vertex positions)</listitem>
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* <listitem>"cogl_color_in" (used for vertex colors)</listitem>
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* <listitem>"cogl_tex_coord0_in", "cogl_tex_coord1", ...
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* (used for vertex texture coordinates)</listitem>
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* <listitem>"cogl_normal_in" (used for vertex normals)</listitem>
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* </itemizedlist>
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*
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* The attribute values corresponding to different vertices can either
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* be tightly packed or interleaved with other attribute values. For
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* example it's common to define a structure for a single vertex like:
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* |[
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* typedef struct
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* {
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* float x, y, z; /<!-- -->* position attribute *<!-- -->/
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* float s, t; /<!-- -->* texture coordinate attribute *<!-- -->/
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* } MyVertex;
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* ]|
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*
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* And then create an array of vertex data something like:
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* |[
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* MyVertex vertices[100] = { .... }
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* ]|
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*
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* In this case, to describe either the position or texture coordinate
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* attribute you have to move <pre>sizeof (MyVertex)</pre> bytes to
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* move from one vertex to the next. This is called the attribute
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* @stride. If you weren't interleving attributes and you instead had
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* a packed array of float x, y pairs then the attribute stride would
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* be <pre>(2 * sizeof (float))</pre>. So the @stride is the number of
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* bytes to move to find the attribute value of the next vertex.
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*
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* Normally a list of attributes starts at the beginning of an array.
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* So for the <pre>MyVertex</pre> example above the @offset is the
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* offset inside the <pre>MyVertex</pre> structure to the first
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* component of the attribute. For the texture coordinate attribute
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* the offset would be <pre>offsetof (MyVertex, s)</pre> or instead of
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* using the offsetof macro you could use <pre>sizeof (float) * 3</pre>.
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* If you've divided your @array into blocks of non-interleved
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* attributes then you will need to calculate the @offset as the
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* number of bytes in blocks preceding the attribute you're
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* describing.
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*
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* An attribute often has more than one component. For example a color
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* is often comprised of 4 red, green, blue and alpha @components, and a
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* position may be comprised of 2 x and y @components. You should aim
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* to keep the number of components to a minimum as more components
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* means more data needs to be mapped into the GPU which can be a
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* bottlneck when dealing with a large number of vertices.
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*
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* Finally you need to specify the component data type. Here you
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* should aim to use the smallest type that meets your precision
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* requirements. Again the larger the type then more data needs to be
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* mapped into the GPU which can be a bottlneck when dealing with
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* a large number of vertices.
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*
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* Returns: A newly allocated #CoglAttribute describing the
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* layout for a list of attribute values stored in @array.
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*
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* Since: 1.4
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* Stability: Unstable
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*/
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/* XXX: look for a precedent to see if the stride/offset args should
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* have a different order. */
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CoglAttribute *
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cogl_attribute_new (CoglAttributeBuffer *attribute_buffer,
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const char *name,
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size_t stride,
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size_t offset,
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int components,
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CoglAttributeType type);
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/**
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* cogl_attribute_set_normalized:
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* @attribute: A #CoglAttribute
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* @normalized: The new value for the normalized property.
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*
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* Sets whether fixed point attribute types are mapped to the range
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* 0→1. For example when this property is TRUE and a
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* %COGL_ATTRIBUTE_TYPE_UNSIGNED_BYTE type is used then the value 255
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* will be mapped to 1.0.
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*
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* The default value of this property depends on the name of the
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* attribute. For the builtin properties cogl_color_in and
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* cogl_normal_in it will default to TRUE and for all other names it
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* will default to FALSE.
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*
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* Stability: unstable
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* Since: 1.10
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*/
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void
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cogl_attribute_set_normalized (CoglAttribute *attribute,
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CoglBool normalized);
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/**
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* cogl_attribute_get_normalized:
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* @attribute: A #CoglAttribute
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*
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* Return value: the value of the normalized property set with
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* cogl_attribute_set_normalized().
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*
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* Stability: unstable
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* Since: 1.10
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*/
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CoglBool
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cogl_attribute_get_normalized (CoglAttribute *attribute);
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/**
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* cogl_attribute_get_buffer:
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* @attribute: A #CoglAttribute
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*
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* Return value: the #CoglAttributeBuffer that was set with
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* cogl_attribute_set_buffer() or cogl_attribute_new().
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*
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* Stability: unstable
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* Since: 1.10
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*/
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CoglAttributeBuffer *
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cogl_attribute_get_buffer (CoglAttribute *attribute);
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/**
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* cogl_attribute_set_buffer:
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* @attribute: A #CoglAttribute
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* @attribute_buffer: A #CoglAttributeBuffer
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*
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* Sets a new #CoglAttributeBuffer for the attribute.
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*
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* Stability: unstable
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* Since: 1.10
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*/
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void
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cogl_attribute_set_buffer (CoglAttribute *attribute,
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CoglAttributeBuffer *attribute_buffer);
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/**
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* cogl_is_attribute:
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* @object: A #CoglObject
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*
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* Gets whether the given object references a #CoglAttribute.
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*
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* Return value: %TRUE if the @object references a #CoglAttribute,
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* %FALSE otherwise
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*/
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CoglBool
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cogl_is_attribute (void *object);
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G_END_DECLS
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#endif /* __COGL_ATTRIBUTE_H__ */
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