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92c3063014
This adds cogl_framebuffer_ apis for drawing attributes and primitives that replace corresponding apis that depend on the default CoglContext. This is part of the on going effort to adapt the Cogl api so it no longer depends on a global context variable. All the new drawing functions also take an explicit pipeline argument since we are also aiming to avoid being a stateful api like Cairo and OpenGL. Being stateless makes it easier for orthogonal components to share access to the GPU. Being stateless should also minimize any impedance miss-match for those wanting to build higher level stateless apis on top of Cogl. Note: none of the legacy, global state options such as cogl_set_depth_test_enabled(), cogl_set_backface_culling_enabled() or cogl_program_use() are supported by these new drawing apis and if set will simply be silently ignored. Reviewed-by: Neil Roberts <neil@linux.intel.com>
220 lines
7.3 KiB
C
220 lines
7.3 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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#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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typedef struct _CoglAttribute CoglAttribute;
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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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gsize stride,
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gsize 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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gboolean 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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gboolean
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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 handle references a #CoglAttribute,
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* %FALSE otherwise
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*/
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gboolean
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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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