1e68a8d59e
* clutter/cogl/cogl-mesh.h * clutter/cogl/cogl-types.h * clutter/cogl/cogl.h.in * clutter/cogl/common/Makefile.am * clutter/cogl/common/cogl-mesh-private.h * clutter/cogl/common/cogl-mesh.c * clutter/cogl/gl/cogl-context.c * clutter/cogl/gl/cogl-context.h * clutter/cogl/gl/cogl-defines.h.in * clutter/cogl/gl/cogl.c * clutter/cogl/gles/cogl-context.c * clutter/cogl/gles/cogl-context.h * doc/reference/cogl/cogl-docs.sgml * doc/reference/cogl/cogl-sections.txt: The Mesh API provides a means for submitting an extensible number of per vertex attributes to OpenGL in a way that doesn't require format conversions and so that the data can be mapped into the GPU (in vertex buffer objects) for - hopefully - fast re-use. There are a number of things we can potentially use this API for, but right now this just provides a foundation to build on. Please read the extensive list of TODO items in cogl-mesh.c for examples. Please refer to the cogl-mesh section in the reference manual for documentation of the API. * tests/conform/Makefile.am * tests/conform/test-conform-main.c * tests/conform/test-mesh-contiguous.c * tests/conform/test-mesh-interleved.c * tests/conform/test-mesh-mutability.c: Privides basic coverage testing for the mesh API.
287 lines
11 KiB
C
287 lines
11 KiB
C
/* cogl-mesh.h: Handle extensible arrays of vertex attributes
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* This file is part of Clutter
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*
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* Copyright (C) 2008 Intel Corporation.
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*
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* Authored by: Robert Bragg <bob@o-hand.com>
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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
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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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_MESH_H__
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#define __COGL_MESH_H__
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#include <glib.h>
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#include <cogl/cogl-types.h>
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-mesh
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* @short_description: An API for submitting extensible arrays of vertex
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* attributes to OpenGL in a way that aims to minimise
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* copying or reformatting of the original data.
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*
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* The Mesh API is designed to be a fairly raw mechanism for developers
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* to be able to submit geometry to Cogl in a format that can be directly
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* consumed by an OpenGL driver and with awareness of the specific hardware
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* being used then costly format conversion can also be avoided.
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*
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* They are designed to work on top of buffer objects and developers should
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* understand that mesh objects are not cheap to create but once they
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* have been submitted they are stored in GPU addressable memory and can
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* be quickly reused.
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*
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* Although this API does allow you to modify mesh objects after they have
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* been submitted to the GPU you must note that modification is still
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* not cheap, so if at all possible think of tricks that let you reuse
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* a static buffer. To help with this, it is possible to enable and disable
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* individual attributes cheaply.
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*
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* Take for example a mesh representing an elipse. If you were to submit
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* a mesh with color attributes, texture coordinates and normals, then
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* you would be able to draw an elipses in the following different ways
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* without creating a new mesh:
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* <itemizedlist>
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* <listitem>Flat colored elipse</listitem>
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* <listitem>Textured elipse</listitem>
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* <listitem>Smoothly lit textured elipse blended with the color.</listitem>
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* </itemizedlist>
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*
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* Another trick that can be used is submitting a highly detailed mesh
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* and then using cogl_mesh_draw_range_elements to sample lower resolution
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* geometry out from a fixed mesh.
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*
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* The API doesn't currently give you any control over the actual buffer
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* objects that are created, but you can expect that when you first submit
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* your attributes they start off in one or more GL_STATIC_DRAW buffers.
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* If you then update some of your attributes; then these attributes will
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* normally be moved into new GL_DYNAMIC_DRAW draw buffers.
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*/
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/**
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* cogl_mesh_new:
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* @n_vertices: The number of vertices that will make up your mesh.
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*
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* This creates a Cogl handle for a new mesh that you can then start to add
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* attributes too.
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*/
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CoglHandle
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cogl_mesh_new (guint n_vertices);
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/**
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* cogl_mesh_add_attribute:
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* @handle: A Cogl mesh handle
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* @attribute_name: The name of your attribute. It should be a valid GLSL
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* variable name and standard attribute types must use one
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* of following built-in names: (Note: they correspond to the
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* built-in names in GLSL)
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* <itemizedlist>
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* <listitem>"gl_Color"</listitem>
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* <listitem>"gl_Normal"</listitem>
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* <listitem>"gl_MultiTexCoord0, gl_MultiTexCoord1, ..."</listitem>
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* <listitem>"gl_Vertex"</listitem>
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* </itemizedlist>
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* To support adding multiple variations of the same attribute
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* the name can have a detail component, E.g.
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* "gl_Color::active" or "gl_Color::inactive"
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* @n_components: The number of components per attribute and must be 1,2,3 or 4
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* @gl_type: Specifies the data type of each component (GL_BYTE, GL_UNSIGNED_BYTE,
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* GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT or
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* GL_DOUBLE)
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* @normalized: If GL_TRUE, this specifies that values stored in an integer
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* format should be mapped into the range [-1.0, 1.0] or [0.1, 1.0]
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* for unsigned values. If GL_FALSE they are converted to floats
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* directly.
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* @stride: This specifies the number of bytes from the start of one attribute
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* value to the start of the next value (for the same attribute). So
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* for example with a position interleved with color like this:
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* XYRGBAXYRGBAXYRGBA, then if each letter represents a byte, the
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* stride for both attributes is 6. The special value 0 means the
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* values are stored sequentially in memory.
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* @pointer: This addresses the first attribute in the vertex array. (This
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* must remain valid until you call cogl_mesh_submit)
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*
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* This function lets you add an attribute to a mesh. You either use one
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* of the built-in names to add standard attributes, like positions, colors
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* and normals or you can add custom attributes for use in shaders.
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*
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* Note: The number of vertices declared when creating the mesh is used to
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* determine how many attribute values will be read from the supplied pointer.
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*
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* Note: the data supplied here isn't copied anywhere until you call
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* cogl_mesh_submit, so the supplied pointer must remain valid until then.
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* (This is an important optimisation since we can't create a buffer
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* object until we know about all the attributes, and repeatedly copying
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* large buffers of vertex data may be very costly) If you add attributes
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* after submitting then you will need to re-call cogl_mesh_submit to
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* commit the changes to the GPU. (Be carefull to minimize the number of
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* calls to cogl_mesh_submit though)
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*
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* Note: If you are interleving attributes it is assumed that that each
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* interleaved attribute starts no farther than +- stride bytes from
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* the other attributes it is interleved with. I.e. this is ok:
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* |-0-0-0-0-0-0-0-0-0-0|
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* This is not ok:
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* |- - - - -0-0-0-0-0-0 0 0 0 0|
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* (Though you can have multiple groups of interleved attributes)
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*/
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void
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cogl_mesh_add_attribute (CoglHandle handle,
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const char *attribute_name,
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guint8 n_components,
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GLenum gl_type,
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gboolean normalized,
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guint16 stride,
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const void *pointer);
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/**
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* cogl_mesh_delete_attribute:
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* @handle: A Cogl mesh handle
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* @attribute_name: The name of a previously added attribute
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*
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* This function deletes an attribute from a mesh. You will need to
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* call cogl_mesh_submit to commit this change to the GPU.
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*/
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void
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cogl_mesh_delete_attribute (CoglHandle handle,
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const char *attribute_name);
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/**
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* cogl_mesh_enable_attribute:
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* @handle: A Cogl mesh handle
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* @attribute_name: The name of the attribute you want to enable
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*
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* This function enables a previosuly added attribute
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*
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* Since it is costly to create new mesh objects, then to make individual mesh
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* objects more reuseable it is possible to enable and disable attributes
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* before using a mesh for drawing.
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*
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* Note: You don't need to call cogl_mesh_submit after using this function
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*/
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void
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cogl_mesh_enable_attribute (CoglHandle handle,
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const char *attribute_name);
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/**
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* cogl_mesh_disable_attribute:
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* @handle: A Cogl mesh handle
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* @attribute_name: The name of the attribute you want to disable
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*
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* This function disables a previosuly added attribute
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*
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* Since it is costly to create new mesh objects, then to make individual mesh
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* objects more reuseable it is possible to enable and disable attributes
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* before using a mesh for drawing.
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*
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* Note: You don't need to call cogl_mesh_submit after using this function
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*/
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void
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cogl_mesh_disable_attribute (CoglHandle handle,
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const char *attribute_name);
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/**
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* cogl_mesh_draw_arrays:
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* @handle: A Cogl mesh handle
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* @mode: Specifies how the vertices should be interpreted, and should be
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* a valid GL primitive type:
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* <itemizedlist>
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* <listitem>GL_POINTS</listitem>
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* <listitem>GL_LINE_STRIP</listitem>
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* <listitem>GL_LINE_LOOP</listitem>
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* <listitem>GL_LINES</listitem>
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* <listitem>GL_TRIANGLE_STRIP</listitem>
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* <listitem>GL_TRIANGLE_FAN</listitem>
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* <listitem>GL_TRIANGLES</listitem>
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* </itemizedlist>
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* (Note: only types available in GLES are listed)
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* @first: Specifies the index of the first vertex you want to draw with
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* @count: Specifies the number of vertices you want to draw.
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*
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* This function lets you draw geometry using all or a subset of the
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* vertices in a mesh object.
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*/
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void
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cogl_mesh_draw_arrays (CoglHandle handle,
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GLenum mode,
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GLint first,
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GLsizei count);
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/**
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* cogl_mesh_draw_range_elements:
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* @handle: A Cogl mesh handle
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* @mode: Specifies how the vertices should be interpreted, and should be
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* a valid GL primitive type:
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* <itemizedlist>
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* <listitem>GL_POINTS</listitem>
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* <listitem>GL_LINE_STRIP</listitem>
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* <listitem>GL_LINE_LOOP</listitem>
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* <listitem>GL_LINES</listitem>
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* <listitem>GL_TRIANGLE_STRIP</listitem>
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* <listitem>GL_TRIANGLE_FAN</listitem>
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* <listitem>GL_TRIANGLES</listitem>
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* </itemizedlist>
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* (Note: only types available in GLES are listed)
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* @start: Specifies the minimum vertex index contained in indices
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* @end: Specifies the maximum vertex index contained in indices
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* @count: Specifies the number of vertices you want to draw.
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* @type: Specifies the data type used for the indices, and must be
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* one of:
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* <itemizedlist>
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* <listitem>GL_UNSIGNED_BYTE</listitem>
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* <listitem>GL_UNSIGNED_SHORT</listitem>
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* <listitem>GL_UNSIGNED_INT</listitem>
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* </itemizedlist>
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* @indices: Specifies the address of your array of indices
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*
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* This function lets you use an array of indices to specify the vertices
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* within your mesh pbject that you want to draw.
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*/
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void
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cogl_mesh_draw_range_elements (CoglHandle handle,
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GLenum mode,
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GLuint start,
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GLuint end,
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GLsizei count,
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GLenum type,
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const GLvoid *indices);
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/**
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* cogl_mesh_ref:
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* @handle: a @CoglHandle.
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*
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* Increment the reference count for a cogl mesh.
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*
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* Returns: the @handle.
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*/
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CoglHandle cogl_mesh_ref (CoglHandle handle);
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/**
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* cogl_mesh_unref:
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* @handle: a @CoglHandle.
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*
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* Deccrement the reference count for a cogl mesh.
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*/
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void cogl_mesh_unref (CoglHandle handle);
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G_END_DECLS
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#endif /* __COGL_MESH_H__ */
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