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renderer=
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"text/html; charset=UTF-8" /><title>glVertexAttrib
</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.73.2" /></head><body><div class=
"refentry" lang=
"en" xml:
lang=
"en"><a id=
"glVertexAttrib"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>glVertexAttrib — Specifies the value of a generic vertex attribute
</p></div><div class=
"refsynopsisdiv"><h2>C Specification
</h2><div class=
"funcsynopsis"><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1f
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v0
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1s
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v0
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1d
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v0
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2f
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v1
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2s
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v1
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2d
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v1
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3f
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v2
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3s
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v2
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3d
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v2
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4f
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v2
</var>,
</td></tr><tr><td> </td><td>GLfloat
</td><td><var class=
"pdparam">v3
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4s
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v2
</var>,
</td></tr><tr><td> </td><td>GLshort
</td><td><var class=
"pdparam">v3
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4d
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v2
</var>,
</td></tr><tr><td> </td><td>GLdouble
</td><td><var class=
"pdparam">v3
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nub
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>GLubyte
</td><td><var class=
"pdparam">v0
</var>,
</td></tr><tr><td> </td><td>GLubyte
</td><td><var class=
"pdparam">v1
</var>,
</td></tr><tr><td> </td><td>GLubyte
</td><td><var class=
"pdparam">v2
</var>,
</td></tr><tr><td> </td><td>GLubyte
</td><td><var class=
"pdparam">v3
</var><code>)
</code>;
</td></tr></table></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"parameters"></a><h2>Parameters
</h2><div class=
"variablelist"><dl><dt><span class=
"term"><em class=
"parameter"><code>index
</code></em></span></dt><dd><p>Specifies the index of the generic vertex
4 attribute to be modified.
</p></dd><dt><span class=
"term">
5 <em class=
"parameter"><code>v0
</code></em>,
6 <em class=
"parameter"><code>v1
</code></em>,
7 <em class=
"parameter"><code>v2
</code></em>,
8 <em class=
"parameter"><code>v3
</code></em>
9 </span></dt><dd><p>Specifies the new values to be used for the
10 specified vertex attribute.
</p></dd></dl></div></div><div class=
"refsynopsisdiv"><h2>C Specification
</h2><div class=
"funcsynopsis"><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1fv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLfloat *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1sv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLshort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib1dv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLdouble *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2fv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLfloat *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2sv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLshort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib2dv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLdouble *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3fv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLfloat *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3sv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLshort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib3dv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLdouble *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4fv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLfloat *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4sv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLshort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4dv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLdouble *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4iv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLint *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4bv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLbyte *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4ubv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLubyte *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4usv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLushort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4uiv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLuint *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nbv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLbyte *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nsv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLshort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Niv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLint *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nubv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLubyte *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nusv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLushort *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glVertexAttrib4Nuiv
</b>(
</code></td><td>GLuint
</td><td><var class=
"pdparam">index
</var>,
</td></tr><tr><td> </td><td>const GLuint *
</td><td><var class=
"pdparam">v
</var><code>)
</code>;
</td></tr></table></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"parameters2"></a><h2>Parameters
</h2><div class=
"variablelist"><dl><dt><span class=
"term"><em class=
"parameter"><code>index
</code></em></span></dt><dd><p>Specifies the index of the generic vertex
11 attribute to be modified.
</p></dd><dt><span class=
"term"><em class=
"parameter"><code>v
</code></em></span></dt><dd><p>Specifies a pointer to an array of values to
12 be used for the generic vertex attribute.
</p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>OpenGL defines a number of standard vertex attributes that
13 applications can modify with standard API entry points (color,
14 normal, texture coordinates, etc.). The
15 <code class=
"function">glVertexAttrib
</code> family of entry points
16 allows an application to pass generic vertex attributes in
17 numbered locations.
</p><p>Generic attributes are defined as four-component values
18 that are organized into an array. The first entry of this array
19 is numbered
0, and the size of the array is specified by the
20 implementation-dependent constant
21 <code class=
"constant">GL_MAX_VERTEX_ATTRIBS
</code>. Individual elements
22 of this array can be modified with a
23 <code class=
"function">glVertexAttrib
</code> call that specifies the
24 index of the element to be modified and a value for that
25 element.
</p><p>These commands can be used to specify one, two, three, or
26 all four components of the generic vertex attribute specified by
27 <em class=
"parameter"><code>index
</code></em>. A
<code class=
"function">1</code> in the
28 name of the command indicates that only one value is passed, and
29 it will be used to modify the first component of the generic
30 vertex attribute. The second and third components will be set to
31 0, and the fourth component will be set to
1. Similarly, a
32 <code class=
"function">2</code> in the name of the command indicates that
33 values are provided for the first two components, the third
34 component will be set to
0, and the fourth component will be set
35 to
1. A
<code class=
"function">3</code> in the name of the command
36 indicates that values are provided for the first three
37 components and the fourth component will be set to
1, whereas a
38 <code class=
"function">4</code> in the name indicates that values are
39 provided for all four components.
</p><p>The letters
<code class=
"function">s
</code>,
40 <code class=
"function">f
</code>,
<code class=
"function">i
</code>,
41 <code class=
"function">d
</code>,
<code class=
"function">ub
</code>,
42 <code class=
"function">us
</code>, and
<code class=
"function">ui
</code> indicate
43 whether the arguments are of type short, float, int, double,
44 unsigned byte, unsigned short, or unsigned int. When
45 <code class=
"function">v
</code> is appended to the name, the commands can
46 take a pointer to an array of such values. The commands
47 containing
<code class=
"function">N
</code> indicate that the arguments
48 will be passed as fixed-point values that are scaled to a
49 normalized range according to the component conversion rules
50 defined by the OpenGL specification. Signed values are
51 understood to represent fixed-point values in the range [-
1,
1],
52 and unsigned values are understood to represent fixed-point
53 values in the range [
0,
1].
</p><p>OpenGL Shading Language attribute variables are allowed to
54 be of type mat2, mat3, or mat4. Attributes of these types may be
55 loaded using the
<code class=
"function">glVertexAttrib
</code> entry
56 points. Matrices must be loaded into successive generic
57 attribute slots in column major order, with one column of the
58 matrix in each generic attribute slot.
</p><p>A user-defined attribute variable declared in a vertex
59 shader can be bound to a generic attribute index by calling
60 <a class=
"citerefentry" href=
"glBindAttribLocation.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBindAttribLocation
</span></span></a>.
61 This allows an application to use more descriptive variable
62 names in a vertex shader. A subsequent change to the specified
63 generic vertex attribute will be immediately reflected as a
64 change to the corresponding attribute variable in the vertex
65 shader.
</p><p>The binding between a generic vertex attribute index and a
66 user-defined attribute variable in a vertex shader is part of
67 the state of a program object, but the current value of the
68 generic vertex attribute is not. The value of each generic
69 vertex attribute is part of current state, just like standard
70 vertex attributes, and it is maintained even if a different
71 program object is used.
</p><p>An application may freely modify generic vertex attributes
72 that are not bound to a named vertex shader attribute variable.
73 These values are simply maintained as part of current state and
74 will not be accessed by the vertex shader. If a generic vertex
75 attribute bound to an attribute variable in a vertex shader is
76 not updated while the vertex shader is executing, the vertex
77 shader will repeatedly use the current value for the generic
78 vertex attribute.
</p><p>The generic vertex attribute with index
0 is the same as
79 the vertex position attribute previously defined by OpenGL. A
80 <a class=
"citerefentry" href=
"glVertex2.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glVertex2
</span></span></a>,
81 <a class=
"citerefentry" href=
"glVertex3.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glVertex3
</span></span></a>,
83 <a class=
"citerefentry" href=
"glVertex4.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glVertex4
</span></span></a>
84 command is completely equivalent to the corresponding
85 <code class=
"function">glVertexAttrib
</code> command with an index
86 argument of
0. A vertex shader can access generic vertex
87 attribute
0 by using the built-in attribute variable
88 <em class=
"parameter"><code>gl_Vertex
</code></em>. There are no current values
89 for generic vertex attribute
0. This is the only generic vertex
90 attribute with this property; calls to set other standard vertex
91 attributes can be freely mixed with calls to set any of the
92 other generic vertex attributes.
</p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"notes"></a><h2>Notes
</h2><p><code class=
"function">glVertexAttrib
</code> is available only if
93 the GL version is
2.0 or greater.
</p><p>Generic vertex attributes can be updated at any time. In
94 particular,
<code class=
"function">glVertexAttrib
</code> can be called
96 <a class=
"citerefentry" href=
"glBegin.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBegin
</span></span></a>
97 and the corresponding call to
98 <a class=
"citerefentry" href=
"glEnd.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glEnd
</span></span></a>.
</p><p>It is possible for an application to bind more than one
99 attribute name to the same generic vertex attribute index. This
100 is referred to as aliasing, and it is allowed only if just one
101 of the aliased attribute variables is active in the vertex
102 shader, or if no path through the vertex shader consumes more
103 than one of the attributes aliased to the same location. OpenGL
104 implementations are not required to do error checking to detect
105 aliasing, they are allowed to assume that aliasing will not
106 occur, and they are allowed to employ optimizations that work
107 only in the absence of aliasing.
</p><p>There is no provision for binding standard vertex
108 attributes; therefore, it is not possible to alias generic
109 attributes with standard attributes.
</p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"errors"></a><h2>Errors
</h2><p><code class=
"constant">GL_INVALID_VALUE
</code> is generated if
110 <em class=
"parameter"><code>index
</code></em> is greater than or equal to
111 <code class=
"constant">GL_MAX_VERTEX_ATTRIBS
</code>.
</p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"associatedgets"></a><h2>Associated Gets
</h2><p><a class=
"citerefentry" href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a>
112 with the argument
<code class=
"constant">GL_CURRENT_PROGRAM
</code></p><p><a class=
"citerefentry" href=
"glGetActiveAttrib.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetActiveAttrib
</span></span></a>
113 with argument
<em class=
"parameter"><code>program
</code></em> and the index of an active
114 attribute variable
</p><p><a class=
"citerefentry" href=
"glGetAttribLocation.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetAttribLocation
</span></span></a>
115 with argument
<em class=
"parameter"><code>program
</code></em> and an attribute
116 variable name
</p><p><a class=
"citerefentry" href=
"glGetVertexAttrib.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetVertexAttrib
</span></span></a>
117 with arguments
<code class=
"constant">GL_CURRENT_VERTEX_ATTRIB
</code> and
118 <em class=
"parameter"><code>index
</code></em></p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p><a class=
"citerefentry" href=
"glBindAttribLocation.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBindAttribLocation
</span></span></a>,
119 <a class=
"citerefentry" href=
"glVertex.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glVertex
</span></span></a>,
120 <a class=
"citerefentry" href=
"glVertexAttribPointer.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glVertexAttribPointer
</span></span></a></p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
121 Copyright
<span class=
"trademark"></span>©
2003-
2005 3Dlabs Inc. Ltd.
122 This material may be distributed subject to the terms and conditions set forth in
123 the Open Publication License, v
1.0,
8 June
1999.
124 <a class=
"ulink" href=
"http://opencontent.org/openpub/" target=
"_top">http://opencontent.org/openpub/
</a>.
125 </p></div></div></body></html>
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