upstream-doc/man4/glUniform.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3           "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glUniform">
   5     <refmeta>
   6     <refentrytitle>glUniform</refentrytitle>
   7     <manvolnum>3G</manvolnum>
   8     </refmeta>
   9     <refnamediv>
  10     <refdescriptor>glUniform</refdescriptor>
  11     <refname>glUniform1f</refname>
  12     <refname>glUniform2f</refname>
  13     <refname>glUniform3f</refname>
  14     <refname>glUniform4f</refname>
  15     <refname>glUniform1i</refname>
  16     <refname>glUniform2i</refname>
  17     <refname>glUniform3i</refname>
  18     <refname>glUniform4i</refname>
  19     <refname>glUniform1ui</refname>
  20     <refname>glUniform2ui</refname>
  21     <refname>glUniform3ui</refname>
  22     <refname>glUniform4ui</refname>
  23     <refname>glUniform1fv</refname>
  24     <refname>glUniform2fv</refname>
  25     <refname>glUniform3fv</refname>
  26     <refname>glUniform4fv</refname>
  27     <refname>glUniform1iv</refname>
  28     <refname>glUniform2iv</refname>
  29     <refname>glUniform3iv</refname>
  30     <refname>glUniform4iv</refname>
  31     <refname>glUniform1uiv</refname>
  32     <refname>glUniform2uiv</refname>
  33     <refname>glUniform3uiv</refname>
  34     <refname>glUniform4uiv</refname>
  35     <refname>glUniformMatrix2fv</refname>
  36     <refname>glUniformMatrix3fv</refname>
  37     <refname>glUniformMatrix4fv</refname>
  38     <refname>glUniformMatrix2x3fv</refname>
  39     <refname>glUniformMatrix3x2fv</refname>
  40     <refname>glUniformMatrix2x4fv</refname>
  41     <refname>glUniformMatrix4x2fv</refname>
  42     <refname>glUniformMatrix3x4fv</refname>
  43     <refname>glUniformMatrix4x3fv</refname>
  44     <refpurpose>Specify the value of a uniform variable for the current program object</refpurpose>
  45     </refnamediv>
  46     <refsynopsisdiv><title>C Specification</title>
  47     <funcsynopsis>
  48         <funcprototype>
  49         <funcdef>void <function>glUniform1f</function></funcdef>
  50         <paramdef>GLint <parameter>location</parameter></paramdef>
  51         <paramdef>GLfloat <parameter>v0</parameter></paramdef>
  52         </funcprototype>
  53         <funcprototype>
  54         <funcdef>void <function>glUniform2f</function></funcdef>
  55         <paramdef>GLint <parameter>location</parameter></paramdef>
  56         <paramdef>GLfloat <parameter>v0</parameter></paramdef>
  57         <paramdef>GLfloat <parameter>v1</parameter></paramdef>
  58         </funcprototype>
  59         <funcprototype>
  60         <funcdef>void <function>glUniform3f</function></funcdef>
  61         <paramdef>GLint <parameter>location</parameter></paramdef>
  62         <paramdef>GLfloat <parameter>v0</parameter></paramdef>
  63         <paramdef>GLfloat <parameter>v1</parameter></paramdef>
  64         <paramdef>GLfloat <parameter>v2</parameter></paramdef>
  65         </funcprototype>
  66         <funcprototype>
  67         <funcdef>void <function>glUniform4f</function></funcdef>
  68         <paramdef>GLint <parameter>location</parameter></paramdef>
  69         <paramdef>GLfloat <parameter>v0</parameter></paramdef>
  70         <paramdef>GLfloat <parameter>v1</parameter></paramdef>
  71         <paramdef>GLfloat <parameter>v2</parameter></paramdef>
  72         <paramdef>GLfloat <parameter>v3</parameter></paramdef>
  73         </funcprototype>
  74         <funcprototype>
  75         <funcdef>void <function>glUniform1i</function></funcdef>
  76         <paramdef>GLint <parameter>location</parameter></paramdef>
  77         <paramdef>GLint <parameter>v0</parameter></paramdef>
  78         </funcprototype>
  79         <funcprototype>
  80         <funcdef>void <function>glUniform2i</function></funcdef>
  81         <paramdef>GLint <parameter>location</parameter></paramdef>
  82         <paramdef>GLint <parameter>v0</parameter></paramdef>
  83         <paramdef>GLint <parameter>v1</parameter></paramdef>
  84         </funcprototype>
  85         <funcprototype>
  86         <funcdef>void <function>glUniform3i</function></funcdef>
  87         <paramdef>GLint <parameter>location</parameter></paramdef>
  88         <paramdef>GLint <parameter>v0</parameter></paramdef>
  89         <paramdef>GLint <parameter>v1</parameter></paramdef>
  90         <paramdef>GLint <parameter>v2</parameter></paramdef>
  91         </funcprototype>
  92         <funcprototype>
  93         <funcdef>void <function>glUniform4i</function></funcdef>
  94         <paramdef>GLint <parameter>location</parameter></paramdef>
  95         <paramdef>GLint <parameter>v0</parameter></paramdef>
  96         <paramdef>GLint <parameter>v1</parameter></paramdef>
  97         <paramdef>GLint <parameter>v2</parameter></paramdef>
  98         <paramdef>GLint <parameter>v3</parameter></paramdef>
  99         </funcprototype>
 100         <funcprototype>
 101         <funcdef>void <function>glUniform1ui</function></funcdef>
 102         <paramdef>GLint <parameter>location</parameter></paramdef>
 103         <paramdef>GLuint <parameter>v0</parameter></paramdef>
 104         </funcprototype>
 105         <funcprototype>
 106         <funcdef>void <function>glUniform2ui</function></funcdef>
 107         <paramdef>GLint <parameter>location</parameter></paramdef>
 108         <paramdef>GLuint <parameter>v0</parameter></paramdef>
 109         <paramdef>GLuint <parameter>v1</parameter></paramdef>
 110         </funcprototype>
 111         <funcprototype>
 112         <funcdef>void <function>glUniform3ui</function></funcdef>
 113         <paramdef>GLint <parameter>location</parameter></paramdef>
 114         <paramdef>GLuint <parameter>v0</parameter></paramdef>
 115         <paramdef>GLuint <parameter>v1</parameter></paramdef>
 116         <paramdef>GLuint <parameter>v2</parameter></paramdef>
 117         </funcprototype>
 118         <funcprototype>
 119         <funcdef>void <function>glUniform4ui</function></funcdef>
 120         <paramdef>GLint <parameter>location</parameter></paramdef>
 121         <paramdef>GLuint <parameter>v0</parameter></paramdef>
 122         <paramdef>GLuint <parameter>v1</parameter></paramdef>
 123         <paramdef>GLuint <parameter>v2</parameter></paramdef>
 124         <paramdef>GLuint <parameter>v3</parameter></paramdef>
 125         </funcprototype>
 126     </funcsynopsis>
 127     </refsynopsisdiv>
 128     <refsect1 id="parameters"><title>Parameters</title>
 129     <variablelist>
 130         <varlistentry>
 131         <term><parameter>location</parameter></term>
 132         <listitem>
 133             <para>Specifies the location of the uniform variable
 134             to be modified.</para>
 135         </listitem>
 136         </varlistentry>
 137         <varlistentry>
 138         <term>
 139             <parameter>v0</parameter>,
 140             <parameter>v1</parameter>,
 141             <parameter>v2</parameter>,
 142             <parameter>v3</parameter>
 143         </term>
 144         <listitem>
 145             <para>Specifies the new values to be used for the
 146             specified uniform variable.</para>
 147         </listitem>
 148         </varlistentry>
 149     </variablelist>
 150     </refsect1>
 151     <refsynopsisdiv><title>C Specification</title>
 152     <funcsynopsis>
 153         <funcprototype>
 154         <funcdef>void <function>glUniform1fv</function></funcdef>
 155         <paramdef>GLint <parameter>location</parameter></paramdef>
 156         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 157         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 158         </funcprototype>
 159         <funcprototype>
 160         <funcdef>void <function>glUniform2fv</function></funcdef>
 161         <paramdef>GLint <parameter>location</parameter></paramdef>
 162         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 163         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 164         </funcprototype>
 165         <funcprototype>
 166         <funcdef>void <function>glUniform3fv</function></funcdef>
 167         <paramdef>GLint <parameter>location</parameter></paramdef>
 168         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 169         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 170         </funcprototype>
 171         <funcprototype>
 172         <funcdef>void <function>glUniform4fv</function></funcdef>
 173         <paramdef>GLint <parameter>location</parameter></paramdef>
 174         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 175         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 176         </funcprototype>
 177         <funcprototype>
 178         <funcdef>void <function>glUniform1iv</function></funcdef>
 179         <paramdef>GLint <parameter>location</parameter></paramdef>
 180         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 181         <paramdef>const GLint *<parameter>value</parameter></paramdef>
 182         </funcprototype>
 183         <funcprototype>
 184         <funcdef>void <function>glUniform2iv</function></funcdef>
 185         <paramdef>GLint <parameter>location</parameter></paramdef>
 186         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 187         <paramdef>const GLint *<parameter>value</parameter></paramdef>
 188         </funcprototype>
 189         <funcprototype>
 190         <funcdef>void <function>glUniform3iv</function></funcdef>
 191         <paramdef>GLint <parameter>location</parameter></paramdef>
 192         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 193         <paramdef>const GLint *<parameter>value</parameter></paramdef>
 194         </funcprototype>
 195         <funcprototype>
 196         <funcdef>void <function>glUniform4iv</function></funcdef>
 197         <paramdef>GLint <parameter>location</parameter></paramdef>
 198         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 199         <paramdef>const GLint *<parameter>value</parameter></paramdef>
 200         </funcprototype>
 201         <funcprototype>
 202         <funcdef>void <function>glUniform1uiv</function></funcdef>
 203         <paramdef>GLint <parameter>location</parameter></paramdef>
 204         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 205         <paramdef>const GLuint *<parameter>value</parameter></paramdef>
 206         </funcprototype>
 207         <funcprototype>
 208         <funcdef>void <function>glUniform2uiv</function></funcdef>
 209         <paramdef>GLint <parameter>location</parameter></paramdef>
 210         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 211         <paramdef>const GLuint *<parameter>value</parameter></paramdef>
 212         </funcprototype>
 213         <funcprototype>
 214         <funcdef>void <function>glUniform3uiv</function></funcdef>
 215         <paramdef>GLint <parameter>location</parameter></paramdef>
 216         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 217         <paramdef>const GLuint *<parameter>value</parameter></paramdef>
 218         </funcprototype>
 219         <funcprototype>
 220         <funcdef>void <function>glUniform4uiv</function></funcdef>
 221         <paramdef>GLint <parameter>location</parameter></paramdef>
 222         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 223         <paramdef>const GLuint *<parameter>value</parameter></paramdef>
 224         </funcprototype>
 225     </funcsynopsis>
 226     </refsynopsisdiv>
 227     <refsect1 id="parameters2"><title>Parameters</title>
 228     <variablelist>
 229         <varlistentry>
 230         <term><parameter>location</parameter></term>
 231         <listitem>
 232             <para>Specifies the location of the uniform value to
 233             be modified.</para>
 234         </listitem>
 235         </varlistentry>
 236         <varlistentry>
 237         <term><parameter>count</parameter></term>
 238         <listitem>
 239             <para>Specifies the number of elements that are to
 240             be modified. This should be 1 if the targeted
 241             uniform variable is not an array, and 1 or more if it is
 242             an array.</para>
 243         </listitem>
 244         </varlistentry>
 245         <varlistentry>
 246         <term><parameter>value</parameter></term>
 247         <listitem>
 248             <para>Specifies a pointer to an array of
 249             <parameter>count</parameter> values that will be
 250             used to update the specified uniform
 251             variable.</para>
 252         </listitem>
 253         </varlistentry>
 254     </variablelist>
 255     </refsect1>
 256     <refsynopsisdiv><title>C Specification</title>
 257     <funcsynopsis>
 258         <funcprototype>
 259         <funcdef>void <function>glUniformMatrix2fv</function></funcdef>
 260         <paramdef>GLint <parameter>location</parameter></paramdef>
 261         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 262         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 263         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 264         </funcprototype>
 265         <funcprototype>
 266         <funcdef>void <function>glUniformMatrix3fv</function></funcdef>
 267         <paramdef>GLint <parameter>location</parameter></paramdef>
 268         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 269         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 270         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 271         </funcprototype>
 272         <funcprototype>
 273         <funcdef>void <function>glUniformMatrix4fv</function></funcdef>
 274         <paramdef>GLint <parameter>location</parameter></paramdef>
 275         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 276         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 277         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 278         </funcprototype>
 279         <funcprototype>
 280         <funcdef>void <function>glUniformMatrix2x3fv</function></funcdef>
 281         <paramdef>GLint <parameter>location</parameter></paramdef>
 282         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 283         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 284         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 285         </funcprototype>
 286         <funcprototype>
 287         <funcdef>void <function>glUniformMatrix3x2fv</function></funcdef>
 288         <paramdef>GLint <parameter>location</parameter></paramdef>
 289         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 290         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 291         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 292         </funcprototype>
 293         <funcprototype>
 294         <funcdef>void <function>glUniformMatrix2x4fv</function></funcdef>
 295         <paramdef>GLint <parameter>location</parameter></paramdef>
 296         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 297         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 298         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 299         </funcprototype>
 300         <funcprototype>
 301         <funcdef>void <function>glUniformMatrix4x2fv</function></funcdef>
 302         <paramdef>GLint <parameter>location</parameter></paramdef>
 303         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 304         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 305         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 306         </funcprototype>
 307         <funcprototype>
 308         <funcdef>void <function>glUniformMatrix3x4fv</function></funcdef>
 309         <paramdef>GLint <parameter>location</parameter></paramdef>
 310         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 311         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 312         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 313         </funcprototype>
 314         <funcprototype>
 315         <funcdef>void <function>glUniformMatrix4x3fv</function></funcdef>
 316         <paramdef>GLint <parameter>location</parameter></paramdef>
 317         <paramdef>GLsizei <parameter>count</parameter></paramdef>
 318         <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
 319         <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
 320         </funcprototype>
 321     </funcsynopsis>
 322     </refsynopsisdiv>
 323     <refsect1 id="parameters3"><title>Parameters</title>
 324     <variablelist>
 325         <varlistentry>
 326         <term><parameter>location</parameter></term>
 327         <listitem>
 328             <para>Specifies the location of the uniform value to
 329             be modified.</para>
 330         </listitem>
 331         </varlistentry>
 332         <varlistentry>
 333         <term><parameter>count</parameter></term>
 334         <listitem>
 335             <para>Specifies the number of matrices that are to
 336             be modified. This should be 1 if the targeted
 337             uniform variable is not an array of matrices, and 1 or more if it is
 338             an array of matrices.</para>
 339         </listitem>
 340         </varlistentry>
 341         <varlistentry>
 342         <term><parameter>transpose</parameter></term>
 343         <listitem>
 344             <para>Specifies whether to transpose the matrix as
 345             the values are loaded into the uniform
 346             variable.</para>
 347         </listitem>
 348         </varlistentry>
 349         <varlistentry>
 350         <term><parameter>value</parameter></term>
 351         <listitem>
 352             <para>Specifies a pointer to an array of
 353             <parameter>count</parameter> values that will be
 354             used to update the specified uniform
 355             variable.</para>
 356         </listitem>
 357         </varlistentry>
 358     </variablelist>
 359     </refsect1>
 360     <refsect1 id="description"><title>Description</title>
 361     <para><function>glUniform</function> modifies the value of a
 362     uniform variable or a uniform variable array. The location of
 363     the uniform variable to be modified is specified by
 364     <parameter>location</parameter>, which should be a value
 365     returned by
 366     <citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>.
 367     <function>glUniform</function> operates on the program object
 368     that was made part of current state by calling
 369     <citerefentry><refentrytitle>glUseProgram</refentrytitle></citerefentry>.</para>
 370
 371     <para>The commands <function>glUniform{1|2|3|4}{f|i|ui}</function>
 372     are used to change the value of the uniform variable specified
 373     by <parameter>location</parameter> using the values passed as
 374     arguments. The number specified in the command should match the
 375     number of components in the data type of the specified uniform
 376     variable (e.g., <function>1</function> for <code>float</code>, <code>int</code>, <code>unsigned int</code>, <code>bool</code>;
 377     <function>2</function> for <code>vec2</code>, <code>ivec2</code>, <code>uvec2</code>, <code>bvec2</code>, etc.). The suffix
 378     <function>f</function> indicates that floating-point values are
 379     being passed; the suffix <function>i</function> indicates that
 380     integer values are being passed; the suffix <function>ui</function> indicates that
 381     unsigned integer values are being passed, and this type should also match
 382     the data type of the specified uniform variable. The
 383     <function>i</function> variants of this function should be used
 384     to provide values for uniform variables defined as <code>int</code>, <code>ivec2</code>,
 385     <code>ivec3</code>, <code>ivec4</code>, or arrays of these. The
 386     <function>ui</function> variants of this function should be used
 387     to provide values for uniform variables defined as <code>unsigned int</code>, <code>uvec2</code>,
 388     <code>uvec3</code>, <code>uvec4</code>, or arrays of these. The <function>f</function>
 389     variants should be used to provide values for uniform variables
 390     of type <code>float</code>, <code>vec2</code>, <code>vec3</code>, <code>vec4</code>, or arrays of these. Either the
 391     <function>i</function>, <function>ui</function> or <function>f</function> variants
 392     may be used to provide values for uniform variables of type
 393     <code>bool</code>, <code>bvec2</code>, <code>bvec3</code>, <code>bvec4</code>, or arrays of these. The uniform
 394     variable will be set to <code>false</code> if the input value is 0 or 0.0f,
 395     and it will be set to <code>true</code> otherwise.</para>
 396
 397     <para>All active uniform variables defined in a program object
 398     are initialized to 0 when the program object is linked
 399     successfully. They retain the values assigned to them by a call
 400     to <function>glUniform </function> until the next successful
 401     link operation occurs on the program object, when they are once
 402     again initialized to 0.</para>
 403
 404     <para>The commands <function>glUniform{1|2|3|4}{f|i|ui}v</function>
 405     can be used to modify a single uniform variable or a uniform
 406     variable array. These commands pass a count and a pointer to the
 407     values to be loaded into a uniform variable or a uniform
 408     variable array. A count of 1 should be used if modifying the
 409     value of a single uniform variable, and a count of 1 or greater
 410     can be used to modify an entire array or part of an array. When
 411     loading <emphasis>n</emphasis> elements starting at an arbitrary
 412     position <emphasis>m</emphasis> in a uniform variable array,
 413     elements <emphasis>m</emphasis> + <emphasis>n</emphasis> - 1 in
 414     the array will be replaced with the new values. If
 415     <parameter>m</parameter> + <parameter>n</parameter> - 1 is
 416     larger than the size of the uniform variable array, values for
 417     all array elements beyond the end of the array will be ignored.
 418     The number specified in the name of the command indicates the
 419     number of components for each element in
 420     <parameter>value</parameter>, and it should match the number of
 421     components in the data type of the specified uniform variable
 422     (e.g., <function>1</function> for float, int, bool;
 423     <function>2</function> for vec2, ivec2, bvec2, etc.). The data
 424     type specified in the name of the command must match the data
 425     type for the specified uniform variable as described previously
 426     for <function>glUniform{1|2|3|4}{f|i|ui}</function>.</para>
 427
 428     <para>For uniform variable arrays, each element of the array is
 429     considered to be of the type indicated in the name of the
 430     command (e.g., <function>glUniform3f</function> or
 431     <function>glUniform3fv</function> can be used to load a uniform
 432     variable array of type vec3). The number of elements of the
 433     uniform variable array to be modified is specified by
 434     <parameter>count</parameter></para>
 435
 436     <para>The commands
 437     <function>glUniformMatrix{2|3|4|2x3|3x2|2x4|4x2|3x4|4x3}fv</function>
 438         are used to modify a matrix or an array of matrices. The numbers in the
 439     command name are interpreted as the dimensionality of the matrix.
 440     The number <function>2</function> indicates a 2 &#215; 2 matrix
 441     (i.e., 4 values), the number <function>3</function> indicates a
 442     3 &#215; 3 matrix (i.e., 9 values), and the number
 443     <function>4</function> indicates a 4 &#215; 4 matrix (i.e., 16
 444     values). Non-square matrix dimensionality is explicit, with the first
 445         number representing the number of columns and the second number
 446         representing the number of rows.  For example,
 447         <function>2x4</function> indicates a 2 &#215; 4 matrix with 2 columns
 448         and 4 rows (i.e., 8 values).
 449         If <parameter>transpose</parameter> is
 450     <constant>GL_FALSE</constant>, each matrix is assumed to be
 451     supplied in column major order. If
 452     <parameter>transpose</parameter> is
 453     <constant>GL_TRUE</constant>, each matrix is assumed to be
 454     supplied in row major order. The <parameter>count</parameter>
 455     argument indicates the number of matrices to be passed. A count
 456     of 1 should be used if modifying the value of a single matrix,
 457     and a count greater than 1 can be used to modify an array of
 458     matrices.</para>
 459     </refsect1>
 460     <refsect1 id="notes"><title>Notes</title>
 461     <para><function>glUniform1i</function> and
 462     <function>glUniform1iv</function> are the only two functions
 463     that may be used to load uniform variables defined as sampler
 464     types. Loading samplers with any other function will result in a
 465     <constant>GL_INVALID_OPERATION</constant> error.</para>
 466
 467     <para>If <parameter>count</parameter> is greater than 1 and the
 468     indicated uniform variable is not an array, a
 469     <constant>GL_INVALID_OPERATION</constant> error is generated and the
 470     specified uniform variable will remain unchanged.</para>
 471
 472     <para>Other than the preceding exceptions, if the type and size
 473     of the uniform variable as defined in the shader do not match
 474     the type and size specified in the name of the command used to
 475     load its value, a <constant>GL_INVALID_OPERATION</constant> error will
 476     be generated and the specified uniform variable will remain
 477     unchanged.</para>
 478
 479     <para>If <parameter>location</parameter> is a value other than
 480     -1 and it does not represent a valid uniform variable location
 481     in the current program object, an error will be generated, and
 482     no changes will be made to the uniform variable storage of the
 483     current program object. If <parameter>location</parameter> is
 484     equal to -1, the data passed in will be silently ignored and the
 485     specified uniform variable will not be changed.</para>
 486     </refsect1>
 487     <refsect1 id="errors"><title>Errors</title>
 488     <para><constant>GL_INVALID_OPERATION</constant> is generated if there
 489     is no current program object.</para>
 490
 491     <para><constant>GL_INVALID_OPERATION</constant> is generated if the
 492     size of the uniform variable declared in the shader does not
 493     match the size indicated by the <function>glUniform</function>
 494     command.</para>
 495
 496     <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
 497     the signed or unsigned integer variants of this function is used to load a uniform
 498     variable of type <code>float</code>, <code>vec2</code>, <code>vec3</code>, <code>vec4</code>, or an array of these,
 499     or if one of the floating-point variants of this function is
 500     used to load a uniform variable of type <code>int</code>, <code>ivec2</code>, <code>ivec3</code>,
 501     <code>ivec4</code>, <code>unsigned int</code>, <code>uvec2</code>, <code>uvec3</code>,
 502     <code>uvec4</code>, or an array of these.</para>
 503
 504     <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
 505     the signed integer variants of this function is used to load a uniform
 506     variable of type <code>unsigned int</code>, <code>uvec2</code>, <code>uvec3</code>,
 507     <code>uvec4</code>, or an array of these.</para>
 508
 509     <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
 510     the unsigned integer variants of this function is used to load a uniform
 511     variable of type <code>int</code>, <code>ivec2</code>, <code>ivec3</code>,
 512     <code>ivec4</code>, or an array of these.</para>
 513
 514     <para><constant>GL_INVALID_OPERATION</constant> is generated if
 515     <parameter>location</parameter> is an invalid uniform location
 516     for the current program object and
 517     <parameter>location</parameter> is not equal to -1.</para>
 518
 519     <para><constant>GL_INVALID_VALUE</constant> is generated if
 520     <parameter>count</parameter> is less than 0.</para>
 521
 522     <para><constant>GL_INVALID_OPERATION</constant> is generated if
 523     <parameter>count</parameter> is greater than 1 and the indicated
 524     uniform variable is not an array variable.</para>
 525
 526     <para><constant>GL_INVALID_OPERATION</constant> is generated if a
 527     sampler is loaded using a command other than
 528     <function>glUniform1i</function> and
 529     <function>glUniform1iv</function>.</para>
 530
 531     </refsect1>
 532     <refsect1 id="associatedgets"><title>Associated Gets</title>
 533     <para><citerefentry><refentrytitle>glGet</refentrytitle></citerefentry>
 534     with the argument <constant>GL_CURRENT_PROGRAM</constant></para>
 535
 536     <para><citerefentry><refentrytitle>glGetActiveUniform</refentrytitle></citerefentry>
 537     with the handle of a program object and the index of an active uniform variable</para>
 538
 539     <para><citerefentry><refentrytitle>glGetUniform</refentrytitle></citerefentry>
 540     with the handle of a program object and the location of a
 541     uniform variable</para>
 542
 543     <para><citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>
 544     with the handle of a program object and the name of a uniform
 545     variable</para>
 546     </refsect1>
 547     <refsect1 id="seealso"><title>See Also</title>
 548     <para><citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry>,
 549     <citerefentry><refentrytitle>glUseProgram</refentrytitle></citerefentry></para>
 550     </refsect1>
 551     <refsect1 id="Copyright"><title>Copyright</title>
 552         <para>
 553             Copyright <trademark class="copyright"></trademark> 2003-2005 3Dlabs Inc. Ltd.
 554             Copyright <trademark class="copyright"></trademark> 2010 Khronos Group.
 555             This material may be distributed subject to the terms and conditions set forth in
 556             the Open Publication License, v 1.0, 8 June 1999.
 557             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 558         </para>
 559     </refsect1>
 560 </refentry>