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<refentry id="glProgramUniform">
    <refentryinfo>
        <copyright>
            <year>2003-2005</year>
            <holder>3Dlabs Inc. Ltd.</holder>
        </copyright>
        <copyright>
            <year>2010-2013</year>
            <holder>Khronos Group</holder>
        </copyright>
    </refentryinfo>
    <refmeta>
        <refentrytitle>glProgramUniform</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
    <refdescriptor>glProgramUniform</refdescriptor>
        <refname>glProgramUniform1f</refname>
        <refname>glProgramUniform2f</refname>
        <refname>glProgramUniform3f</refname>
        <refname>glProgramUniform4f</refname>
        <refname>glProgramUniform1i</refname>
        <refname>glProgramUniform2i</refname>
        <refname>glProgramUniform3i</refname>
        <refname>glProgramUniform4i</refname>
        <refname>glProgramUniform1ui</refname>
        <refname>glProgramUniform2ui</refname>
        <refname>glProgramUniform3ui</refname>
        <refname>glProgramUniform4ui</refname>
        <refname>glProgramUniform1fv</refname>
        <refname>glProgramUniform2fv</refname>
        <refname>glProgramUniform3fv</refname>
        <refname>glProgramUniform4fv</refname>
        <refname>glProgramUniform1iv</refname>
        <refname>glProgramUniform2iv</refname>
        <refname>glProgramUniform3iv</refname>
        <refname>glProgramUniform4iv</refname>
        <refname>glProgramUniform1uiv</refname>
        <refname>glProgramUniform2uiv</refname>
        <refname>glProgramUniform3uiv</refname>
        <refname>glProgramUniform4uiv</refname>
        <refname>glProgramUniformMatrix2fv</refname>
        <refname>glProgramUniformMatrix3fv</refname>
        <refname>glProgramUniformMatrix4fv</refname>
        <refname>glProgramUniformMatrix2x3fv</refname>
        <refname>glProgramUniformMatrix3x2fv</refname>
        <refname>glProgramUniformMatrix2x4fv</refname>
        <refname>glProgramUniformMatrix4x2fv</refname>
        <refname>glProgramUniformMatrix3x4fv</refname>
        <refname>glProgramUniformMatrix4x3fv</refname>
        <refpurpose>Specify the value of a uniform variable for a specified program object</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
    <funcsynopsis>
        <funcprototype>
        <funcdef>void <function>glProgramUniform1f</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLfloat <parameter>v0</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2f</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLfloat <parameter>v0</parameter></paramdef>
        <paramdef>GLfloat <parameter>v1</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3f</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLfloat <parameter>v0</parameter></paramdef>
        <paramdef>GLfloat <parameter>v1</parameter></paramdef>
        <paramdef>GLfloat <parameter>v2</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4f</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLfloat <parameter>v0</parameter></paramdef>
        <paramdef>GLfloat <parameter>v1</parameter></paramdef>
        <paramdef>GLfloat <parameter>v2</parameter></paramdef>
        <paramdef>GLfloat <parameter>v3</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform1i</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2i</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLint <parameter>v1</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3i</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLint <parameter>v1</parameter></paramdef>
        <paramdef>GLint <parameter>v2</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4i</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLint <parameter>v1</parameter></paramdef>
        <paramdef>GLint <parameter>v2</parameter></paramdef>
        <paramdef>GLint <parameter>v3</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform1ui</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLuint <parameter>v0</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2ui</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLuint <parameter>v1</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3ui</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLint <parameter>v1</parameter></paramdef>
        <paramdef>GLuint <parameter>v2</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4ui</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLint <parameter>v0</parameter></paramdef>
        <paramdef>GLint <parameter>v1</parameter></paramdef>
        <paramdef>GLint <parameter>v2</parameter></paramdef>
        <paramdef>GLuint <parameter>v3</parameter></paramdef>
        </funcprototype>
            <!-- Vector commands -->
        <funcprototype>
        <funcdef>void <function>glProgramUniform1fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform1iv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2iv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3iv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4iv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform1uiv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLuint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform2uiv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLuint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform3uiv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLuint *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniform4uiv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>const GLuint *<parameter>value</parameter></paramdef>
        </funcprototype>
            <!-- Matrix commands -->
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix2fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix3fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix4fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix2x3fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix3x2fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix2x4fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix4x2fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix3x4fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
        <funcprototype>
        <funcdef>void <function>glProgramUniformMatrix4x3fv</function></funcdef>
        <paramdef>GLuint <parameter>program</parameter></paramdef>
        <paramdef>GLint <parameter>location</parameter></paramdef>
        <paramdef>GLsizei <parameter>count</parameter></paramdef>
        <paramdef>GLboolean <parameter>transpose</parameter></paramdef>
        <paramdef>const GLfloat *<parameter>value</parameter></paramdef>
        </funcprototype>
    </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
    <variablelist>
        <varlistentry>
        <term><parameter>program</parameter></term>
        <listitem>
            <para>Specifies the handle of the program containing the uniform
            variable to be modified.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>location</parameter></term>
        <listitem>
            <para>Specifies the location of the uniform variable
            to be modified.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>count</parameter></term>
        <listitem>
            <para>
                For the vector commands
                (<function>glProgramUniform*v</function>), specifies the
                number of elements that are to be modified. This should be 1
                if the targeted uniform variable is not an array, and 1 or
                more if it is an array.
            </para>
            <para>
                For the matrix commands
                (<function>glProgramUniformMatrix*</function>), specifies
                the number of matrices that are to be modified. This should
                be 1 if the targeted uniform variable is not an array of
                matrices, and 1 or more if it is an array of matrices.
            </para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>transpose</parameter></term>
        <listitem>
            <para>
                For the matrix commands, specifies whether to transpose the
                matrix as the values are loaded into the uniform variable.
            </para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term>
            <parameter>v0</parameter>,
            <parameter>v1</parameter>,
            <parameter>v2</parameter>,
            <parameter>v3</parameter>
        </term>
        <listitem>
            <para>
                For the scalar commands, specifies the new values to be used
                for the specified uniform variable.
            </para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>value</parameter></term>
        <listitem>
            <para>
                For the vector and matrix commands, specifies a pointer to
                an array of <parameter>count</parameter> values that will be
                used to update the specified uniform variable.
            </para>
        </listitem>
        </varlistentry>
    </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
    <para><function>glProgramUniform</function> modifies the value of a
    uniform variable or a uniform variable array. The location of
    the uniform variable to be modified is specified by
    <parameter>location</parameter>, which should be a value
    returned by
    <citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>.
    <function>glProgramUniform</function> operates on the program object
    specified by <parameter>program</parameter>.</para>

    <para>The commands <function>glProgramUniform{1|2|3|4}{f|i|ui}</function>
    are used to change the value of the uniform variable specified
    by <parameter>location</parameter> using the values passed as
    arguments. The number specified in the command should match the
    number of components in the data type of the specified uniform
    variable (e.g., <function>1</function> for <code>float</code>, <code>int</code>, <code>unsigned int</code>, <code>bool</code>;
    <function>2</function> for <code>vec2</code>, <code>ivec2</code>, <code>uvec2</code>, <code>bvec2</code>, etc.). The suffix
    <function>f</function> indicates that floating-point values are
    being passed; the suffix <function>i</function> indicates that
    integer values are being passed; the suffix <function>ui</function> indicates that
    unsigned integer values are being passed, and this type should also match
    the data type of the specified uniform variable. The
    <function>i</function> variants of this function should be used
    to provide values for uniform variables defined as <code>int</code>, <code>ivec2</code>,
    <code>ivec3</code>, <code>ivec4</code>, or arrays of these. The
    <function>ui</function> variants of this function should be used
    to provide values for uniform variables defined as <code>unsigned int</code>, <code>uvec2</code>,
    <code>uvec3</code>, <code>uvec4</code>, or arrays of these. The <function>f</function>
    variants should be used to provide values for uniform variables
    of type <code>float</code>, <code>vec2</code>, <code>vec3</code>, <code>vec4</code>, or arrays of these. Either the
    <function>i</function>, <function>ui</function> or <function>f</function> variants
    may be used to provide values for uniform variables of type
    <code>bool</code>, <code>bvec2</code>, <code>bvec3</code>, <code>bvec4</code>, or arrays of these. The uniform
    variable will be set to <code>false</code> if the input value is 0 or 0.0f,
    and it will be set to <code>true</code> otherwise.</para>

    <para>All active uniform variables defined in a program object
    are initialized to 0 when the program object is linked
    successfully. They retain the values assigned to them by a call
    to <function>glProgramUniform</function> until the next successful
    link operation occurs on the program object, when they are once
    again initialized to 0.</para>

    <para>The commands <function>glProgramUniform{1|2|3|4}{f|i|ui}v</function>
    can be used to modify a single uniform variable or a uniform
    variable array. These commands pass a count and a pointer to the
    values to be loaded into a uniform variable or a uniform
    variable array. A count of 1 should be used if modifying the
    value of a single uniform variable, and a count of 1 or greater
    can be used to modify an entire array or part of an array. When
    loading <emphasis>n</emphasis> elements starting at an arbitrary
    position <emphasis>m</emphasis> in a uniform variable array,
    elements <emphasis>m</emphasis> + <emphasis>n</emphasis> - 1 in
    the array will be replaced with the new values. If
    <parameter>m</parameter> + <parameter>n</parameter> - 1 is
    larger than the size of the uniform variable array, values for
    all array elements beyond the end of the array will be ignored.
    The number specified in the name of the command indicates the
    number of components for each element in
    <parameter>value</parameter>, and it should match the number of
    components in the data type of the specified uniform variable
    (e.g., <function>1</function> for <code>float</code>, <code>int</code>, <code>bool</code>;
    <function>2</function> for <code>vec2</code>, <code>ivec2</code>, <code>bvec2</code>, etc.). The data
    type specified in the name of the command must match the data
    type for the specified uniform variable as described previously
    for <function>glProgramUniform{1|2|3|4}{f|i|ui}</function>.</para>

    <para>For uniform variable arrays, each element of the array is
    considered to be of the type indicated in the name of the
    command (e.g., <function>glProgramUniform3f</function> or
    <function>glProgramUniform3fv</function> can be used to load a uniform
    variable array of type vec3). The number of elements of the
    uniform variable array to be modified is specified by
    <parameter>count</parameter></para>

    <para>The commands
    <function>glProgramUniformMatrix{2|3|4|2x3|3x2|2x4|4x2|3x4|4x3}fv</function>
        are used to modify a matrix or an array of matrices. The numbers in the
    command name are interpreted as the dimensionality of the matrix.
    The number <function>2</function> indicates a 2 &#215; 2 matrix
    (i.e., 4 values), the number <function>3</function> indicates a
    3 &#215; 3 matrix (i.e., 9 values), and the number
    <function>4</function> indicates a 4 &#215; 4 matrix (i.e., 16
    values). Non-square matrix dimensionality is explicit, with the first
        number representing the number of columns and the second number
        representing the number of rows.  For example,
        <function>2x4</function> indicates a 2 &#215; 4 matrix with 2 columns
        and 4 rows (i.e., 8 values).
        If <parameter>transpose</parameter> is
    <constant>GL_FALSE</constant>, each matrix is assumed to be
    supplied in column major order. If
    <parameter>transpose</parameter> is
    <constant>GL_TRUE</constant>, each matrix is assumed to be
    supplied in row major order. The <parameter>count</parameter>
    argument indicates the number of matrices to be passed. A count
    of 1 should be used if modifying the value of a single matrix,
    and a count greater than 1 can be used to modify an array of
    matrices.</para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
    <para><function>glProgramUniform1i</function> and
    <function>glProgramUniform1iv</function> are the only two functions
    that may be used to load uniform variables defined as sampler
    types. Loading samplers with any other function will result in a
    <constant>GL_INVALID_OPERATION</constant> error.</para>

    <para>If <parameter>count</parameter> is greater than 1 and the
    indicated uniform variable is not an array, a
    <constant>GL_INVALID_OPERATION</constant> error is generated and the
    specified uniform variable will remain unchanged.</para>

    <para>Other than the preceding exceptions, if the type and size
    of the uniform variable as defined in the shader do not match
    the type and size specified in the name of the command used to
    load its value, a <constant>GL_INVALID_OPERATION</constant> error will
    be generated and the specified uniform variable will remain
    unchanged.</para>

    <para>If <parameter>location</parameter> is a value other than
    -1 and it does not represent a valid uniform variable location
    in within <parameter>program</parameter>, an error will be generated, and
    no changes will be made to the uniform variable storage of
    <parameter>program</parameter>. If <parameter>location</parameter> is
    equal to -1, the data passed in will be silently ignored and the
    specified uniform variable will not be changed.</para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
    <para><constant>GL_INVALID_OPERATION</constant> is generated if
    <parameter>program</parameter> does not refer to a program object owned
    by the GL.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if the
    size of the uniform variable declared in the shader does not
    match the size indicated by the <function>glProgramUniform</function>
    command.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
    the signed or unsigned integer variants of this function is used to load a uniform
    variable of type <code>float</code>, <code>vec2</code>, <code>vec3</code>, <code>vec4</code>, or an array of these,
    or if one of the floating-point variants of this function is
    used to load a uniform variable of type <code>int</code>, <code>ivec2</code>, <code>ivec3</code>,
    <code>ivec4</code>, <code>unsigned int</code>, <code>uvec2</code>, <code>uvec3</code>,
    <code>uvec4</code>, or an array of these.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
    the signed integer variants of this function is used to load a uniform
    variable of type <code>unsigned int</code>, <code>uvec2</code>, <code>uvec3</code>,
    <code>uvec4</code>, or an array of these.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if one of
    the unsigned integer variants of this function is used to load a uniform
    variable of type <code>int</code>, <code>ivec2</code>, <code>ivec3</code>,
    <code>ivec4</code>, or an array of these.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if
    <parameter>location</parameter> is an invalid uniform location
    for <parameter>program</parameter> and
    <parameter>location</parameter> is not equal to -1.</para>

    <para><constant>GL_INVALID_VALUE</constant> is generated if
    <parameter>count</parameter> is less than 0.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if
    <parameter>count</parameter> is greater than 1 and the indicated
    uniform variable is not an array variable.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if a
    sampler is loaded using a command other than
    <function>glProgramUniform1i</function> and
    <function>glProgramUniform1iv</function>.</para>

    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
    <para><citerefentry><refentrytitle>glGetActiveUniform</refentrytitle></citerefentry>
    with the handle of a program object and the index of an active uniform variable</para>

    <para><citerefentry><refentrytitle>glGetUniform</refentrytitle></citerefentry>
    with the handle of a program object and the location of a
    uniform variable</para>

    <para><citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>
    with the handle of a program object and the name of a uniform
    variable</para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
    <para><citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry>,
    <citerefentry><refentrytitle>glUseProgram</refentrytitle></citerefentry></para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 2003-2005 3Dlabs Inc. Ltd.
            Copyright <trademark class="copyright"></trademark> 2010-2013 Khronos Group.
            This material may be distributed subject to the terms and conditions set forth in
            the Open Publication License, v 1.0, 8 June 1999.
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
        </para>
    </refsect1>
</refentry>
