'\" t
.\"     Title: glGetUniform
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
.\"      Date: 05/30/2012
.\"    Manual: [FIXME: manual]
.\"    Source: [FIXME: source]
.\"  Language: English
.\"
.TH "GLGETUNIFORM" "3G" "05/30/2012" "[FIXME: source]" "[FIXME: manual]"
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.SH "NAME"
glGetUniformfv, glGetUniformiv \- Returns the value of a uniform variable
.SH "C SPECIFICATION"
.HP \w'void\ glGetUniformfv('u
.BI "void glGetUniformfv(GLuint\ " "program" ", GLint\ " "location" ", GLfloat\ *" "params" ");"
.HP \w'void\ glGetUniformiv('u
.BI "void glGetUniformiv(GLuint\ " "program" ", GLint\ " "location" ", GLint\ *" "params" ");"
.SH "PARAMETERS"
.PP
\fIprogram\fR
.RS 4
Specifies the program object to be queried\&.
.RE
.PP
\fIlocation\fR
.RS 4
Specifies the location of the uniform variable to be queried\&.
.RE
.PP
\fIparams\fR
.RS 4
Returns the value of the specified uniform variable\&.
.RE
.SH "DESCRIPTION"
.PP
\fBglGetUniform\fR
returns in
\fIparams\fR
the value(s) of the specified uniform variable\&. The type of the uniform variable specified by
\fIlocation\fR
determines the number of values returned\&. If the uniform variable is defined in the shader as a boolean, int, or float, a single value will be returned\&. If it is defined as a vec2, ivec2, or bvec2, two values will be returned\&. If it is defined as a vec3, ivec3, or bvec3, three values will be returned, and so on\&. To query values stored in uniform variables declared as arrays, call
\fBglGetUniform\fR
for each element of the array\&. To query values stored in uniform variables declared as structures, call
\fBglGetUniform\fR
for each field in the structure\&. The values for uniform variables declared as a matrix will be returned in column major order\&.
.PP
The locations assigned to uniform variables are not known until the program object is linked\&. After linking has occurred, the command
\fBglGetUniformLocation\fR()
can be used to obtain the location of a uniform variable\&. This location value can then be passed to
\fBglGetUniform\fR
in order to query the current value of the uniform variable\&. After a program object has been linked successfully, the index values for uniform variables remain fixed until the next link command occurs\&. The uniform variable values can only be queried after a link if the link was successful\&.
.SH "NOTES"
.PP
If an error is generated, no change is made to the contents of
\fIparams\fR\&.
.SH "ERRORS"
.PP
\fBGL_INVALID_VALUE\fR
is generated if
\fIprogram\fR
is not a value generated by OpenGL\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if
\fIprogram\fR
is not a program object\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if
\fIprogram\fR
has not been successfully linked\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if
\fIlocation\fR
does not correspond to a valid uniform variable location for the specified program object\&.
.SH "ASSOCIATED GETS"
.PP
\fBglGetActiveUniform\fR()
with arguments
\fIprogram\fR
and the index of an active uniform variable
.PP
\fBglGetProgram\fR()
with arguments
\fIprogram\fR
and
\fBGL_ACTIVE_UNIFORMS\fR
or
\fBGL_ACTIVE_UNIFORM_MAX_LENGTH\fR
.PP
\fBglGetUniformLocation\fR()
with arguments
\fIprogram\fR
and the name of a uniform variable
.PP
\fBglIsProgram\fR()
.SH "SEE ALSO"
.PP
\fBglCreateProgram\fR(),
\fBglLinkProgram\fR(),
\fBglUniform\fR()
.SH "COPYRIGHT"
.PP
Copyright
\(co
2003\-2005 3Dlabs Inc\&. Ltd\&. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1\&.0, 8 June 1999\&.
\m[blue]\fBhttp://opencontent\&.org/openpub/\fR\m[]\&.