GLGETUNIFORMLOCATION(3G) OpenGL 3.3 GLGETUNIFORMLOCATION(3G)
NAME
glGetUniformLocation - Returns the location of a uniform variable
C SPECIFICATION
GLint glGetUniformLocation(GLuint program, const GLchar *name);
PARAMETERS
program
Specifies the program object to be queried.
name
Points to a null terminated string containing the name of the uniform variable whose location is to be queried.
DESCRIPTION
glGetUniformLocation returns an integer that represents the location of a specific uniform variable within a program object. name must be
a null terminated string that contains no white space. name must be an active uniform variable name in program that is not a structure, an
array of structures, or a subcomponent of a vector or a matrix. This function returns -1 if name does not correspond to an active uniform
variable in program or if name starts with the reserved prefix "gl_".
Uniform variables that are structures or arrays of structures may be queried by calling glGetUniformLocation for each field within the
structure. The array element operator "[]" and the structure field operator "." may be used in name in order to select elements within an
array or fields within a structure. The result of using these operators is not allowed to be another structure, an array of structures, or
a subcomponent of a vector or a matrix. Except if the last part of name indicates a uniform variable array, the location of the first
element of an array can be retrieved by using the name of the array, or by using the name appended by "[0]".
The actual locations assigned to uniform variables are not known until the program object is linked successfully. After linking has
occurred, the command glGetUniformLocation can be used to obtain the location of a uniform variable. This location value can then be passed
to glUniform() to set the value of the uniform variable or to glGetUniform() 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. Uniform variable locations and values can only be queried after a link if the link was successful.
ERRORS
GL_INVALID_VALUE is generated if program is not a value generated by OpenGL.
GL_INVALID_OPERATION is generated if program is not a program object.
GL_INVALID_OPERATION is generated if program has not been successfully linked.
ASSOCIATED GETS
glGetActiveUniform() with arguments program and the index of an active uniform variable
glGetProgram() with arguments program and GL_ACTIVE_UNIFORMS or GL_ACTIVE_UNIFORM_MAX_LENGTH
glGetUniform() with arguments program and the name of a uniform variable
glIsProgram()
SEE ALSO
glLinkProgram(), glUniform()
COPYRIGHT
Copyright (C) 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. http://opencontent.org/openpub/.
OpenGL 3.3 03/08/2011 GLGETUNIFORMLOCATION(3G)