NAME

       glGetUniformfv, glGetUniformiv - Returns the value of a uniform variable

C SPECIFICATION

       void glGetUniformfv(GLuint program, GLint location, GLfloat *params);

       void glGetUniformiv(GLuint program, GLint location, GLint *params);

       void glGetUniformuiv(GLuint program, GLint location, GLuint *params);

       void glGetUniformdv(GLuint program, GLint location, GLdouble *params);

PARAMETERS

       program
           Specifies the program object to be queried.

       location
           Specifies the location of the uniform variable to be queried.

       params
           Returns the value of the specified uniform variable.

DESCRIPTION

       glGetUniform returns in params the value(s) of the specified uniform variable. The type of the uniform
       variable specified by location 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
       glGetUniform for each element of the array. To query values stored in uniform variables declared as
       structures, call glGetUniform for each field in the structure. The values for uniform variables declared
       as a matrix will be returned in column major order.

       The locations assigned to uniform variables are not known until the program object is linked. 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 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. The uniform variable values can only be
       queried after a link if the link was successful.

NOTES

       If an error is generated, no change is made to the contents of params.

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.

       GL_INVALID_OPERATION is generated if location does not correspond to a valid uniform variable location
       for the specified program object.

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

       glGetUniformLocation() with arguments program and the name of a uniform variable

       glIsProgram()

SEE ALSO

       glCreateProgram(), glLinkProgram(), glUniform()

COPYRIGHT

       Copyright © 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/.

AUTHORS

       opengl.org

opengl.org                                         10/22/2013                                   GLGETUNIFORM(3G)