NAME

       glGetSubroutineIndex - retrieve the index of a subroutine uniform of a given shader stage within a
       program

C SPECIFICATION

       GLuint glGetSubroutineIndex(GLuint program, GLenum shadertype, const GLchar *name);

PARAMETERS

       program
           Specifies the name of the program containing shader stage.

       shadertype
           Specifies the shader stage from which to query for subroutine uniform index.  shadertype must be one
           of GL_VERTEX_SHADER, GL_TESS_CONTROL_SHADER, GL_TESS_EVALUATION_SHADER, GL_GEOMETRY_SHADER or
           GL_FRAGMENT_SHADER.

       name
           Specifies the name of the subroutine uniform whose index to query.

DESCRIPTION

       glGetSubroutineIndex returns the index of a subroutine uniform within a shader stage attached to a
       program object.  program contains the name of the program to which the shader is attached.  shadertype
       specifies the stage from which to query shader subroutine index.  name contains the null-terminated name
       of the subroutine uniform whose name to query.

       If name is not the name of a subroutine uniform in the shader stage, GL_INVALID_INDEX is returned, but no
       error is generated. If name is the name of a subroutine uniform in the shader stage, a value between zero
       and the value of GL_ACTIVE_SUBROUTINES minus one will be returned. Subroutine indices are assigned using
       consecutive integers in the range from zero to the value of GL_ACTIVE_SUBROUTINES minus one for the
       shader stage.

ERRORS

       GL_INVALID_ENUM is generated if shadertype or pname is not one of the accepted values.

       GL_INVALID_VALUE is generated if program is not the name of an existing program object.

SEE ALSO

       glGetProgram(), glGetActiveSubroutineUniform(), glGetActiveSubroutineUniformName()

COPYRIGHT

       Copyright © 2010 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.  http://opencontent.org/openpub/.

AUTHORS

       opengl.org

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