GLUSEPROGRAM(3G)						    OpenGL 3.3							  GLUSEPROGRAM(3G)

NAME

       glUseProgram - Installs a program object as part of current rendering state

C SPECIFICATION

       void glUseProgram(GLuint program);

PARAMETERS

       program
	   Specifies the handle of the program object whose executables are to be used as part of current rendering state.

DESCRIPTION

       glUseProgram installs the program object specified by program as part of current rendering state. One or more executables are created in a
       program object by successfully attaching shader objects to it with glAttachShader(), successfully compiling the shader objects with
       glCompileShader(), and successfully linking the program object with glLinkProgram().

       A program object will contain an executable that will run on the vertex processor if it contains one or more shader objects of type
       GL_VERTEX_SHADER that have been successfully compiled and linked. A program object will contain an executable that will run on the geometry
       processor if it contains one or more shader objects of type GL_GEOMETRY_SHADER that have been successfully compiled and linked. Similarly,
       a program object will contain an executable that will run on the fragment processor if it contains one or more shader objects of type
       GL_FRAGMENT_SHADER that have been successfully compiled and linked.

       While a program object is in use, applications are free to modify attached shader objects, compile attached shader objects, attach
       additional shader objects, and detach or delete shader objects. None of these operations will affect the executables that are part of the
       current state. However, relinking the program object that is currently in use will install the program object as part of the current
       rendering state if the link operation was successful (see glLinkProgram() ). If the program object currently in use is relinked
       unsuccessfully, its link status will be set to GL_FALSE, but the executables and associated state will remain part of the current state
       until a subsequent call to glUseProgram removes it from use. After it is removed from use, it cannot be made part of current state until it
       has been successfully relinked.

       If program is zero, then the current rendering state refers to an invalid program object and the results of shader execution are undefined.
       However, this is not an error.

       If program does not contain shader objects of type GL_FRAGMENT_SHADER, an executable will be installed on the vertex, and possibly geometry
       processors, but the results of fragment shader execution will be undefined.

NOTES

       Like buffer and texture objects, the name space for program objects may be shared across a set of contexts, as long as the server sides of
       the contexts share the same address space. If the name space is shared across contexts, any attached objects and the data associated with
       those attached objects are shared as well.

       Applications are responsible for providing the synchronization across API calls when objects are accessed from different execution threads.

ERRORS

       GL_INVALID_VALUE is generated if program is neither 0 nor a value generated by OpenGL.

       GL_INVALID_OPERATION is generated if program is not a program object.

       GL_INVALID_OPERATION is generated if program could not be made part of current state.

       GL_INVALID_OPERATION is generated if transform feedback mode is active.

ASSOCIATED GETS

       glGet() with the argument GL_CURRENT_PROGRAM

       glGetActiveAttrib() with a valid program object and the index of an active attribute variable

       glGetActiveUniform() with a valid program object and the index of an active uniform variable

       glGetAttachedShaders() with a valid program object

       glGetAttribLocation() with a valid program object and the name of an attribute variable

       glGetProgram() with a valid program object and the parameter to be queried

       glGetProgramInfoLog() with a valid program object

       glGetUniform() with a valid program object and the location of a uniform variable

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

       glIsProgram()

SEE ALSO

       glAttachShader(), glBindAttribLocation(), glCompileShader(), glCreateProgram(), glDeleteProgram(), glDetachShader(), glLinkProgram(),
       glUniform(), glValidateProgram(), glVertexAttrib()

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							  GLUSEPROGRAM(3G)