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BUGLE-SHOWEXTENSION(7)         Bugle user manual        BUGLE-SHOWEXTENSION(7)


NAME

       bugle-showextensions - show which extensions are used by an OpenGL
       application


SYNOPSIS

       filterset showextensions


DESCRIPTION

       The showextensions filter-set can be used to determine what version of
       OpenGL and which extensions are used by a particular application. It
       can be used to check that an application does not accidentally depend
       on an OpenGL version that is not targetted. The most common error is
       calling a core OpenGL function (for a recent version of OpenGL) when
       one intended to use an older and more widely supported extension.

       Note that it can only report what is used, not what is required, which
       may be different if the application uses certain features only after
       detecting them (but see bugle-extoverride(7) for a way to handle this).
       It also only tests the run-time usage; the compile-time usage may be
       different.

       Two methods are used for detection: the functions called and the
       enumerants passed to functions. The former is quite reliable, since
       different entry points are used for the core and extension versions of
       the same function. The latter is necessary to detect extensions such as
       GL_SGIS_generate_mipmap which do not introduce new function calls, but
       it is less reliable as many enumerants share values. Some extensions
       are not detected at all: GL_ARB_texture_non_power_of_two does not
       introduce any tokens or functions, and some promoted extensions (such
       as GL_ARB_pixel_buffer_object) have additional semantics to their
       predecessors but again introduce no new tokens or functions.


OUTPUT

       A typical output is the following:

           Min GL version: GL_VERSION_1_5
           Min GLX version: GLX_VERSION_1_2
           Used extensions: GL_ARB_shader_objects GL_ARB_vertex_shader

       This indicates that the application used OpenGL 1.5 and GLX 1.2 (and
       possibly some extensions that are incorporated into OpenGL 1.5), as
       well as the extensions listed.


BUGS

       o   Detection is not completely reliable, as described above.

       o   Sometimes extensions are listed even though they are already part
           of the core version listed.

       o   It is assumed that OpenGL 1.1 and GLX 1.2 are used; there is no way
           to detect whether an application would work on OpenGL 1.0 or GLX
           1.1.


AUTHOR

       bugle is written and maintained by Bruce Merry.


SEE ALSO

       bugle(3), bugle-extoverride(7)

BUGLE 0.0.20091026               October 2007           BUGLE-SHOWEXTENSION(7)

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