fglLightEnv(3G)

NAME
     fglLightEnviSGIX - specify fragment lighting environment


FORTRAN SPECIFICATION
     SUBROUTINE fglLightEnviSGIX( INTEGER*4 pname,
                                  INTEGER*4 param )


PARAMETERS
     pname  Must be GL_LIGHT_ENV_MODE_SGIX

     param  Can be one of three values: GL_REPLACE, GL_MODULATE, or GL_ADD

DESCRIPTION
     GL_LIGHT_ENV_MODE_SGIX specifies how the color computed by fragment
     lighting calculations is combined with the post-texturing fragment color.

     GL_REPLACE          The lighting color replaces the fragment color

     GL_MODULATE         Each (R,G,B,A) component of the fragment color is
                         multiplied by the corresponding component of the
                         lighting color

     GL_ADD              The lighting color is added to the fragment color

     Initially GL_LIGHT_ENV_MODE_SGIX is set to GL_REPLACE.

NOTES
     fglLightEnv is part of the GL_SGIX_fragment_lighting extension.
     fglLightEnv is present only if GL_SGIX_fragment_lighting is returned when
     fglGetString is called with GL_EXTENSIONS as its argument.

ERRORS
     GL_INVALID_OPERATION is generated if fglLightEnv is executed between the
     execution of fglBegin and the corresponding execution of fglEnd.
     GL_INVALID_ENUM is generated if pname is not GL_LIGHT_ENV_MODE_SGIX, or
     param is not one of GL_REPLACE, GL_MODULATE, or GL_ADD.

ASSOCIATED GETS
     fglGet with an argument of GL_LIGHT_ENV_MODE_SGIX


MACHINE DEPENDENCIES
     The SGIX_fragment_lighting extension is supported only on Octane2 VPro
     systems.


SEE ALSO
     fglGetString, fglFragmentLight