glLightEnv(3G)		       OpenGL Reference			glLightEnv(3G)

NAME    [Toc]    [Back]

     glLightEnviSGIX - specify fragment	lighting environment

C SPECIFICATION    [Toc]    [Back]

     void glLightEnviSGIX( GLenum pname,
			   GLint param )

PARAMETERS    [Toc]    [Back]

     pname  Must be GL_LIGHT_ENV_MODE_SGIX

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

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     glLightEnv	is part	of the GL_SGIX_fragment_lighting extension. glLightEnv
     is	present	only if	GL_SGIX_fragment_lighting is returned when glGetString
     is	called with GL_EXTENSIONS as its argument.

ERRORS    [Toc]    [Back]

     GL_INVALID_OPERATION is generated if glLightEnv is	executed between the
     execution of glBegin and the corresponding	execution of glEnd.
     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    [Toc]    [Back]

     glGet 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    [Toc]    [Back]

     glGetString, glFragmentLight


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