- return texture environment parameters



C SPECIFICATION


PARAMETERS

       _param1  Specifies   a   texture   environment.   Must  be
                GL_TEXTURE_ENV.

       _param2  Specifies the symbolic name of a texture environ-
                ment     parameter.     Accepted    values    are
                GL_TEXTURE_ENV_MODE and GL_TEXTURE_ENV_COLOR.

       _param3  Returns the requested data.


DESCRIPTION

       glGetTexEnv returns in _param3 selected values of  a  tex-
       ture   environment   that  was  specified  with  glTexEnv.
       _param1 specifies a texture environment.  Currently,  only
       one   texture   environment   is  defined  and  supported:
       GL_TEXTURE_ENV.

       _param2 names a specific texture environment parameter, as
       follows:

       GL_TEXTURE_ENV_MODE
                 _param3  returns the single-valued texture envi-
                 ronment mode, a symbolic constant.  The  initial
                 value is GL_MODULATE.

       GL_TEXTURE_ENV_COLOR
                 _param3  returns  four integer or floating-point
                 values that are the texture  environment  color.
                 Integer  values,  when  requested,  are linearly
                 mapped from the internal  floating-point  repre-
                 sentation  such  that 1.0 maps to the most posi-
                 tive representable integer, and -1.0 maps to the
                 most negative representable integer. The initial
                 value is (0, 0, 0, 0).


NOTES

       If an error is generated, no change is made  to  the  con-
       tents of _param3.

       When   the  GL_ARB_multitexture  extension  is  supported,
       glGetTexEnv returns the texture environment parameters for
       the active texture unit.


ERRORS

       GL_INVALID_ENUM  is generated if _param1 or _param2 is not
       an accepted value.

       GL_INVALID_OPERATION is generated if glGetTexEnv  is  exe-