fglGetSeparableFilter(3G)

NAME
     fglGetSeparableFilter - get separable convolution filter kernel images


FORTRAN SPECIFICATION
     SUBROUTINE fglGetSeparableFilter( INTEGER*4 target,
                                       INTEGER*4 format,
                                       INTEGER*4 type,
                                       CHARACTER*8 row,
                                       CHARACTER*8 column,
                                       CHARACTER*8 span )


PARAMETERS
     target  The separable filter to be retrieved.  Must be GL_SEPARABLE_2D.

     format  Format of the output images.  Must be one of GL_RED, GL_GREEN,
             GL_BLUE, GL_ALPHA, GL_RGB, GL_BGR GL_RGBA, GL_BGRA, GL_ABGR_EXT,
             GL_LUMINANCE, or GL_LUMINANCE_ALPHA.

     type    Data type of components in the output images.  Symbolic constants
             GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP, GL_UNSIGNED_SHORT,
             GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT,
             GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
             GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV,
             GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
             GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
             GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
             GL_UNSIGNED_INT_10_10_10_2, and GL_UNSIGNED_INT_2_10_10_10_REV
             are accepted.

     row     Pointer to storage for the row filter image.

     column  Pointer to storage for the column filter image.

     span    Pointer to storage for the span filter image (currently unused).

DESCRIPTION
     fglGetSeparableFilter returns the two one-dimensional filter kernel
     images for the current separable 2D convolution filter.  The row image is
     placed in row and the column image is placed in column according to the
     specifications in format and type.  (In the current implementation, span
     is not affected in any way.)  No pixel transfer operations are performed
     on the images, but the relevant pixel storage modes are applied.

     Color components that are present in format but not included in the
     internal format of the filters are returned as zero.  The assignments of
     internal color components to the components of format are as follows:


                     ________________________________________
                     Internal Component   Resulting Component
                    _________________________________________
                     Red                  Red
                     Green                Green
                     Blue                 Blue
                     Alpha                Alpha
                     Luminance            Red
                     Intensity            Red
                     ________________________________________


NOTES
     fglGetSeparableFilter is present only if GL_ARB_imaging is returned when
     fglGetString is called with an argument of GL_EXTENSIONS.

     GL_ABGR_EXT is valid only if the EXT_abgr extension is supported.

     Non-separable 2D filters must be retrieved with fglGetConvolutionFilter.

ERRORS
     GL_INVALID_ENUM is generated if target is not GL_SEPARABLE_2D.

     GL_INVALID_ENUM is generated if format is not one of the allowable
     values.

     GL_INVALID_ENUM is generated if type is not one of the allowable values.

     GL_INVALID_OPERATION is generated if fglGetSeparableFilter is executed
     between the execution of fglBegin and the corresponding execution of
     fglEnd.

     GL_INVALID_OPERATION is generated if type is one of
     GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
     GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and format is not
     GL_RGB.

     GL_INVALID_OPERATION is generated if type is one of
     GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
     GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
     GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
     GL_UNSIGNED_INT_10_10_10_2, or GL_UNSIGNED_INT_2_10_10_10_REV and format
     is not GL_RGBA, GL_BGRA or GL_ABGR_EXT.

ASSOCIATED GETS
     fglGetConvolutionParameter


SEE ALSO
     fglGetConvolutionFilter, fglConvolutionParameter, fglSeparableFilter2D