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GLGETCONVOLUTIONFILTER(3G)                                                        GLGETCONVOLUTIONFILTER(3G)



NAME
       glGetConvolutionFilter - get current 1D or 2D convolution filter kernel


C SPECIFICATION
       void glGetConvolutionFilter( GLenum target,
                                    GLenum format,
                                    GLenum type,
                                    GLvoid *image )


PARAMETERS
       target  The filter to be retrieved.  Must be one of GL_CONVOLUTION_1D or GL_CONVOLUTION_2D.

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

       type    Data type of components in the output image.  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.

       image   Pointer to storage for the output image.

DESCRIPTION
       glGetConvolutionFilter returns the current 1D or 2D convolution filter kernel as an image.  The  one-or oneor
       or  two-dimensional  image is placed in image according to the specifications in format and type.  No
       pixel transfer operations are performed on this image, but  the  relevant  pixel  storage  modes  are
       applied.

       Color  components  that  are  present  in  format but not included in the internal  of the filter 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
       glGetConvolutionFilter  is present only if GL_ARB_imaging is returned when glGetString is called with
       an argument of GL_EXTENSIONS.

       The  current  separable  2D  filter  must  be  retrieved  with   glGetSeparableFilter   rather   than
       glGetConvolutionFilter.

ERRORS
       GL_INVALID_ENUM is generated if target is not one of the allowable values.

       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  glGetConvolutionFilter  is executed between the execution of
       glBegin and the corresponding execution of glEnd.

       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 neither GL_RGBA nor GL_BGRA.

ASSOCIATED GETS
       glGetConvolutionParameter

SEE ALSO
       glGetSeparableFilter(3G), glConvolutionParameter(3G), glConvolutionFilter1D(3G), glConvolutionFilter2D(3G)




                                                                                  GLGETCONVOLUTIONFILTER(3G)