fglConvolutionParameterEXT(3G)

NAME
     fglConvolutionParameterfEXT, fglConvolutionParameteriEXT,
     fglConvolutionParameterfvEXT, fglConvolutionParameterivEXT - set
     convolution parameters


FORTRAN SPECIFICATION
     SUBROUTINE fglConvolutionParameterfEXT( INTEGER*4 target,
                                             INTEGER*4 pname,
                                             REAL*4 params )
     SUBROUTINE fglConvolutionParameteriEXT( INTEGER*4 target,
                                             INTEGER*4 pname,
                                             INTEGER*4 params )




PARAMETERS
     target  The target for the convolution parameter.  Must be one of
             GL_CONVOLUTION_1D_EXT, GL_CONVOLUTION_2D_EXT, or
             GL_SEPARABLE_2D_EXT.

     pname   The parameter to be set.  Must be GL_CONVOLUTION_BORDER_MODE_EXT.

     params  The parameter value.  Must be GL_REDUCE_EXT.



FORTRAN SPECIFICATION
     SUBROUTINE fglConvolutionParameterfvEXT( INTEGER*4 target,
                                              INTEGER*4 pname,
                                              CHARACTER*8 params )
     SUBROUTINE fglConvolutionParameterivEXT( INTEGER*4 target,
                                              INTEGER*4 pname,
                                              CHARACTER*8 params )




PARAMETERS
     target
          The target for the convolution parameter.  Must be one of
          GL_CONVOLUTION_1D_EXT, GL_CONVOLUTION_2D_EXT, or
          GL_SEPARABLE_2D_EXT.

     pname
          The parameter to be set.  Must be one of
          GL_CONVOLUTION_BORDER_MODE_EXT, GL_CONVOLUTION_FILTER_SCALE_EXT, or
          GL_CONVOLUTION_FILTER_BIAS_EXT.

     params
          The parameter value.  Must be GL_REDUCE_EXT if pname is
          GL_CONVOLUTION_BORDER_MODE_EXT.  Otherwise, must be a vector of four
          values (for red, green, blue, and alpha, respectively) to be used
          for scaling (when pname is GL_CONVOLUTION_FILTER_SCALE_EXT) or for
          biasing (when pname is GL_CONVOLUTION_FILTER_BIAS_EXT) a convolution
          filter kernel.
DESCRIPTION
     fglConvolutionParameterEXT sets the value of a convolution parameter.

     target selects the convolution filter to be affected:
     GL_CONVOLUTION_1D_EXT, GL_CONVOLUTION_2D_EXT, or GL_SEPARABLE_2D_EXT for
     the 1D, 2D, or separable 2D filter, respectively.

     pname selects the parameter to be changed.
     GL_CONVOLUTION_FILTER_SCALE_EXT and GL_CONVOLUTION_FILTER_BIAS_EXT affect
     the definition of the convolution filter kernel; see
     fglConvolutionFilter1DEXT, fglConvolutionFilter2DEXT, and
     fglSeparableFilter2DEXT for details.  In these cases, params is an array
     of four values to be applied to red, green, blue, and alpha values
     respectively.

     A pname value of GL_CONVOLUTION_BORDER_MODE_EXT controls the convolution
     border mode.  Currently the only acceptable parameter value is
     GL_REDUCE_EXT.  When this mode is in effect, the image resulting from
     convolution is smaller than the source image.  If the filter width is Wf
     and height is Hf, and the source image width is Ws and height is Hs, then
     the convolved image width will be Ws-Wf+1 and height will be Hs-Hf+1.
     (If this reduction would generate an image with zero or negative width
     and/or height, the output is simply null, with no error generated.)  The
     coordinates of the image resulting from convolution are zero through Ws-
     Wf in width and zero through Hs-Hf in height.

NOTES
     In cases where errors can result from the specification of invalid image
     dimensions, it is the dimensions after convolution that are tested, not
     the dimensions of the source image.  For example, fglTexImage1D requires
     power-of-two image size.  When REDUCE_EXT border mode is in effect
     (currently this is always true), the source image must be larger than the
     final power-of-two size by one less than the size of the 1D filter
     kernel.

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

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

     GL_INVALID_ENUM is generated if pname is GL_CONVOLUTION_BORDER_MODE_EXT
     and params is not GL_REDUCE_EXT.

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

ASSOCIATED GETS
     fglGetConvolutionParameterEXT

SEE ALSO
     fglConvolutionFilter1DEXT, fglConvolutionFilter2DEXT,
     fglSeparableFilter2DEXT, fglGetConvolutionParameterEXT.