fglConvolutionParameterEXT(3G) OpenGL Reference
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.
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fglConvolutionParameterEXT(3G) OpenGL Reference
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
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fglConvolutionParameterEXT(3G) OpenGL Reference
SEE ALSO
fglConvolutionFilter1DEXT, fglConvolutionFilter2DEXT,
fglSeparableFilter2DEXT, fglGetConvolutionParameterEXT.
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