glConvolutionParameter — set convolution parameters
void glConvolutionParameterf( | GLenum | target, |
GLenum | pname, | |
GLfloat | params) ; |
void glConvolutionParameteri( | GLenum | target, |
GLenum | pname, | |
GLint | params) ; |
target
The target for the convolution parameter.
Must be one of
GL_CONVOLUTION_1D
,
GL_CONVOLUTION_2D
, or
GL_SEPARABLE_2D
.
pname
The parameter to be set.
Must be
GL_CONVOLUTION_BORDER_MODE
.
params
The parameter value.
Must be one of
GL_REDUCE
, GL_CONSTANT_BORDER
, GL_REPLICATE_BORDER
.
void glConvolutionParameterfv( | GLenum | target, |
GLenum | pname, | |
const GLfloat * | params) ; |
void glConvolutionParameteriv( | GLenum | target, |
GLenum | pname, | |
const GLint * | params) ; |
target
The target for the convolution parameter.
Must be one of
GL_CONVOLUTION_1D
,
GL_CONVOLUTION_2D
, or
GL_SEPARABLE_2D
.
pname
The parameter to be set.
Must be one of
GL_CONVOLUTION_BORDER_MODE
,
GL_CONVOLUTION_BORDER_COLOR
,
GL_CONVOLUTION_FILTER_SCALE
, or
GL_CONVOLUTION_FILTER_BIAS
.
params
The parameter value.
If pname
v is GL_CONVOLUTION_BORDER_MODE
, params
v must be one of
GL_REDUCE
, GL_CONSTANT_BORDER
, or GL_REPLICATE_BORDER
.
Otherwise, must be a vector of four values (for red, green, blue, and alpha,
respectively) to be used for
scaling (when pname
v is GL_CONVOLUTION_FILTER_SCALE
), or
biasing (when pname
v is GL_CONVOLUTION_FILTER_BIAS
) a convolution
filter kernel or setting the constant border color (when pname
v is
GL_CONVOLUTION_BORDER_COLOR
.
glConvolutionParameter
sets the value of a convolution parameter.
target
selects the convolution filter to be affected:
GL_CONVOLUTION_1D
,
GL_CONVOLUTION_2D
, or
GL_SEPARABLE_2D
for the 1D, 2D, or separable 2D filter, respectively.
pname
selects the parameter to be changed.
GL_CONVOLUTION_FILTER_SCALE
and GL_CONVOLUTION_FILTER_BIAS
affect the definition of the convolution filter kernel; see
glConvolutionFilter1D, glConvolutionFilter2D, and
glSeparableFilter2D for details.
In these cases, params
v is an array of four values to be applied to
red, green, blue, and alpha values, respectively. The initial value for
GL_CONVOLUTION_FILTER_SCALE
is (1, 1, 1, 1), and the initial value
for GL_CONVOLUTION_FILTER_BIAS
is (0, 0, 0, 0).
A pname
value of GL_CONVOLUTION_BORDER_MODE
controls the
convolution border mode. The accepted modes are:
GL_REDUCE
The image resulting from convolution is
smaller than the source image.
If the filter width is
GL_CONSTANT_BORDER
The image resulting from convolution is the same size as the source image, and
processed as if the source image were surrounded by pixels with their color
specified by the GL_CONVOLUTION_BORDER_COLOR
.
GL_REPLICATE_BORDER
The image resulting from convolution is the same size as the source image, and processed as if the outermost pixel on the border of the source image were replicated.
glConvolutionParameter
is present only if ARB_imaging
is returned when glGetString
is called with an argument of GL_EXTENSIONS
.
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, glTexImage1D requires power-of-two image size.
When GL_REDUCE
border mode is in effect,
the source image must be larger than the final power-of-two size
by one less than the size of the 1D filter kernel.
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
and params
is not one of
GL_REDUCE
, GL_CONSTANT_BORDER
, or GL_REPLICATE_BORDER
.
GL_INVALID_OPERATION
is generated if glConvolutionParameter
is executed
between the execution of glBegin and the corresponding
execution of glEnd.
glConvolutionFilter1D, glConvolutionFilter2D, glSeparableFilter2D, glGetConvolutionParameter
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