glConvolutionParameter(3G) OpenGL Reference glConvolutionParameter(3G)
glConvolutionParameterf, glConvolutionParameteri,
glConvolutionParameterfv, glConvolutionParameteriv - 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 is GL_CONVOLUTION_BORDER_MODE, params
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 is GL_CONVOLUTION_FILTER_SCALE), or biasing
(when pname is GL_CONVOLUTION_FILTER_BIAS) a convolution filter
kernel or setting the constant border color (when pname is
GL_CONVOLUTION_BORDER_COLOR.
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glConvolutionParameter(3G) OpenGL Reference glConvolutionParameter(3G)
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 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 [Toc] [Back]
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.
GL_CONSTANT_BORDER [Toc] [Back]
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 [Toc] [Back]
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 GL_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.
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glConvolutionParameter(3G) OpenGL Reference glConvolutionParameter(3G)
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.
glGetConvolutionParameter
glConvolutionFilter1D, glConvolutionFilter2D, glSeparableFilter2D,
glGetConvolutionParameter
PPPPaaaaggggeeee 3333 [ Back ]
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