glGetConvolutionParameterEXT

NAME

glGetConvolutionParameterfvEXT, glGetConvolutionParameterivEXT - get convolution parameters

C SPECIFICATION

void glGetConvolutionParameterfvEXT(GLenum target,
                                    GLenum pname,
                                    GLfloat *params)
void glGetConvolutionParameterivEXT(GLenum target,
                                    GLenum pname,
                                    GLint *params)

PARAMETERS

target	The filter whose parameters are to be retrieved. Must be one of GL_CONVOLUTION_1D_EXT, GL_CONVOLUTION_2D_EXT, or GL_SEPARABLE_2D_EXT.
pname	The parameter to be retrieved. Must be one of GL_CONVOLUTION_BORDER_MODE_EXT, GL_CONVOLUTION_BORDER_COLOR, GL_CONVOLUTION_FILTER_SCALE_EXT, GL_CONVOLUTION_FILTER_BIAS_EXT, GL_CONVOLUTION_FORMAT_EXT, GL_CONVOLUTION_WIDTH_EXT, GL_CONVOLUTION_HEIGHT_EXT, GL_MAX_CONVOLUTION_WIDTH_EXT, or GL_MAX_CONVOLUTION_HEIGHT_EXT.
params	Pointer to storage for the parameters to be retrieved.

DESCRIPTION

glGetConvolutionParameterEXT retrieves convolution parameters. The target parameter determines which convolution filter is queried. The pname parameter determines which parameter is returned:

GL_CONVOLUTION_BORDER_MODE_EXT: The convolution border mode. See glConvolutionParameterEXT for a list of border modes.
GL_CONVOLUTION_BORDER_COLOR_EXT: The convolution border color. The params parameter must be a pointer to an array of four elements, which receive the RGBA border color.
GL_CONVOLUTION_FILTER_SCALE_EXT: The current filter scale factors. The params parameter must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter scale factors in that order.
GL_CONVOLUTION_FILTER_BIAS_EXT: The current filter bias factors. The params parameter must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter bias terms in that order.
GL_CONVOLUTION_FORMAT_EXT: The current internal format. See glConvolutionFilter1DEXT, glConvolutionFilter2DEXT, and glSeparableFilter2DEXT for lists of allowable formats.
GL_CONVOLUTION_WIDTH_EXT: The current filter image width.
GL_CONVOLUTION_HEIGHT_EXT: The current filter image height.
GL_MAX_CONVOLUTION_WIDTH_EXT: The maximum acceptable filter image width.
GL_MAX_CONVOLUTION_HEIGHT_EXT: The maximum acceptable filter image height.

EXTENSIONS

Some routines and constants for this function are part of an extension, not part of the core GL command set. The following extension names must be present in the string returned by glGetString when called with argument GL_EXTENSIONS to use these routines and constants.

GL_EXT_convolution: glGetConvolutionParameterEXT, GL_CONVOLUTION_1D_EXT, GL_CONVOLUTION_2D_EXT, GL_SEPARABLE_2D_EXT, GL_CONVOLUTION_BORDER_MODE_EXT, GL_CONVOLUTION_FILTER_SCALE_EXT, GL_CONVOLUTION_FILTER_BIAS_EXT, GL_CONVOLUTION_FORMAT_EXT, GL_CONVOLUTION_WIDTH_EXT, GL_CONVOLUTION_HEIGHT_EXT, GL_MAX_CONVOLUTION_WIDTH_EXT, and GL_MAX_CONVOLUTION_HEIGHT_EXT are part of the EXT_convolution extension.

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 target is GL_CONVOLUTION_1D_EXT and pname is GL_CONVOLUTION_HEIGHT_EXT or GL_MAX_CONVOLUTION_HEIGHT_EXT.

GL_INVALID_OPERATION is generated if glGetConvolutionParameterEXT is executed between the execution of glBegin and the corresponding execution of glEnd.