1991-2006
Silicon Graphics, Inc.
glGetConvolutionParameter
3G

# glGetConvolutionParameter

get convolution parameters

## C Specification

                    void glGetConvolutionParameterfv
                    GLenum target
                    GLenum pname
                    GLfloat * params

                    void glGetConvolutionParameteriv
                    GLenum target
                    GLenum pname
                    GLint * params

## Parameters

`target`

  The filter whose parameters are to be retrieved. Must be one of `GL_CONVOLUTION_1D`, `GL_CONVOLUTION_2D`, or `GL_SEPARABLE_2D`.

`pname`

  The parameter to be retrieved. Must be one of `GL_CONVOLUTION_BORDER_MODE`, `GL_CONVOLUTION_BORDER_COLOR`, `GL_CONVOLUTION_FILTER_SCALE`, `GL_CONVOLUTION_FILTER_BIAS`, `GL_CONVOLUTION_FORMAT`, `GL_CONVOLUTION_WIDTH`, `GL_CONVOLUTION_HEIGHT`, `GL_MAX_CONVOLUTION_WIDTH`, or `GL_MAX_CONVOLUTION_HEIGHT`.

`params`

  Pointer to storage for the parameters to be retrieved.

## Description

`glGetConvolutionParameter` retrieves convolution parameters. `target` determines which convolution filter is queried. `pname` determines which parameter is returned:

`GL_CONVOLUTION_BORDER_MODE`

  The convolution border mode. See glConvolutionParameter for a list of border modes.

`GL_CONVOLUTION_BORDER_COLOR`

  The current convolution border color. `params` must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha border colors.

`GL_CONVOLUTION_FILTER_SCALE`

  The current filter scale factors. `params` 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`

  The current filter bias factors. `params` 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`

  The current internal format. See glConvolutionFilter1D, glConvolutionFilter2D, and glSeparableFilter2D for lists of allowable formats.

`GL_CONVOLUTION_WIDTH`

  The current filter image width.

`GL_CONVOLUTION_HEIGHT`

  The current filter image height.

`GL_MAX_CONVOLUTION_WIDTH`

  The maximum acceptable filter image width.

`GL_MAX_CONVOLUTION_HEIGHT`

  The maximum acceptable filter image height.

## 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` and `pname` is `GL_CONVOLUTION_HEIGHT` or `GL_MAX_CONVOLUTION_HEIGHT`.

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

## See Also

glGetConvolutionFilter, glGetSeparableFilter, glConvolutionParameter

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.