glCopyConvolutionFilter2DEXT

NAME

glCopyConvolutionFilter2DEXT - copy pixels into a two-dimensional

C SPECIFICATION

void glCopyConvolutionFilter2DEXT(GLenum target,
                                  GLenum internalformat,
                                  GLint x,
                                  GLint y,
                                  GLsizei width,
                                  GLsizei height)

PARAMETERS

target	Must be GL_CONVOLUTION_2D_EXT.
internalformat	The internal format of the convolution filter kernel. The allowable values are GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_INTENSITY, GL_RGB, and GL_RGBA.
x	The x coordinate of the lower-left coordinate of the pixel array to copy.
y	The y coordinate of the lower-left coordinate of the pixel array to copy.
width	The width of the pixel array to copy.
height	The height of the pixel array to copy.

DESCRIPTION

glCopyConvolutionFilter2DEXT defines a two-dimensional convolution filter kernel with pixels from the current GL_READ_BUFFER (rather than from main memory, as is the case for glConvolutionFilter2DEXT).

The x, y, width, and height correspond to the x, y, width, and height arguments of glReadPixels; they specify the image width and height and the lower-left coordinates in the frame buffer. The image is taken from frame buffer exactly as if these arguments were passed to glReadPixels with argument format set to GL_RGBA, stopping after the final expansion to RGBA. If any pixels defined by the region are outside of the window associated with the GL context, the values obtained for those pixels are undefined. Subsequent processing is identical to that of glConvolutionFilter2DEXT.

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: glCopyConvolutionFilter2DEXT GL_CONVOLUTION_2D_EXT, GL_CONVOLUTION_FILTER_SCALE_EXT, and GL_CONVOLUTION_FILTER_BIAS_EXT are part of the EXT_convolution extension.
EXT_interlace_read: GL_INTERLACE_READ_I3D is part of the EXT_interlace_read extension.

ERRORS

GL_INVALID_ENUM is generated if target is not GL_CONVOLUTION_2D_EXT.

GL_INVALID_ENUM is generated if internalformat is not one of the allowable values.

GL_INVALID_VALUE is generated if width is less than zero or greater than the maximum supported value. This value may be queried with glGetConvolutionParameterEXT using target GL_CONVOLUTION_2D_EXT and name GL_MAX_CONVOLUTION_WIDTH_EXT.

GL_INVALID_VALUE is generated if height is less than zero or greater than the maximum supported value. This value may be queried with glGetConvolutionParameterEXT using target GL_CONVOLUTION_2D_EXT and name GL_MAX_CONVOLUTION_HEIGHT_EXT.

GL_INVALID_OPERATION is generated if glCopyConvolutionFilter2DEXT is executed between the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS

glGetConvolutionParameterEXT
glGetConvolutionFilterEXT