glGetSeparableFilter

glGetSeparableFilter: man2/glGetSeparableFilter.xml

glGetSeparableFilter returns the two one-dimensional filter kernel images for the current separable 2D convolution filter. The row image is placed in row and the column image is placed in column according to the specifications in format and type. (In the current implementation, span is not affected in any way.) No pixel transfer operations are performed on the images, but the relevant pixel storage modes are applied. If a non-zero named buffer object is bound to the GL_PIXEL_PACK_BUFFER target (see glBindBuffer ) while a separable convolution filter is requested, row, column, and span are treated as a byte offset into the buffer object's data store. Color components that are present in format but not included in the internal format of the filters are returned as zero. The assignments of internal color components to the components of format are as follows: Internal Component Resulting Component Red Red Green Green Blue Blue Alpha Alpha Luminance Red Intensity Red

glGetSeparableFilter is present only if ARB_imaging is returned when glGetString is called with an argument of GL_EXTENSIONS. Non-separable 2D filters must be retrieved with glGetConvolutionFilter.