The separable filter to be retrieved.
Must be
GL_SEPARABLE_2D.
format
Format of the output images.
Must be one of
GL_RED,
GL_GREEN,
GL_BLUE,
GL_ALPHA,
GL_RGB,
GL_BGRGL_RGBA,
GL_BGRA,
GL_LUMINANCE, or
GL_LUMINANCE_ALPHA.
type
Data type of components in the output images.
Symbolic constants
GL_UNSIGNED_BYTE,
GL_BYTE,
GL_BITMAP,
GL_UNSIGNED_SHORT,
GL_SHORT,
GL_UNSIGNED_INT,
GL_INT,
GL_FLOAT,
GL_UNSIGNED_BYTE_3_3_2,
GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5,
GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and
GL_UNSIGNED_INT_2_10_10_10_REV
are accepted.
row
Pointer to storage for the row filter image.
column
Pointer to storage for the column filter image.
span
Pointer to storage for the span filter image (currently unused).
DESCRIPTION
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.
Color components that are present in format but not included in the
internal 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
NOTES
glGetSeparableFilter is present only if GL_ARB_imaging is returned when glGetString
is called with an argument of GL_EXTENSIONS.
Non-separable 2D filters must be retrieved with glGetConvolutionFilter.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_SEPARABLE_2D.
GL_INVALID_ENUM is generated if format is not one of the allowable
values.
GL_INVALID_ENUM is generated if type is not one of the allowable
values.
GL_INVALID_OPERATION is generated if glGetSeparableFilter is executed
between the execution of glBegin and the corresponding
execution of glEnd.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_BYTE_3_3_2,
GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, or
GL_UNSIGNED_SHORT_5_6_5_REV
and format is not GL_RGB.
GL_INVALID_OPERATION is generated if type is one of
GL_UNSIGNED_SHORT_4_4_4_4,
GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1,
GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8,
GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, or
GL_UNSIGNED_INT_2_10_10_10_REV
and format is neither GL_RGBA nor GL_BGRA.