glGetConvolutionFilter
- get current 1D or 2D convolution filter kernel
C SPECIFICATION
void glGetConvolutionFilter(
GLenum target,
GLenum format,
GLenum type,
GLvoid *image )
PARAMETERS
target
The filter to be retrieved.
Must be one of
GL_CONVOLUTION_1D or
GL_CONVOLUTION_2D.
format
Format of the output image.
Must be one of
GL_RED,
GL_GREEN,
GL_BLUE,
GL_ALPHA,
GL_RGB,
GL_BGR,
GL_RGBA,
GL_BGRA,
GL_LUMINANCE, or
GL_LUMINANCE_ALPHA.
type
Data type of components in the output image.
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.
image
Pointer to storage for the output image.
DESCRIPTION
glGetConvolutionFilter returns the current 1D or 2D convolution filter kernel as an image.
The one- or two-dimensional image is placed in image according to the
specifications in format and type.
No pixel transfer operations are performed on this image, but the relevant
pixel storage modes are applied.
Color components that are present in format but not included in the
internal of the filter 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
glGetConvolutionFilter is present only if GL_ARB_imaging is returned when glGetString
is called with an argument of GL_EXTENSIONS.
The current separable 2D filter must be retrieved with
glGetSeparableFilter rather than glGetConvolutionFilter.
ERRORS
GL_INVALID_ENUM is generated if target is not one of the allowable
values.
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 glGetConvolutionFilter 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.
