glGetConvolutionFilter — get current 1D or 2D convolution filter kernel
void glGetConvolutionFilter( | GLenum | target, |
| GLenum | format, | |
| GLenum | type, | |
| GLvoid * | image); |
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.
imagePointer to storage for the output image.
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.
If a non-zero named buffer object is bound to the GL_PIXEL_PACK_BUFFER target
(see glBindBuffer) while a convolution filter is
requested, image is 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 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 |
glGetConvolutionFilter is present only if 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.
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 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.
GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER target and the buffer object's data store is currently mapped.
GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER target and the data would be packed to the buffer
object such that the memory writes required would exceed the data store size.
GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
GL_PIXEL_PACK_BUFFER target and image is not evenly divisible
into the number of bytes needed to store in memory a datum indicated by type.
GL_INVALID_OPERATION is generated if glGetConvolutionFilter is executed
between the execution of glBegin and the corresponding
execution of glEnd.
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/.