C SPECIFICATION
void GLAPIENTRY glSeparableFilter2D( GLenum targe )
PARAMETERS
targe Must be GL_SEPARABLE_2D.
_param2
The internal format of the convolution filter kernel. The
allowable values are GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12,
GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE8,
GL_LUMINANCE12, GL_LUMINANCE16, GL_LUMINANCE_ALPHA,
GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2,
GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4,
GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_INTENSITY,
GL_INTENSITY4, GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16,
GL_R3_G3_B2, GL_RGB, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10,
GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1,
GL_RGBA8, GL_RGB10_A2, GL_RGBA12, or GL_RGBA16.
_param3
The number of elements in the pixel array referenced by _param7.
(This is the width of the separable filter kernel.)
_param4
The number of elements in the pixel array referenced by _param8.
(This is the height of the separable filter kernel.)
_param5
The format of the pixel data in _param7 and _param8. The allow-
able values are GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB,
GL_BGR, GL_RGBA, GL_BGRA, GL_INTENSITY, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA.
_param6
The type of the pixel data in _param7 and _param8. 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.
_param7
Pointer to a one-dimensional array of pixel data that is pro-
cessed to build the row filter kernel.
scaled by the four separable 2D GL_CONVOLUTION_FILTER_SCALE parameters
and biased by the four separable 2D GL_CONVOLUTION_FILTER_BIAS parame-
ters. (The scale and bias parameters are set by glConvolutionParameter
using the GL_SEPARABLE_2D target and the names
GL_CONVOLUTION_FILTER_SCALE and GL_CONVOLUTION_FILTER_BIAS. The param-
eters themselves are vectors of four values that are applied to red,
green, blue, and alpha, in that order.) The R, G, B, and A values are
not clamped to [0,1] at any time during this process.
Each pixel is then converted to the internal format specified by
_param2. This conversion simply maps the component values of the pixel
(R, G, B, and A) to the values included in the internal format (red,
green, blue, alpha, luminance, and intensity). The mapping is as fol-
lows:
GL_RGB R G B
GL_RGBA R G B A
------------------------------------------------------------------------
The red, green, blue, alpha, luminance, and/or intensity components of
the resulting pixels are stored in floating-point rather than integer
format. They form two one-dimensional filter kernel images. The row
image is indexed by coordinate i starting at zero and increasing from
left to right. Each location in the row image is derived from element
i of _param7. The column image is indexed by coordinate j starting at
zero and increasing from bottom to top. Each location in the column
image is derived from element j of _param8.
Note that after a convolution is performed, the resulting color compo-
nents are also scaled by their corresponding
GL_POST_CONVOLUTION_c_SCALE parameters and biased by their correspond-
ing GL_POST_CONVOLUTION_c_BIAS parameters (where c takes on the values
RED, GREEN, BLUE, and ALPHA). These parameters are set by
glPixelTransfer.
NOTES
glSeparableFilter2D is present only if GL_ARB_imaging is returned when
glGetString is called with an argument of GL_EXTENSIONS.
ERRORS
GL_INVALID_ENUM is generated if targe is not GL_SEPARABLE_2D.
GL_INVALID_ENUM is generated if _param2 is not one of the allowable
values.
GL_INVALID_VALUE is generated if _param3 is less than zero or greater
than the maximum supported value. This value may be queried with
glGetConvolutionParameter using target GL_SEPARABLE_2D and name
GL_MAX_CONVOLUTION_WIDTH.
GL_INVALID_VALUE is generated if _param4 is less than zero or greater
than the maximum supported value. This value may be queried with
glGetConvolutionParameter using target GL_SEPARABLE_2D and name
GL_MAX_CONVOLUTION_HEIGHT.
GL_INVALID_ENUM is generated if _param5 is not one of the allowable
values.
GL_INVALID_ENUM is generated if _param6 is not one of the allowable
values.
GL_INVALID_OPERATION is generated if glSeparableFilter2D is executed
between the execution of glBegin and the corresponding execution of
glEnd.
GL_INVALID_OPERATION is generated if _param4 is one of
SEE ALSO
glConvolutionFilter1D, glConvolutionFilter2D, glConvolutionParameter,
glPixelTransfer
GLSEPARABLEFILTER2D(3G)
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