glGetConvolutionFilter(3gl)

1GLGETCONVOLUTIONFILTER(3G)                          GLGETCONVOLUTIONFILTER(3G)
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NAME

6       glGetConvolutionFilter - get current 1D or 2D convolution filter kernel
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C SPECIFICATION

10       void glGetConvolutionFilter( GLenum target,
11                                    GLenum format,
12                                    GLenum type,
13                                    GLvoid *image )
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PARAMETERS

17       target  The  filter  to be retrieved.  Must be one of GL_CONVOLUTION_1D
18               or GL_CONVOLUTION_2D.
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20       format  Format of the output image.  Must be one of  GL_RED,  GL_GREEN,
21               GL_BLUE,    GL_ALPHA,   GL_RGB,   GL_BGR,   GL_RGBA,   GL_BGRA,
22               GL_LUMINANCE, or GL_LUMINANCE_ALPHA.
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24       type    Data type of components in the  output  image.   Symbolic  con‐
25               stants GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP, GL_UNSIGNED_SHORT,
26               GL_SHORT,       GL_UNSIGNED_INT,       GL_INT,        GL_FLOAT,
27               GL_UNSIGNED_BYTE_3_3_2,             GL_UNSIGNED_BYTE_2_3_3_REV,
28               GL_UNSIGNED_SHORT_5_6_5,           GL_UNSIGNED_SHORT_5_6_5_REV,
29               GL_UNSIGNED_SHORT_4_4_4_4,       GL_UNSIGNED_SHORT_4_4_4_4_REV,
30               GL_UNSIGNED_SHORT_5_5_5_1,       GL_UNSIGNED_SHORT_1_5_5_5_REV,
31               GL_UNSIGNED_INT_8_8_8_8,           GL_UNSIGNED_INT_8_8_8_8_REV,
32               GL_UNSIGNED_INT_10_10_10_2, and  GL_UNSIGNED_INT_2_10_10_10_REV
33               are accepted.
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35       image   Pointer to storage for the output image.
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DESCRIPTION

38       glGetConvolutionFilter  returns the current 1D or 2D convolution filter
39       kernel as an image.  The one- or two-dimensional  image  is  placed  in
40       image  according  to  the  specifications in format and type.  No pixel
41       transfer operations are performed on this image, but the relevant pixel
42       storage modes are applied.
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44       Color  components  that  are  present in format but not included in the
45       internal  of the filter are  returned  as  zero.   The  assignments  of
46       internal color components to the components of format are as follows.
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48                      ─────────────────────────────────────────
49                      Internal Component   Resulting Component
50                      ─────────────────────────────────────────
51                      Red                  Red
52                      Green                Green
53                      Blue                 Blue
54                      Alpha                Alpha
55                      Luminance            Red
56                      Intensity            Red
57                      ─────────────────────────────────────────
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NOTES

60       glGetConvolutionFilter  is  present  only if GL_ARB_imaging is returned
61       when glGetString is called with an argument of GL_EXTENSIONS.
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63       The   current   separable   2D   filter   must   be   retrieved    with
64       glGetSeparableFilter rather than glGetConvolutionFilter.
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ERRORS

67       GL_INVALID_ENUM is generated if target is not one of the allowable val‐
68       ues.
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70       GL_INVALID_ENUM is generated if format is not one of the allowable val‐
71       ues.
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73       GL_INVALID_ENUM  is  generated if type is not one of the allowable val‐
74       ues.
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76       GL_INVALID_OPERATION is generated if glGetConvolutionFilter is executed
77       between  the  execution  of  glBegin and the corresponding execution of
78       glEnd.
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80       GL_INVALID_OPERATION   is    generated    if    type    is    one    of
81       GL_UNSIGNED_BYTE_3_3_2,                     GL_UNSIGNED_BYTE_2_3_3_REV,
82       GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and  format  is
83       not GL_RGB.
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85       GL_INVALID_OPERATION    is    generated    if    type    is    one   of
86       GL_UNSIGNED_SHORT_4_4_4_4,               GL_UNSIGNED_SHORT_4_4_4_4_REV,
87       GL_UNSIGNED_SHORT_5_5_5_1,               GL_UNSIGNED_SHORT_1_5_5_5_REV,
88       GL_UNSIGNED_INT_8_8_8_8,                   GL_UNSIGNED_INT_8_8_8_8_REV,
89       GL_UNSIGNED_INT_10_10_10_2,  or GL_UNSIGNED_INT_2_10_10_10_REV and for‐
90       mat is neither GL_RGBA nor GL_BGRA.
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ASSOCIATED GETS

93       glGetConvolutionParameter
94