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GLCOPYCONVOLUTIONFILTER1D(3G)			 GLCOPYCONVOLUTIONFILTER1D(3G)

NAME
       glCopyConvolutionFilter1D - copy pixels into a one-dimensional convolu‐
       tion filter

C SPECIFICATION
       void glCopyConvolutionFilter1D( GLenum target,
				       GLenum internalformat,
				       GLint x,
				       GLint y,
				       GLsizei width )

PARAMETERS
       target	       Must be GL_CONVOLUTION_1D.

       internalformat  The internal  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.

       x, y	       The window space coordinates of the lower-left  coordi‐
		       nate of the pixel array to copy.

       width	       The width of the pixel array to copy.

DESCRIPTION
       glCopyConvolutionFilter1D  defines a one-dimensional convolution filter
       kernel with pixels from the current GL_READ_BUFFER  (rather  than  from
       main memory, as is the case for glConvolutionFilter1D).

       The  screen-aligned  pixel  rectangle with lower-left corner at (x, y),
       width width and height 1 is used to define the convolution filter.   If
       any pixels within this region are outside the window that is associated
       with the GL context, the values obtained for  those  pixels  are	 unde‐
       fined.

       The  pixels  in	the rectangle are processed exactly as if glReadPixels
       had been called with format set to RGBA, but  the  process  stops  just
       before  final  conversion.  The R, G, B, and A components of each pixel
       are next scaled by the four 1D  GL_CONVOLUTION_FILTER_SCALE  parameters
       and  biased by the four 1D GL_CONVOLUTION_FILTER_BIAS parameters.  (The
       scale and bias parameters are set by glConvolutionParameter  using  the
       GL_CONVOLUTION_1D  target and the names GL_CONVOLUTION_FILTER_SCALE and
       GL_CONVOLUTION_FILTER_BIAS.  The parameters 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  specified by internalfor‐
       mat.  This conversion simply maps the component values of the pixel (R,
       G, B, and A) to the values included in the internal  (red, green, blue,
       alpha, luminance, and intensity).  The mapping is as follows:

       ────────────────────────────────────────────────────────────────────────
       Internal Format	    Red	  Green	  Blue	 Alpha	 Luminance   Intensity
       ────────────────────────────────────────────────────────────────────────
       GL_ALPHA					   A
       GL_LUMINANCE				   R
       GL_LUMINANCE_ALPHA		   A	   R
       GL_INTENSITY							 R
       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

       Pixel  ordering	is  such that lower x screen coordinates correspond to
       lower i filter image coordinates.

       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
       glCopyConvolutionFilter1D 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 target is not GL_CONVOLUTION_1D.

       GL_INVALID_ENUM is generated if internalformat is not one of the allow‐
       able values.

       GL_INVALID_VALUE	 is  generated	if  width is less than zero or greater
       than the maximum supported value.   This	 value	may  be	 queried  with
       glGetConvolutionParameter   using  target  GL_CONVOLUTION_1D  and  name
       GL_MAX_CONVOLUTION_WIDTH.

       GL_INVALID_OPERATION is generated if glCopyConvolutionFilter1D is  exe‐
       cuted  between the execution of glBegin and the corresponding execution
       of glEnd.

ASSOCIATED GETS
       glGetConvolutionParameter, glGetConvolutionFilter

SEE ALSO
       glConvolutionFilter1D(3G),		   glConvolutionParameter(3G),
       glPixelTransfer(3G)

						 GLCOPYCONVOLUTIONFILTER1D(3G)
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