glConvolutionFilter1DEXT(3G)   OpenGL Reference	  glConvolutionFilter1DEXT(3G)



NAME
     glConvolutionFilter1DEXT -	define a one-dimensional convolution filter


C SPECIFICATION
     void glConvolutionFilter1DEXT( GLenum target,
				    GLenum internalformat,
				    GLsizei width,
				    GLenum format,
				    GLenum type,
				    const GLvoid *image	)


PARAMETERS
     target	     Must be GL_CONVOLUTION_1D_EXT.

     internalformat  The internal format of the	convolution filter kernel.
		     The allowable values are GL_LUMINANCE,
		     GL_LUMINANCE_ALPHA, GL_INTENSITY_EXT, GL_RGB, and
		     GL_RGBA.

     width	     The width of the pixel array referenced by	image.

     format	     The format	of the pixel data in image.  The allowable
		     values are	GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_RGB,
		     GL_RGBA, and GL_ABGR_EXT.

     type	     The type of the pixel data	in image.  The allowable
		     values are	GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT,
		     GL_SHORT, GL_UNSIGNED_INT,	GL_INT,	GL_FLOAT,
		     GL_UNSIGNED_BYTE_3_3_2_EXT,
		     GL_UNSIGNED_SHORT_4_4_4_4_EXT,
		     GL_UNSIGNED_SHORT_5_5_5_1_EXT,
		     GL_UNSIGNED_INT_8_8_8_8_EXT, and
		     GL_UNSIGNED_INT_10_10_10_2_EXT.

     image	     Pointer to	a one-dimensional array	of pixel data that is
		     processed to build	the convolution	filter kernel.

DESCRIPTION
     glConvolutionFilter1DEXT builds a one-dimensional convolution filter
     kernel from an array of pixels.

     The pixel array specified by width, format, type, and image is extracted
     from memory and processed just as if glDrawPixels were called, but
     processing	stops after the	final expansion	to RGBA	is completed.

     The R, G, B, and A	components of each pixel are next scaled by the	four
     1D	GL_CONVOLUTION_FILTER_SCALE_EXT	parameters and biased by the four 1D
     GL_CONVOLUTION_FILTER_BIAS_EXT parameters.	 (The scale and	bias
     parameters	are set	by glConvolutionParameterEXT using the
     GL_CONVOLUTION_1D_EXT target and the names



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glConvolutionFilter1DEXT(3G)   OpenGL Reference	  glConvolutionFilter1DEXT(3G)



     GL_CONVOLUTION_FILTER_SCALE_EXT and GL_CONVOLUTION_FILTER_BIAS_EXT.  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 format specified by
     internalformat.  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
     follows:

      Internal Format	   Red	 Green	 Blue	Alpha	Luminance   Intensity
      _______________________________________________________________________
      GL_LUMINANCE					    R
      GL_LUMINANCE_ALPHA			  A	    R
      GL_INTENSITY_EXT							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
     format.  They form	a one-dimensional filter kernel	image indexed with
     coordinate	i such that i starts at	0 and increases	from left to right.
     Kernel location i is derived from the ith pixel, counting from 0.

     Note that after a convolution is performed, the resulting color
     components	are also scaled	by their corresponding
     GL_POST_CONVOLUTION_c_SCALE_EXT parameters	and biased by their
     corresponding GL_POST_CONVOLUTION_c_BIAS_EXT parameters (where c takes on
     the values	RED, GREEN, BLUE, and ALPHA).  These parameters	are set	by
     glPixelTransfer.

ERRORS
     GL_INVALID_ENUM is	generated if target is not GL_CONVOLUTION_1D_EXT.

     GL_INVALID_ENUM is	generated if internalformat is not one of the
     allowable 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
     glGetConvolutionParameterEXT using	target GL_CONVOLUTION_1D_EXT and name
     GL_MAX_CONVOLUTION_WIDTH_EXT.

     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 glConvolutionFilter1DEXT is executed
     between the execution of glBegin and the corresponding execution of
     glEnd.




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glConvolutionFilter1DEXT(3G)   OpenGL Reference	  glConvolutionFilter1DEXT(3G)



     If	type is	set to GL_UNSIGNED_BYTE_3_3_2_EXT,
     GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT,
     GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT and	the
     EXT_packed_pixels extension is not	supported then a GL_INVALID_ENUM error
     is	generated.

ASSOCIATED GETS
     glGetConvolutionParameterEXT, glGetConvolutionFilterEXT


MACHINE	DEPENDENCIES
     glConvolutionFilter1DEXT is not supported on RealityEngine,
     RealityEngine2, and VTX systems.

     Loading a convolution filter with some combinations of pixel transfer
     modes may be unreliable on	InfiniteReality	systems.  Straightforward
     transfers are known to work, though.  The remaining problems will be
     fixed in the next release.


SEE ALSO
     glConvolutionFilter2DEXT, glSeparableFilter2DEXT,
     glConvolutionParameterEXT,	glEnable with parameter	GL_CONVOLUTION_1D_EXT,
     glPixelTransfer.































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