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GLCOPYCOLORTABLE(3G)			  OpenGL Manual 		     GLCOPYCOLORTABLE(3G)

NAME
       glCopyColorTable - copy pixels into a color table

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

PARAMETERS
       target
	   The color table target. Must be GL_COLOR_TABLE, GL_POST_CONVOLUTION_COLOR_TABLE, or
	   GL_POST_COLOR_MATRIX_COLOR_TABLE.

       internalformat
	   The internal storage format of the texture image. Must be one of the following
	   symbolic constants: 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
	   The x coordinate of the lower-left corner of the pixel rectangle to be transferred to
	   the color table.

       y
	   The y coordinate of the lower-left corner of the pixel rectangle to be transferred to
	   the color table.

       width
	   The width of the pixel rectangle.

DESCRIPTION
       glCopyColorTable loads a color table with pixels from the current GL_READ_BUFFER (rather
       than from main memory, as is the case for glColorTable()).

       The screen-aligned pixel rectangle with lower-left corner at (x,\ y) having width width
       and height 1 is loaded into the color table. If any pixels within this region are outside
       the window that is associated with the GL context, the values obtained for those pixels
       are undefined.

       The pixels in the rectangle are processed just as if glReadPixels() were called, with
       internalformat set to RGBA, but processing stops after the final conversion to RGBA.

       The four scale parameters and the four bias parameters that are defined for the table are
       then used to scale and bias the R, G, B, and A components of each pixel. The scale and
       bias parameters are set by calling glColorTableParameter().

       Next, the R, G, B, and A values are clamped to the range 0 1. 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 |			   Red |			 Green |			 Blue | 			Alpha | 			Luminance |			    Intensity |
       |Format				 |			       |			       |			      | 			      | 				  |				      |
       |				 |			       |			       |			      | 			      | 				  |				      |
       +---------------------------------+-----------------------------+-------------------------------+------------------------------+-------------------------------+-----------------------------------+-----------------------------------+
       |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 	      | 				  |				      |
       +---------------------------------+-----------------------------+-------------------------------+------------------------------+-------------------------------+-----------------------------------+-----------------------------------+

       Finally, the red, green, blue, alpha, luminance, and/or intensity components of the
       resulting pixels are stored in the color table. They form a one-dimensional table with
       indices in the range 0 width - 1.

NOTES
       glCopyColorTable is available only if ARB_imaging is returned from calling glGetString()
       with an argument of GL_EXTENSIONS.

ERRORS
       GL_INVALID_ENUM is generated when target is not one of the allowable values.

       GL_INVALID_VALUE is generated if width is less than zero.

       GL_INVALID_VALUE is generated if internalformat is not one of the allowable values.

       GL_TABLE_TOO_LARGE is generated if the requested color table is too large to be supported
       by the implementation.

       GL_INVALID_OPERATION is generated if glCopyColorTable is executed between the execution of
       glBegin() and the corresponding execution of glEnd().

ASSOCIATED GETS
       glGetColorTable(), glGetColorTableParameter()

SEE ALSO
       glColorTable(), glColorTableParameter(), glReadPixels()

COPYRIGHT
       Copyright (C) 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/.

AUTHORS
       opengl.org

opengl.org				    06/10/2014			     GLCOPYCOLORTABLE(3G)
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