glGetColorTableSGI(3G)	       OpenGL Reference		glGetColorTableSGI(3G)

NAME    [Toc]    [Back]

     glGetColorTableSGI	- retrieve contents of a color lookup table

C SPECIFICATION    [Toc]    [Back]

     void glGetColorTableSGI( GLenum target,
			      GLenum format,
			      GLenum type,
			      GLvoid *table )

PARAMETERS    [Toc]    [Back]

     target  Must be GL_TEXTURE_COLOR_TABLE_SGI, GL_COLOR_TABLE_SGI,
	     GL_POST_CONVOLUTION_COLOR_TABLE_SGI, or
	     GL_POST_COLOR_MATRIX_COLOR_TABLE_SGI.

     format  The format	of the pixel data in table.  The possible values are
	     GL_RED, GL_GREEN, GL_BLUE,	GL_ALPHA, GL_LUMINANCE,
	     GL_LUMINANCE_ALPHA, GL_RGB, GL_RGBA, and GL_ABGR_EXT.

     type    The type of the pixel data	in table.  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.

     table   Pointer to	a one-dimensional array	of pixel data containing the
	     contents of the color table.

DESCRIPTION    [Toc]    [Back]

     glGetColorTableSGI	is part	of the SGI_color_table extension, and is also
     used by the SGI_texture_color_table extension.

     glGetColorTableSGI	returns	in table the contents of the color table
     specified by target. No pixel transfer operations are performed, but
     pixel storage modes that are applicable to	glReadPixels are performed.

     Color components that are requested in the	specified format, but which
     are not included in the internal format of	the color lookup table,	are
     returned as zero.	The assignments	of internal color components to	the
     components	requested by format are

		     Internal Component	  Resulting Component
		     ________________________________________
			    red			  red
			   green		 green
			    blue		 blue
			   alpha		 alpha
			 luminance		  red
			 intensity		  red





									Page 1






glGetColorTableSGI(3G)	       OpenGL Reference		glGetColorTableSGI(3G)

NOTES    [Toc]    [Back]

     If	target is set to GL_TEXTURE_COLOR_TABLE_SGI and	the
     SGI_texture_color_table extension is not supported	then a GL_INVALID_ENUM
     error is generated.

     If	target is set to GL_COLOR_TABLE_SGI,
     GL_POST_CONVOLUTION_COLOR_TABLE_SGI, or
     GL_POST_COLOR_MATRIX_COLOR_TABLE_SGI and the SGI_color_table extension is
     not supported then	an GL_INVALID_ENUM error is generated.

     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 an GL_INVALID_ENUM
     error is generated.

     See glIntro for more information on using extensions.

ERRORS    [Toc]    [Back]

     GL_INVALID_ENUM is	generated if target is not one of the allowable
     values.

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


MACHINE	DEPENDENCIES
     RealityEngine, RealityEngine2, and	VTX systems do not support
     glGetColorTableSGI; calling it results in a GL_INVALID_OPERATION error.

SEE ALSO    [Toc]    [Back]

     glColorTableSGI.  glColorTableParameterSGI.  glGetColorTableParameterSGI.


									PPPPaaaaggggeeee 2222