glgetcolortablesgi(3G)



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



NAME
     glGetColorTableSGI - retrieve contents of a color lookup table


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


PARAMETERS
     target  Must be GLTEXTURECOLORTABLESGI, GLCOLORTABLESGI,
             GLPOSTCONVOLUTIONCOLORTABLESGI, or
             GLPOSTCOLORMATRIXCOLORTABLESGI.

     format  The format of the pixel data in table.  The possible values are
             GLRED, GLGREEN, GLBLUE, GLALPHA, GLLUMINANCE,
             GLLUMINANCEALPHA, GLRGB, GLRGBA, and GLABGREXT.

     type    The type of the pixel data in table.  The allowable values are
             GLUNSIGNEDBYTE, GLBYTE, GLUNSIGNEDSHORT, GLSHORT,
             GLUNSIGNEDINT, GLINT, GLFLOAT, GLUNSIGNEDBYTE332EXT,
             GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
             GLUNSIGNEDINT8888EXT, and GLUNSIGNEDINT1010102EXT.

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

DESCRIPTION
     glGetColorTableSGI is part of the SGIcolortable extension, and is also
     used by the SGItexturecolortable 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





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



NOTES
     If target is set to GLTEXTURECOLORTABLESGI and the
     SGItexturecolortable extension is not supported then a GLINVALIDENUM
     error is generated.

     If target is set to GLCOLORTABLESGI,
     GLPOSTCONVOLUTIONCOLORTABLESGI, or
     GLPOSTCOLORMATRIXCOLORTABLESGI and the SGIcolortable extension is
     not supported then an GLINVALIDENUM error is generated.

     If type is set to GLUNSIGNEDBYTE332EXT,
     GLUNSIGNEDSHORT4444EXT, GLUNSIGNEDSHORT5551EXT,
     GLUNSIGNEDINT8888EXT, or GLUNSIGNEDINT1010102EXT and the
     EXTpackedpixels extension is not supported then an GLINVALIDENUM
     error is generated.

     See glIntro for more information on using extensions.

ERRORS
     GLINVALIDENUM is generated if target is not one of the allowable
     values.

     GLINVALIDENUM is generated if format is not one of the allowable
     values.

     GLINVALIDENUM is generated if type is not one of the allowable values.

     GLINVALIDOPERATION 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 GLINVALIDOPERATION error.


SEE ALSO
     glColorTableSGI.  glColorTableParameterSGI.  glGetColorTableParameterSGI.
















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