1991-2006 Silicon Graphics, Inc.
glGetColorTable 3G
glGetColorTable retrieve contents of a color lookup table

## C Specification

void `glGetColorTable` GLenum target GLenum format GLenum type GLvoid * table

## Parameters

target

  Must be `GL_COLOR_TABLE`, `GL_POST_CONVOLUTION_COLOR_TABLE`, or `GL_POST_COLOR_MATRIX_COLOR_TABLE`.

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_BGR`, `GL_RGBA`, and `GL_BGRA`.

type

  The type of the pixel data in table. Symbolic constants `GL_UNSIGNED_BYTE`, `GL_BYTE`, `GL_BITMAP`, `GL_UNSIGNED_SHORT`, `GL_SHORT`, `GL_UNSIGNED_INT`, `GL_INT`, `GL_FLOAT`, `GL_UNSIGNED_BYTE_3_3_2`, `GL_UNSIGNED_BYTE_2_3_3_REV`, `GL_UNSIGNED_SHORT_5_6_5`, `GL_UNSIGNED_SHORT_5_6_5_REV`, `GL_UNSIGNED_SHORT_4_4_4_4`, `GL_UNSIGNED_SHORT_4_4_4_4_REV`, `GL_UNSIGNED_SHORT_5_5_5_1`, `GL_UNSIGNED_SHORT_1_5_5_5_REV`, `GL_UNSIGNED_INT_8_8_8_8`, `GL_UNSIGNED_INT_8_8_8_8_REV`, `GL_UNSIGNED_INT_10_10_10_2`, and `GL_UNSIGNED_INT_2_10_10_10_REV` are accepted.

table

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

## Description

`glGetColorTable` 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.

If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER` target (see glBindBuffer) while a histogram table is requested, table is treated as a byte offset into the buffer object's data store.

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

## Notes

`glGetColorTable` is present only if `ARB_imaging` is returned when glGetString is called with an argument of `GL_EXTENSIONS`.

## Errors

`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 type is one of `GL_UNSIGNED_BYTE_3_3_2`, `GL_UNSIGNED_BYTE_2_3_3_REV`, `GL_UNSIGNED_SHORT_5_6_5`, or `GL_UNSIGNED_SHORT_5_6_5_REV` and format is not `GL_RGB`.

`GL_INVALID_OPERATION` is generated if type is one of `GL_UNSIGNED_SHORT_4_4_4_4`, `GL_UNSIGNED_SHORT_4_4_4_4_REV`, `GL_UNSIGNED_SHORT_5_5_5_1`, `GL_UNSIGNED_SHORT_1_5_5_5_REV`, `GL_UNSIGNED_INT_8_8_8_8`, `GL_UNSIGNED_INT_8_8_8_8_REV`, `GL_UNSIGNED_INT_10_10_10_2`, or `GL_UNSIGNED_INT_2_10_10_10_REV` and format is neither `GL_RGBA` nor `GL_BGRA`.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER` target and the buffer object's data store is currently mapped.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER` target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER` target and table is not evenly divisible into the number of bytes needed to store in memory a datum indicated by type.

`GL_INVALID_OPERATION` is generated if `glGetColorTable` is executed between the execution of glBegin and the corresponding execution of glEnd.

## Associated Gets

glGetColorTableParameter

glGet with argument `GL_PIXEL_PACK_BUFFER_BINDING`

## See Also

glColorTable, glColorTableParameter

## Copyright

Copyright 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/.