1991-2006
Silicon Graphics, Inc.
glGetPixelMap
3G

# glGetPixelMap

return the specified pixel map

## C Specification

                    void glGetPixelMapfv
                    GLenum map
                    GLfloat * data

                    void glGetPixelMapuiv
                    GLenum map
                    GLuint * data

                    void glGetPixelMapusv
                    GLenum map
                    GLushort * data

## Parameters

`map`

  Specifies the name of the pixel map to return. Accepted values are `GL_PIXEL_MAP_I_TO_I`, `GL_PIXEL_MAP_S_TO_S`, `GL_PIXEL_MAP_I_TO_R`, `GL_PIXEL_MAP_I_TO_G`, `GL_PIXEL_MAP_I_TO_B`, `GL_PIXEL_MAP_I_TO_A`, `GL_PIXEL_MAP_R_TO_R`, `GL_PIXEL_MAP_G_TO_G`, `GL_PIXEL_MAP_B_TO_B`, and `GL_PIXEL_MAP_A_TO_A`.

`data`

  Returns the pixel map contents.

## Description

See the glPixelMap reference page for a description of the acceptable values for the `map` parameter. `glGetPixelMap` returns in `data` the contents of the pixel map specified in `map`. Pixel maps are used during the execution of glReadPixels, glDrawPixels, glCopyPixels, glTexImage1D, glTexImage2D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, and glCopyTexSubImage3D. to map color indices, stencil indices, color components, and depth components to other values.

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

Unsigned integer values, if requested, are linearly mapped from the internal fixed or floating-point representation such that 1.0 maps to the largest representable integer value, and 0.0 maps to 0. Return unsigned integer values are undefined if the map value was not in the range [0,1].

To determine the required size of `map`, call glGet with the appropriate symbolic constant.

## Notes

If an error is generated, no change is made to the contents of `data`.

## Errors

`GL_INVALID_ENUM` is generated if `map` is not an accepted value.

`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 by `glGetPixelMapfv` if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER` target and `data` is not evenly divisible into the number of bytes needed to store in memory a GLfloat datum.

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

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

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

## Associated Gets

glGet with argument `GL_PIXEL_MAP_I_TO_I_SIZE`

glGet with argument `GL_PIXEL_MAP_S_TO_S_SIZE`

glGet with argument `GL_PIXEL_MAP_I_TO_R_SIZE`

glGet with argument `GL_PIXEL_MAP_I_TO_G_SIZE`

glGet with argument `GL_PIXEL_MAP_I_TO_B_SIZE`

glGet with argument `GL_PIXEL_MAP_I_TO_A_SIZE`

glGet with argument `GL_PIXEL_MAP_R_TO_R_SIZE`

glGet with argument `GL_PIXEL_MAP_G_TO_G_SIZE`

glGet with argument `GL_PIXEL_MAP_B_TO_B_SIZE`

glGet with argument `GL_PIXEL_MAP_A_TO_A_SIZE`

glGet with argument `GL_MAX_PIXEL_MAP_TABLE`

glGet with argument `GL_PIXEL_PACK_BUFFER_BINDING`

## See Also

glColorSubTable, glColorTable, glConvolutionFilter1D, glConvolutionFilter2D, glCopyColorSubTable, glCopyColorTable, glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawPixels, glGetHistogram, glGetMinmax, glGetTexImage, glPixelMap, glPixelTransfer, glReadPixels, glSeparableFilter2D, glTexImage1D, glTexImage1D, glTexImage2D glTexImage2D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D

## 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/.