glGetPixelMapusv

glGetPixelMap: man2/glGetPixelMap.xml

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.

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