The ilSetData function updates the current image data with new data.

Data

Specifies the new image data to update the image with.

ilSetData just updates the current bound image data (bound by ilBindImage) with new data of the same size. This way new memory does not have to be allocated, so transfers are much faster.

IL_ILLEGAL_OPERATION - There is currently no image bound. Use ilGenImages and ilBindImage before calling this function.
IL_INVALID_PARAM - Data was NULL.