   texture clipmaps
  id like some more info on how texture clipmaps work... ive been looking at some papers but either they are very vague or overly complicated...as far as ive understood the basic idea is to have several smaller textures which u update from a larger texture... where each texture level represents a larger and less detailed part of the larger texture...however there are a few things i dont understand... how do u update the textures? do u "Lock" them and then update the "L or +" parts that needs to be updated... this would be rather slow? Another option i know of is using RTT.. but this has several other issue... how do u send data from the larger texture to the pixelshader? also if u use RTT how do u update "parts" of the texture... doesnt RTT render to the entire screen/texture?.. even if u set up the RTT to fit the part that needs to be updated, how do u render to a part of a texture? do u store the larger texture in systemmemory?... if so how do u update the texture in system memory with the data on the HD... any help appreciated (including links to info)   