   D3DLOCKED_RECT (applying changes)
  So I've locked an entire LPDIRECT3DTEXTURE9 and then done some modifications to the pixel data pointed to by D3DLOCKED_RECT::pBits, and everything seems to work fine.  But here's my question: how do I apply those changes to the original texture?   
  You call UnlockRect().To all intents and purposes, the data in D3DLOCKED_RECT::pBits is the original texture data, and calling UnlockRect() tells D3D that you've finished modifying it.   ;  Alright, thanks!  I had tried that before, but I realized that the radius of the circle I was modifying was too small for any of my changes to be noticeable.  I appreciate the help.   