   Making an object appear to sink into the ground
  Hi all,I know this is a very 'abstract' question, and for that I apologize. I'm trying to achieve what should be a straight forward effect. I want to have a simple 2d drawing appear to be sinking into the ground when a user hits my object. I'm curious, can anyone point me in the right direction to head with OpenGL on how to achieve something such as taking a sprite, and incrementally making it look like it's sinking vertically into the floor?Thanks for your assistance.   
  If you're using 3-d geometry in any way, you could just use the depth buffer for this. If it's strictly 2-d, you could use the painter's algorithm (that is, draw whatever the object is sinking into over the object itself). If there's a 3-d visual component, but the game is essentially 2-d (like in some side-scrolling games), you could make the object appear to sink by altering the rendering geometry over time (e.g. keep the bottom of the quad at the same location, lower the top of the quad progressively, and adjust the texture coordinates accordingly as you go).   ;  You understand how animation works in general, right?Try drawing successive frames of the effect, and then thinking about how you drew them. :)   ;  If you are in 3D, this should be pretty easy.  Just move your sprite lower and lower into the ground and the depth buffer will make sure that the ground covers your sprite.  If you are in 2D then it could be a little tricky.  It depends on how you are rendering your "ground" and how you are rendering your sprites   