   Bouncy effect on a texture?
  I'm trying to recreate a warp effect( when there is an explosion ) that you see in games like geometry wars/geoDefese in an iPhone game. From studying the effects in geoDefense all thats going on is the area around the explosion goes in and out on the z axis like if you were looking at a stretchy material that had a ball bouncing on it. Another example is a trampoline with someone bouncing on it. How would someone manipulate a 2d texture in a 3d plane to replicate this type of bouncy effect?From thinking about, it seems that you would define a point and a radius and you would manipulate the z coordinate of all vertices that are within this radius. Maybe when the texture is bouncing downward, you have your point defined at a specific distance away from the camera on the z axis and have all points within your radius move towards that point in some fashion that tapers off the further away from the point you are and just do the opposite with the bouncing up effect.Any help would be appreciated with this.Thanks   