Fix Graphics Issues with Waterfall Display

The current waterfall display lags significantly behind realtime. How we do this needs to be rethought. There are two different ways to do this:

• OpenGL
• CoreAnimation

The OpenGL method might be the better one for the longer term, but might be less flexible and harder to implement. It involves creating a texture that is a bitmap image of the waterfall. You can set this texture so that it "wraps". You then replace the texture one line at a time, and increment a pointer into the starting line of the texture. You can then move the texture down the screen incrementally to product the effect. One thing you could do with this system is not only have color represent the signal strength dimension, but also the Z dimension in 3D.

The CoreAnimation method might prove easier to do, although I'm not sure of the performance yet. CoreAnimation deals with layers that are composited on screen. I don't know what the practical limitation of the number of these layers is. What we could do is create one layer for each line of the display. When a new line is encountered, we can shift each of the other layers down by one, which requires a simple Y plane transform that is included in CoreAnimation. We then pop the layer off of the bottom, and push a new layer on the top. One of the advantages of this method is that you can use all the nice Quartz prepackaged animations as well, which could be cool.