" The code below is to show how a heirarchy of objects can be made within a scenegraph.
In other words, how there can be a parent/child relationship between objects such
that when a parent is rotated or translated, the children move is respect to it's
parent movement. A robotic arm is used in this example because this is what I'm
using OSG for."
The graph is displayed "under" (behind) the normal bar chart you get when you press 's' twice. It doesn't hide the normal stats, you can still read them without any trouble, and that way, it doesn't take any more screen space. It starts from the left, and will scroll left when there is enough data to fill the screen width. The graph lines have the same colors we're used to (except I made the event color a bit bluer, so it's not exactly the same as the update color). A screen shot is attached.
The lines get a bit confused when they're all overlapping at the bottom of the graph, but I think that's the least of our concerns (if they're all at the bottom of the graph - except FPS of course - then great!).
The only thing I'm not very keen about is that to make things simple, I clamp the values to a given maximum. Right now, the maximums I have set are:
* Frame rate: 100 fps (people have 60, 75, 85Hz refresh rates, so there's no one right value, but I think 100 is OK)
* Stats: 0.016 seconds (what you need to get 60Hz minimum)
This could be changed so that the scale of the graph changes according to the maximum value in the last screenful of the graph instead of clamping values. We would then need to display the scale for each value on the side of the graph, because if the scale changes, you need to know what it is at this moment.
I tried to make things easy to change, so for example if you don't like that the graph is in the same space as the normal stats bars, it's easy to move it anywhere else, and make it have other dimensions. The maximums and colors are also easy to change.
The impact on performance should be minimal, since it's one vertex per graph line that's added per frame, and vertices are removed when they scroll off the screen, so you'll never have more than say 1280 * (3 + ncameras) vertices on the screen at one time. No polygons, I used line strips. The scrolling is done with a MatrixTransform."
