Quad isn't the best?

While reading some articles over the internet I am deeply starting to thing, that the quad-based LoD algorithm wasn't the best idea. I think so mainly because using such technique on a rather flat surfaces I still will have a lot of unneeded detail.

To demonstrate what I mean, I have found some pictures on the internet.

The picture to the left illustrates something like a hill near the flat ground. The hill itself is more "extruded" from the surface, and it needs more vertexes to represent all it's slopes and caves. It's more logical to add extra detail to the hills, and do not extra detail where the area is completely flat. This is the algorithm I need to implement if I want more complex terrain look more natural. This algorithm is called Optimally Adapted Meshes (OAM).

Unlike previous picture, this one exactly represents the technique I use at the moment. It can be seen with naked eyes that there are way more vertexes used on the areas, where you actually do not need them.

The OAM algorithm, or it's implementation to visualize terrains in realtime (Real-time Optimally Adapted Meshes, or ROAM) uses a height map to determine for each vertex it's error value - the heights around it so see if the area around it is flat or it needs more detail. Based on error value it determines where the extra detail should be added and where it's ok to leave the same amount of vertexes at the moment.

I also need to think in parallel the scaling problem, and implement it inside.

Links

Roam info & papers: 1, 2, 3, 4

 

Glitches

I have realized, that something needs to be changed in my code. I did some tests trying to see how program responses to big numbers. I have created a planet with the size exact to Earth's, and tried to fly here and there to see the performance, and then I ran to some unpleasant glitches.

This is taken from the stationary orbit at 1100 km from the surface of the virtual Earth. Strange thing that this artifacts not always appears (maybe I should call them UFO? :) ). It seems that this happens when some other processes run in background and use CPU resources a lot. I haven't tested it on other computers, maybe it's hardware specific.

I also noticed, that memory allocation and garbage collection isn't quite good, because the project constantly drains memory while runs. The problem is in LoD code, definitely.