Completely new node class

During my last days I've been working on implementing new class for my nodes. I took the conception to make each node not 1 by 1 quad, by n by n quads. This means that each my node will consist of n by n nodes (16x16 for example). After the node is being created, it's transformed into a single mesh and then attacked to the scene. The reason for this was bad frame-per-second rate with previous ways, because each frame each my quad was send to GPU for rendering. And because of huge amount of quads, each sending slowed down the performance. GPU can handle complex meshes very fast if sent to GPU as a single mesh.

So, by rewriting the Node class to this new approach, the fps increased more than 100 times! Now that's what I call HUGE :)

Also, the node's constructor allows now to set the desired amount of quads on each side. The example below shows the cube with 128x128 quads on each cube's face.

And with this one it's still over 150 frames per second.

Performance issues and ideas

It seems that performance issues are caused by too many nodes attached to the rootNode manager (the one that handles all the geometry in the scene). I have asked the question on the forum (here) and there were some solutions gives, as well as some ideas made up in my mind.

Well, one way is to somehow lower the amount of custom nodes while saving the same amount of triangles in the scene. This can be done if I make a constant mesh from many nodes and only then add it to the rootNode manager. So I have to write a procedure that reads all my quad tree, finds all nodes that have to be rendered (i.e. are leafs) that are on the same level in my quad tree, and makes a constant mesh (TriMesh to be exact by java terminology) and then pass it to the scene manager. And that for all tree levels.

Another thought that I had was related with splitting. In my previous posts I mentioned that according to my splitting procedure the quad splits on 4 smaller. In future the idea was to split the quad if camera is close o it so to add more detail. But splitting only one segment each time won't add much of a nice picture, imho. I think I need to "split" quads for some segment bigger than one parent quad. That way adding more detail won't be so.. mmm... so rude, maybe. Somehow like this.

So, I believe I will focus on this.

Cube to Sphere mapping

Whooah...

Finaly I have managed to solve all bugs in my way to map coordinates for each vertex from primary cube so to form a sphere. Planet should look like a sphere, because nobody likes cubic planets :)

The main equations for transforming coordinates of cube to spherical are the following:

For that reasons I have made a "final" class called c_MyMath for keeping all the future equation functions there.

After a bit of testing I found that it was a bad idea to store spherical coordinates of each vertex multiplied by planetary scale factor (the radius of the planet) because while doing scaling in the node's constructor, I needed to take care of scaling during quad splitting also. I thought it's whatever if I do the scaling for each vertex in the constructor and in splitting procedure, and doing it just before the prerender function, which finds all the quads that should be rendered and then apply the scaling. I understand that it's better to handle everything from the start (not just before th rendering) but for now I have decided to leave things as they were.

Now the protoplanet looks finally like a sphere!

Dealing with quadtrees 3: The cube

I have managed to draw a single quad on the window, and make split algorithm work properly. It uses parent quad's vertex coordinates and makes new 4 quads and calculates it's vertex coordinates.

I have realized, that basically I need to store in some king of list all my new quads, and later on I also need to make a procedure (at the moment just a simple one) that looks through this lists and makes another one, containing only leafs - quads that have to be rendered.

To store it I used LinkedList class. Very useful.

I needed to make a cube that consist of 6 quads (6 sides) at the moment of creation. The problem was that by defining a tree (as it should be defined) it should have only one root (quad, or whatever). By making 6 sides, I basically create 6 roots, and I was afraid that I will have problems later when I will have to make some kind of procedure, that will need to find all quads that have to be rendered, because that way I will need to call it for each 6 primary quads. The solution with lists I found quite resultive.

This is the result of primary cube. At the moment I have decided to draw cube so that it's center is in the (0;0;0) and vertexes have by default +1 or -1 in all direction, multiplied by scale factor. Later on I will have to add algorithm that could place the cube in any coordinates so that all formulas stay consistant and correct. But that will be later.

This is the result of splitting the primary cube 3 times (6 sides times 4^3 gives 384 quads).

By now it works, by the framerate results doesn't make me happy, because by dividing the prime cube 5 times gives only 20 fps and that's odd.

Next step will be finding out why the hell fps are so small :) and second make a sphere out of cube - it should be spherical planet, not cube like :)