I wasn't quite sure where to put this, but anywho...

I have a C++ class that loads the data from a MD2 model into memory. I am trying to convert this into Java, but since I am not as familiar with java as I am with C++, I am having a bit of difficulty at one point. Instead of pasting the entire C++ code (it is rather lengthy), I will just supply the relevant parts:


first off, I have a few structs that look like this:


then I have a seperate class called Model that contains a private variable like this:


and then the C++ code I am stuck on is in a method called LoadModel():



I can't for the life of me get this much converted to Java. Everything else in the method I can get working, but if I convert the structures and variables to how I THINK they should be represented in java, the loop at the end becomes impossible to wrap my head around... Any help on this?

Also, should I just use native code for this instead?

Ok so I got most of it. The only problem I ma having now is the following line:

vertexListPtr = (Vector*)&vertexList[numVertices * j];

Look up at the code to see what everything is defined as.

You can convert to the following block of code assuming your vertexList is an array of Vector objects and the Frame object has public member variables scale, fp, and translate.

Hey, thanks for the info! Unfortunately, it still didn't work. Although I did change it a little:

When I tried to initialize fp[j].v[0], fp[j].v[1], and fp[j].v[2] before entering the loop you gave me it kept giving me an exception, so I tried something else. here is my code. I feel like I am so close, but so far away:

Ok, so I tried an alternate method which is closer to your idea, and it sitll didn't work, but here it is:



Any ideas? This one little section of code is driving me insane! lol

frame.fp = new FramePoint[numFrames];

You are creating an array, but are not initializing fp[0 to 3]

frame.fp[0] = new FramePoint();
frame.fp[1] = new FramePoint();
frame.fp[2] = new FramePoint();

You can likely do this in the for loop.

Note that the FramePoint constructor should also initialize whatever the v[] member variable is as well. Create the v[] array and also create new objects in that array.

I don't know your programming background, but it could help to take a step back and get up to speed on Java a little more and work on some simpler games until Java is familiar. Jumping in and porting model loading and animation code from C is not an easy initial step per se..

Of course once you get this to compile and all that it would be a good idea to try and verify the data loaded before moving onto the next stage. Without seeing how you are handling byte data when loading and also dealing with any further algorithm issues keep in mind that Java only supports signed primitives whereas in C there is unsigned data and often in the Quake level and model data unsigned bytes are used. Just a FYI / keep in mind point if you run into further issues.

Ok cool, thanks... I guess when I failed to remember I was using classes and not structures now, when converting the structs over haha... Silly me... But yea, I am very good at C/C++, but java I just started learning near the beginning of the summer. I actually have an extensive java class this comeing semester at the university, so I am hoping that will help me out a bit... I am not bad at java by any means... It's just entirely different (more so than you would think) comeing over from C/C++. I figured since I was fairly familiar with the OO sde of C/C++ (with libraries such as the wxWidgets library and OpenGL), that it wouldn't be much differnt... I am getting there though... practice makes perfect, right?

Ok, so I tried your recomendation like so:



but it still fails. :/

Also, here is my FramePoint class:



Notice that v[] is an array of bytes.... How can I initialize a primitive like byte? If I use null it throws an error on compile. Also, I thought that you didn't need to initialize a variable of the byte data type. I was under the impression that it was the only one you didn't need to.

Indeed.. It sounds like you have the enthusiasm and passion to get right in there and take the bull by the horns though and that is the most important aspect of diving into a new technology or platform!

The thing that was throwing you off with the "vertexListPtr = (Vector*)&vertexList[numVertices * j]" statement and indexing in the C for loop was that the counter (i) used in the C code was doing pointer arithmetic / indexing so it's possible to use one counter to iterate through the local variables and sub section of the vertex list. With Java you need two counters to keep track of the position in the vertex list and the local iteration (numVectices).

Definitely post some results back here when you get some cool stuff working!

Lol I plan on it! Do you mind taking another glance at my previous post? I threw in a few questions on the ninja.

Also, I think I found the problem (or at least one of them), but I have no idea how to go about fixing it... lol I initialized the frame.fp[] array as having numFrams values. Then, further down in the code, when I am within the inner loop of the notorious double loops that have been giving me so much problems, I am looping through the fram.fp[] array numVertices times. The problem is that numVertices is MUCH higher than numFrames, so it is actually reaching the end of the frame.fp[] array before it exits the inner loop... any idea how to go about fixing this? In the c++ Frame struct, I had frame.fp[] initialized differntly (that will not work in java) and I also had frame declared as a pointer (Frame frame;). Without direct access to memory life is a bitch. XD

>Without direct access to memory life is a bitch.

Nah... It can make life a lot easier and way less error prone, but yeah tricks abound when you can directly access memory.

Of course with just seeing snippets of code and not seeing the entire original and modifications you've had to make on the way it's hard to say, but verify that for frame.fp[] what counter you are supposed to use. Likely it should be the outer loop counter indexing on numFrames and not the numVertices. The inner loop numVertices is to iterate and set values of the vertexList.

Wooo! I finally figured it out! I was confused in my last post because I had already tried switching the index of frame.fp[] in the inner loop to frame.fp[i], but it still wouldn't work... After some more hunting, I finally found the problem... I had:

vertexList = new Vector[header.numXYZ * header.numFrames];

but I never initialized each value.

I added the following code right after it and it fixed everything:

for(int i = 0; i < (header.numXYZ * header.numFrames); i++)
{
vertexList[i] = new Vector();
}