Using VermelGen

Before you start using VermelGen there are a number of things that you need to make sure of. Firstly - have you got the JVerge class libraries installed? Next check that you have included the ui components package installed as well. This is included as part of the VermelGen distribution and should be installed under the vlc heirarchy that you used for the JVerge class files.

Installation in more Detail

Once you have done this, there are a number of other things to start considering. VermelGen will run correctly if the application classes are not part of your classpath. You might consider adding them to it as well. Why would you do this I here you ask? Well, Netscape does some extra things which just make everything appear nicer. Any dialog boxes will come up without the status bar in them with the old "Unsigned Java Applet" warning. In a number of our windows we have our own status bar showing. The following shots indicate the difference in appearance.

Also to consider is where to put the VermelGen application. As there is no install program then you can place it anywhere. We recommend placing it as a separate directory from the usual user account home directory. We want as many people to play with it as possible! It also means that you only need to set the CLASSPATH up once.

The final part to complete the installation is a quick edit of the toplevel HTML file. This is called index.html in the install directory. In there you will find a param tag that is passing a value called top_directory. The value here needs to be changed to the directory that you have installed VermelGen into. If you do not change it then none of the images will appear.

Running the Application

Now that you have everything installed correctly, running VermelGen is as simple as opening up the HTML file called index.html in the VermelGen directory.

The main Browser window

Opening the file will load an empty VRML scene (and hence the browser) with 4 buttons directly underneath it. These buttons give you access to the main functional parts of VermelGen.

Starting from the left - you can show the editor window, print out the current VRML scene, show what the last output was or show the help window. With the current release - the help window does not work at all. Ideally I would like to have this button pop up the web browser with HTML documentation , but I can't get that to work for some reason. If anyone is able to get it worked out, or send me example working code I would be most greatful.

The Editor Window

The editor window is where all the action happens. Here is where you perform the general scene editing. At the top there is the usual menubar. If a menu item is not functional, it is not greyed out as normally expected, instead it just pops up a warning dialog box tell you of such.

The first menu is the usual File menu, here you can create a new scene, print out the current contents or close the window. Although the option says Save it really just opens the output window and displays the contents of the current scene. If the scene does not match what you expect then either the result is that the browser itself does not support one of the nodes that you have added, or that JVerge has a bug in it. In either case, please let me know so that I can fix it. I did have a number of bugs fixed, but when I had the crash I lost a number of those fixes and I have yet to determine if all the old bugs have been once again removed.

To add a new node to the scene, simply select a node in the tree and then click on one of the buttons on the right or use the node menu. VermelGen enforces very strick VRML syntax. If a node is not permitted as a child of another then the editor will not let you add it at all. In some cases it is much more strict than the spec allows. In a number of circumstances this is simply because it is almost impossible to do some of the things a file format can do that the Java code cannot. Collision nodes are a good example.

Cut and paste have been implemented in this version, however it is very dodgy. Unfortunately there is no copy command - this requires me having to implement cloning in the JVerge classes - something that is not available at the moment. Cut and paste does work, however the screen results probably will not reflect this. The problem is that the tree display code does not do a recursive display of all children when a node is added. We have not bothered to fix this as we are in the process of completely rewritting the code in Java 1.1 for the next release. For the moment you will just have to live with the bug - sorry.

Once you have some scene that you are reasonably happy with, you can display the VRML source in a separate window by using File | Save or the Write Output button. This will open a window that will display the code. Due to the restrictions of applets writing to the hard drive, the only way that you can now transfer the resulting scene into a real file is to copy the contents of this window into a text editor and then save that file. We hope that with the coming of Java 1.1 in browsers that we will have less of these restrictions and will be able to write directly to the harddrive.

The Pixel Texture Editor

The Pixel Texture editor is much expanded over the original version. Now what you have is almost good enough to rival PaintBrush. Most of the standard operations are there (complete with the oh-so-sexy Win95 style flush buttons!). One thing that we have noticed is that at 1:1 scale things can get very slow. We can't work out why because as a standalone it absolutely screams. The weirdest part is that when you zoom in or out everything runs really nicely. So the obvious suggestion is never to operate at 1:1, but say 2:1 or so for proper speed.

Note that we do have some very difficult problems to deal with. Under the EAI there is no definition of what the byte order for the SFImage setValue/getValue methods are. Therefore, adding what you think is a texture the right way around may indeed produce some really wierd results (CosmoPlayer cannot handle this at all, throws a lot of error messages).

Extrusion Editor

Another one that seems to suffer some wierd speed problems. Some machines run really quickly and others like a dog. There are two parts to the editor. The first windows displayed are the spine editor. By clicking and dragging on a line you can alter the spine. The top left corner is the rotation and scale of the cross-section at that point. It will not move if you have selected the original end of the extrusion (as per the VRML spec - the spine at index 0 cannot be effected by a rotate or scale).

Clicking on the top left button will bring up the cross-section editor where a similar click and drag policy allows you to edit the general cross-section. When you return to the spine windows this new section will be reflected with the same rotation and scale as the previously set spine modifications. There are some bugs with the rotation which are outlined on the bugs page.

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