# White_dune developer documentation

## "white_dune", what's that ?

"white_dune" is a continuation of the "dune" project by Stephan F. White.
"dune" is a graphical VRML97 Editor, simple NURBS modeller and animation tool with some OpenGL scene rendering capabilities.

## white_dune program overview

In princple, the structure of the white_dune program can be written as:

1. evaluate commandline parameters
2. enter GUI (Grapical User Interface) mainloop

For details, see the file main.cpp

## white_dune GUI overview

The GUI of white_dune consists of 2 parts:

1. 2D GUI
   This handles two dimensional operations like opening windows, display icons, menus, buttons etc.
   2D GUI operations are seperated in a extra programming level, called swt (Stephan White Toolkit).
   Currently, there are two different implementations of swt written in C, one for Motif/Lesstif (Unix/Linux) and one for Win32 (M$Windows).
   For details, see the directory swt. swt use M$Windows rc files. For details about the implementation on M$Windows machines see the directory swt/rc.
2. 3D GUI
   This handles three dimensional operations. This is displaying 3D data (rendering, implemented in OpenGL) and manipulating 3D Objects.
   Some 3D operations, like mouseinput and reaction to desktop events (e.g. resize of Windows) are handled in connection with the 2D GUI (see the file Scene3DView.cpp for details).
   Additional, there are other sources of information for manipulating 3D Objects (also handled in Scene3DView.cpp): input from devices like joystick, dialbox or spaceball. Code for input from this devices is located in the file InputDevice.cpp.

The 2D GUI mainloop of white_dune is event driven. Typical events are mouse-movement, mouse-click, resize of window and so on.
Additionally the mainloop can produce timer events.
When a event occures, the matching callback function is started. The callbacks work for every subwindow of white_dune.
The following image shows the subwindows (red text) of the mainwindow.

Some 2D GUI events are distributed to the different subwindows. The distribution of this events is based on inheritance.
The class SceneView define inheritable 2D GUI callbacks like OnMouseMove and is parent class to the classes ChannelView, FieldView, Scene3DView, SceneGraphView, SceneTreeView, StatusBar, ToolbarWindow and PanedWindow. PanedWindow is parent class to the class MainWindow.

A additional callback OnUpdate is used to distribute messages like UPDATE_FIELD or UPDATE_ADD_NODE to the child classes of SceneView. OnUpdate is started by the function UpdateViews of class Scene.

Some operations require additional input of data. Then a "Dialog" is opened, that block the data input to all other windows.

*Dialog classes are all inheritable from the class Dialog, which implements functions like SaveData() and Validate().
The layout of Dialogs (as well as the layout of the menues) is defined in the dune*.rc files.

## VRML implementation overview

The class Scene (Scene.h/cpp) can be identified with one VRML file. For example Scene.write() writes the VRML file to disk.

The global variable TheApp of class DuneApp (DuneApp.h/cpp) can be identified with things that are global to all VRML files.

The internals of each VRML Nodes are implemented in the files named NodeNodeName (for example NodeTransform (NodeTransform.h/cpp), NodeShape (NodeShape.h/cpp) or NodeBox (NodeBox.h/cpp)).

Every NodeNodeName.h file contain 2 classes: the class NodeNodeName which contain functionality like draw() for 3D rendering of shapes and the class ProtoNodeName which are used to build the definitions of the VRML97 standard.
For example, the definiton of the Transform Node in the ISO/IEC 14772 standard
is implemented in the constructor of the class ProtoTransform (in file NodeTransform.cpp):

    ProtoTransform::ProtoTransform(Scene *scene)
      : Proto(scene, "Transform")
    {
        addEventIn(MFNODE, "addChildren");
        addEventIn(MFNODE, "removeChildren");
        center.set(addExposedField(SFVEC3F, "center", new SFVec3f(0.0f, 0.0f, 0.0f)));
        children.set (addExposedField(MFNODE, "children", new MFNode(), CHILD_NODE));
        rotation.set(addExposedField(SFROTATION, "rotation", new SFRotation(0.0f, 0.0f, 1.0f, 0.0f)));
        scale.set(addExposedField(SFVEC3F, "scale", new SFVec3f(1.0f, 1.0f, 1.0f), new SFFloat(0.0f)));
        scaleOrientation.set(addExposedField(SFROTATION, "scaleOrientation",new SFRotation(0.0f, 0.0f, 1.0f, 0.0f)));
        translation.set(addExposedField(SFVEC3F, "translation", new SFVec3f(0.0f, 0.0f, 0.0f)));
        bboxCenter.set(addField(SFVEC3F, "bboxCenter", new SFVec3f(0, 0, 0)));
        bboxSize.set(addField(SFVEC3F, "bboxSize", new SFVec3f(-1, -1, -1), new SFFloat(-1.0f)));
    }

Different fields are internally handled as integer values.
The variables center, children, rotation, scale, scaleOrientation, translation, bboxCenter and bboxSize are of type "fieldIndex", something like a readonly integer, that can be only set once.
There are NodeTransform memberfunctions to get and set field values. For example, the memberfunctions for the field "center" of class "NodeTransform" are:

SFVec3f * | center (void)
void | center (SFVec3f *value)
void | center (SFVec3f &value)
int | center_Field (void)

The memberfunctions "something_Field()" deliver the integer number of a field that is needed for example for a MoveCommand to move nodes in the scenegraph.

Functionality common to all Nodes (like writing a Node to a file (Node.write()) is in the class Node (file Node.h/cpp). All NodeNodeName classes are subclasses of the class Node.
Some of the memberfunctions of the class Node are virtual and can be overwritten by the NodeNodeName classes (for example, the class NodeScript need a special version of Node.write()).
Here is a list of important virtual Node memberfunctions:

- getType()
  deliver a value needed to identify different nodes. For example, the transform node deliver DUNE_TRANSFORM.
- write
  write the node to a VRML file.
- update
  update a node after a field change.
- setHandle
  change a node field from handles (e.g. white boxes in the Scene3DView, that can be moved around with the mouse).
- getHandle
  get the value of a handle.
- drawHandles
  draw the handle in the Scene3DView.
- preDraw
  do operations that prepare the drawing of nodes in the Scene3DView.
- draw
  drawing the nodes in the Scene3DView (and internally to find mouse hits).

Some geometry nodes (like ElevationGrid) are implemented as a subclass of MeshBasedNode. The MeshBasedNode class is used for geometry that can implemented as a IndexedFaceSet type of mesh. The MeshBasedNode class provides important virtual Node memberfunctions like draw. The creation of the mesh in a MeshBasedNode is done via the virtual function createMesh.
Some geometry nodes (like NodeSuperShape) are implemented as a subclass of MeshMorphingNode which is a subclass of MeshBasedNode by itself. A MeshMorphingNode can write a morphing animation of a IndexedFaceSet, when "File->Export As...->Export as &Pure VRML97..." or "File->Export As...->Export as VRML level &X3DV..." is used.

## VRML97 parser

Dune need to read and parse ("understand") VRML97 files.
This is done with using the tools lex/yacc (it looks like, the advanced tools flex and bison from the GNU project are needed).
The file lexer.l do the lexical analysis (detect things like "what is a string", "what is a number", "what is that VRML97 keyword").
The file parser.y do the grammatical analysis (detect and prove, if the tokens found by the lexical analysis form valid VRML contructions (like Node or ROUTE statements). If some tokens of the grammar are valid, the action part of the command in the parser.y file create the matching VRML Nodes, Numbers etc.

## Dangerous constructs

The buildin stringtype ("MyString") can be misleading, it act very pointerlike. For example be carefull about constructs like the following:

      MyString str = node->getProto()->getName();
      str += "something";

This do not only copy the name of a Proto of "node" to str and append "something" to it, it also appends "something" to the name of a Proto !

In this situation, it is better to use something like

      MyString str = strdup(node->getProto()->getName());
      str += "something";

or

      MyString str = "";
      str += node->getProto()->getName();
      str += "something";

## "Adding a new (scripted) geometry node to white_dune"-cookbook

- Select a name of the new node (here "Something")
- add a ID_NEW_SOMETHING to resource.h.m4, usually via adding a new m4 macro M4_ID(SOMETHING)
- Add

        MENUITEM "Something",                  ID_NEW_SOMETHING

  under

        POPUP "Scripted PROTOs (slow)"
             BEGIN

  and

            ID_NEW_SOMETHING      "Create a new Something Scripted PROTO\nSomething Scripted"

  to all src/dune.*.rc files. See the chapter about localisation for more informations about handling the needed language translations.
- add a DUNE_SOMETHING to the matching place (sorted by the alphabet) to the matching enum in Node.h
- add a

        _protos["Something"] = new ProtoSomething(this);

  in a matching place (sorted by the alphabet of the DUNE_SOMETHING in the list in Node.h) in Scene::Scene() and add

        #include "NodeSomething.h"

  to Scene.cpp
- copy a similar Node*.h/cpp to NodeSomething.h/cpp and change the fields/EventIns and draw, setHandle etc. functions.
  Do not forget the getType() function.
- in case the new node is always insertable (as usual geometry node) add a

        { DUNE_SOMETHING,       ID_NEW_SOMETHING, true, true },

  or insert

        { DUNE_SOMETHING,       ID_NEW_SOMETHING, false, true },

  to

        static NodeButton buttonsScripted[] = {

  in Windows.cpp
- Use gimp to include a new icon (16 pixels width) of your node (nodenames need to be sorted by the alphabet) into res/node_icons.bmp (or res_color/node_icons.bmp for UNIX type compilation with configure)
  Warning: DO NOT change the numbers of colors in this bitmap file !
  When you have gimp version 1.2 installed as "gimp", you can use the script "batch/inserticon.sh" under Linux/UNIX/MacOSX by typing

               sh batch/inserticon.sh DUNE_SOMETHING

  gimp will then open and select the matching node icons that has to be moved 16 pixels to left. Use "edit->cut" and "edit->paste" then move the icons to the left border of the gimp window. Draw your new icon in the new 16 pixels wide white gap.
- add a

              case ID_NEW_SOMETHING:
              CreateGeometryNode("Something");
              break;

  to MainWindow::OnCommand(int id) in MainWindow.cpp
- A scripted node makes only sense with a VRML97 PROTO statement. Put your PROTO into the docs/scriptedNodes directory.
- add the name of your NodeSomething.cpp file into the matching place in the src/Makefile.in file and to the M$Windows project.
- Do not forget the GPL license, which forces you to public somehow the complete sources, if you want to redistribute a modified version of white_dune...

The Implementation of a regular new (eg. X3D) Node is similar.

## Localisation: translating the program to foreign languages

It requires absolute no programming skills to translate the program to a foreign language, if the foreign languages uses ASCII characters:
you only need to copy the file "src/dune.english.rc" into a similar file, use a texteditor with search and replace und at end translate the strings in this file to the foreign language.

The problems when trying to translate the program to a foreign language with non ASCII characters (like chinease UTF8 characters) are untested/unknown.

To complete the task to create a new runnable program a compatible compiler is needed. Of course, this task can be done (after publicing the main translation file src/dune.something.rc) by a programmer later, it do not need to be done by the translator.
All "src/dune.*.rc" files are copied together into one src/dune.rc file during the run of "configure" and "make".
This means, that for creating a new runnable program, you need either a UNIX like system (e.g. Linux or MacOSX) or a bunch of unixtools:
m4, make, cat, grep and sh (e.g. bash or ksh).
A complete free/opensource installable collection of unixtools for M$Windows is called cygwin and is available for free from the internet.

For Translaton, first search the ISO 3166 two characters of your language (e.g. "en" for english, "de" for german, "it" for italian, etc...) and build the uppercase version of this characters (e.g. EN for english, DE for german, IT for italian, etc).

Second, select a src/dune.something.rc file. In the simpler case, do not select "src/dune.english.rc" cause this requires more complicated search and replace commands.

- In case of translating "src/dune.english.rc", you have to replace the following characters in the whole file:
  - IDR_ with IDR_DE_ for german, IDR_ with IDR_IT_ for italian etc
  - IDD_ with IDD_DE_ for german, IDD_ with IDD_IT_ for italian etc
  - IDS_ with IDS_DE_ for german, IDS_ with IDS_IT_ for italian etc
  Now search for the first occurance of STRINGTABLE DISCARDABLE in src/dune.english.rc and replace (starting at this point)
  - ID_ with ID_DE_ for german, ID_ with ID_IT_ for italian etc
- In case of translating a other "src/dune.*.rc" than "src/dune.english.rc", you simply have to replace the term _??_ in the whole file, where ?? marks the uppercase ISO 3166 two characters. E.g. if you translate "src/dune.german.rc" to "src/dune.italian.rc", you have to replace _DE_ with _IT_ in the whole file, thats all.

Third you need to translate all the strings in the new src/dune.something.rc file. A so called string is a term that starts with a " and ends with a "
For example, the translation of the line from src/dune.english.rc

        POPUP "&File"

to german language in src/dune.german.rc would result in

        POPUP "&Datei"

where the german word Datei is the translation of the english word File. The "&" sign marks the keyboard shortcut. The next character after "&" should not be ambient in the same level of a menu.

After the translation of the strings is ready, the translation step is ready. On a Linux/UNIX/MacOSX/cygwin system with the gawk (GNU awk) program you can use

    sh test/testmenus.sh

one the commandline to use some consistency testing of the new rc file.

The new file src/dune.something.rc can be now publiced (e.g. in a usenet group like comp.lang.vrml, or at the sourceforge site for the original dune project).

For a recompilation, you first need to extend the list of lanugages, white_dune understands.
Currently you need to extend the list of known languages in the file src/swt/include/languages.m4. E.g. to extend the list of known languages from english (empty default) and german (DE) in src/swt/include/languages.m4

    define(`M4_LANGUAGES_CONFIG',`
    DE,german')

to english, italian (IT) and german, then change the list to

    define(`M4_LANGUAGES_CONFIG',`
    IT,italian,
    DE,german')

or extent to english, italian and spanish (ES) and german, then change the list to

    define(`M4_LANGUAGES_CONFIG',`
    IT,italian,
    ES,spanish,
    DE,german')

Take care that the last language line (here with "DE,german") do not end with a comma.

It is also possible to change the yes/no strings in Linux/UNIX messageboxes. E.g. you extend the yes/no strings from english and german in src/swt/include/languages.m4

    define(M4_YES_english,"yes")
    define(M4_YES_german,"Ja")

    define(M4_NO_english,"no")
    define(M4_NO_german,"Nein")

with the yes/no strings of italian, you have to change src/swt/include/languages.m4 to

    define(M4_YES_english,"yes")
    define(M4_YES_italian,"si")
    define(M4_YES_german,"Ja")

    define(M4_NO_english,"no")
    define(M4_NO_italian,"no")
    define(M4_NO_german,"Nein")

The final step is rebuilding the needed files for compilation. On a Linux/UNIX/MacOSX/cygwin system, this is done automatically by using "sh build.sh"
(or "configure && make").
On other systems, at least a text editor and a port of the m4 program is required.
With the texteditor, copy all dune.*.rc files together and store the result in the file "dune.rc"
With m4 you need to execute the following commands in the src directory:
m4 resource.h.m4 > resource.h
m4 CommandlineLanguages.h.m4 > CommandlineLanguages.h

After recompilation (see the file INSTALL for details), the new language can be used with a commandline parameter. The name of the new commandline parameter is the minus sign followed by the second word in the new line in M4_LANGUAGES_CONFIG.
E.g. if you added "IT,italian," to M4_LANGUAGES_CONFIG, the new commandline parameter to switch to the italien language is -italien

All that have to be done now is to add the new commandline parameter to the documentation in the manpage file man/dune.1

## Localisation from a programmers point of view

When handling text messages from a programmers point of view, always try to use the function "swLoadString" to get a language related string (e.g. for a errormessage) from the "src/dune.rc" file. The first argument of the swLoadString file is a identifier, like IDS_INTERNAL_ERROR, which refers to the message in the default (english) language. To get the current language translation, add the term TheApp->getLang() to the idenifier, e.g . with swLoadString(IDS_INTERNAL_ERROR + TheApp->getLang(),...

As a programmer, take care about the fact, that each program code modification (e.g. addition of new menu items) in one of the src/dune.something.rc files requires the change of a all other "src/dune.somelanguage.rc" files.
Cause a programmer is usually not a multilingual genius, the addition of a new menuitem, icon tooltip or errormessage comes with a translation problem. There are two possible solutions: either use a dictionary/internet translation service like babelfish.altavista.com, or leave the english word in the src/dune.something.rc file and hope for modification by users.
To leave the line blank cause of a unknown foreign word is not a option, cause this can result in a crash of the program when used in this foreign language.
The addition of a new icon tooltip or errormessage also requires the inclusion of a new "#define" command which can be usually found in the resource.h file.
Do not change the resource.h file directly. The file resource.h is a autogenerated file, that could be overwritten at each run of the "make" command or "configure" command.

## class overview

The name of most sourcefiles in the "src" directory is identical to the name of the major contained class.

The following class/filenames have special meanings:

- NodeSomeNodeName:
  Implement details for the VRML Node "SomeNodeName"
- SomethingDialog, SomethingWindow, SomethingView:
  Implement details for the graphical user interface (GUI)
- SomethingApp:
  Implement details for data global to the whole application
- SomethingCommand:
  Implement details for sending internal commands
- SFSomething, MFSomething:
  Implement details for VRML datatypes

If doxygen is installed, a class hierarchy of white_dune can be produced by typing

             make documentation

and can then be found here.