What is WTK R6?

WorldToolKit R6 is a portable, cross-platform software development system for building high-performance, real-time, integrated 3D applications for scientific and commercial use. The WTK library has more than 900 high-level functions for configuring, interacting with, and controlling real-time simulations

Object-orientated structure

WTK is structured in an object-orientated manner, although it does not use inheritance or dynamic binding. WTK functions are object-orientated in their naming conventions WTK functions are grouped into classes

• Classes include:
  • Universe
  • Geometry
  • Viewpoints
  • Sensors
  • Paths
  • Lights
    
• Functions are included for:
  • Device instancing
  • Display setup
  • Collision Detection
  • Loading geometry from files
  • Dynamic geometry creation
  • Object behavior
  • Rendering control
  • 2d graphics interfaces

WTK Basics

WTK is so named because your applications can resemble virtual worlds Object can have real world properties and behaviors. Worlds are controlled by a variety of input devices 2d mice - 6d sensors. Users experience worlds through a computer display or by using HMDs. Simulations are built by assembling NODES into a hierarchy called a SCENE GRAPH.

• Nodes
  • The smallest element in a scene graph
  • Used to build a scene graph by arranging in a hierarchy
    

• Scene Graph
  • A hierarchical assembly of nodes
  • Dictates how the scene is rendered to the output device
  • All efficiencies of state preservation
  • Stack-orientated architecture
  • Creates an efficient visual database
  • Increased performance
  • Control
  • Flexibility
  • Hierarchical object culling
  • Efficient use of transform information
  • Level of detail switching
  • Allows multiple windows each with its own scene graph

Naming Conventions

• Each class of object had a typedef defining an object of that type:
  • WTsensor is a sensor object
  • WTuniverse is a universe object
  • WTviewpoint is a viewpoint object
• Objects are always dealt with through the use of pointers
• Objects are opaque forcing data abstraction
• State of an objects is accessed through get and set functions
• All methods of a give class have a naming convention that begins with the class name such as:
  • WTuniverse_new
  • WTviewpoint_setposition

A Sample WTK application

/* a sample WTK application code */
/* include this file with all wtk applications */
#include "wt.h"

/* function declarations */
void actions(void);

/* globals */
WTsensor *spaceball = NULL;

int main(void)
{

/* initialize the simulation manager */
WTuniverse_new(WTDISPALY_DEFAULT, WTWINDOW_DEFAULT);

/* load a default lighting file */
WTlightnode_load(WTuniverse_getrootnodes(), "lights");

/* load a geometry from a file *.
if (!WTnode_load(WTuniverse_getrootnodes(0, "mygeofile", 1.0f);

/* initialize a spaceball sensor */
spaceball = WTspaceball_new(SERIAL1);

/* set the universe action functions */
WTuniverse_setactions(actions);

/* scale the sensor to the speed of the universe */
WTsensor_setsensitivity(spaceball, 0.1f * WTnode_getradius(WTuniverse_getrootnodes());

/* attach the sensor to the viewpoint using a motion-link
WTmotionlink_new(spaceball, WTuniverse_getviewpoints(), WTSOURCE_SENSOR, WTTARGET_VIEWPOINT);

/* ready the universe for the simulation loop */
WTuniverse_ready();

/* Enter the main simulation loop */
WTuniverse_go();

/* Exit the application and clean up */
WTuniverse_delete();

/* return */
return 1;

}

/* The action function */
void actions(void)
{

/* stop by pressing button one on the spaceball */
if (WTsensor_getmiscdata(spaceball) & WTSPACEBALL_BUTTON1)
WTuniverse_stop();

} /* end actions */