Graphics Reference
In-Depth Information
The users can roam the three-dimensional model of the virtual gymnasium such as
walking through the virtual gymnasium, observing and experiencing it at different
positions through the technology of “picture pick-up.” The nut is how to acquire the
information about the mouse click on the seat visually in the virtual environment. So,
the Screen-to-World algorithm has to be correctly implemented based on the basic
principle of scenography projection.
The main functions of the implemented roaming system of the stealth model in-
clude are: (1) interactive roaming, that is,the users can control the roaming path
through the mouse and the key by themselves; (2) automatic roaming, that is, the
users can define the roaming path on the plan model, then the roaming system will
walk through the stealth model according to the predefined path without human inter-
vention; (3) the record and playback of the roaming path, that is, the roaming path
used in the above-mentioned function will be recorded and can be played back for
replay. It is obvious that the implementations of these functions rely heavily on the
multi-dimensional information integration of virtual gymnasia which is of particular
interest in this context.
4
The Multi-dimensional Information Integration
of Virtual Gymnasia
The Plan View Display (PVD) and the stealthy view are the two most frequently used
means for information display. The former will be helpful to build the global aware-
ness of the virtual gymnasium and has low requirements for the hardware while it is
difficult to represent the solid gymnasium vividly. The latter is good at representing
the local awareness of the virtual gymnasium with restrictions to the limited compu-
ting speed and the screen size, thus, roaming is often essential for practical operations.
Therefore, if the PVD, stealthy view, text, picture and sound can be seamlessly inte-
grated, plus the interactive means, the multi-dimensional information space will be
presented to the observers who will be inspired to acquire the knowledge and led to
the creative thinking.
With the development of the technologies of the computer graphics, the three di-
mensional modeling, the rendering and the multimedia, it is possible to implement the
multi-dimensional integrated information system [5] [6]. As for the virtual gymna-
sium, the principle of the interaction between the plan model and the stealth model
can be described in Figure 5: the viewpoint in the stealth model will be automatically
changed to the corresponding position pointed out on the plan model by the mouse, at
the same time, the current position will be automatically displayed on the plan model
accordingly when users select the specific space element on the stealth model. In
other words, the two views are correlated to each other.
Note that the underlying two-dimensional and three-dimensional databases store all
the required spatial and attribute data. They are the key to the multi-dimensional in-
formation integration of virtual gymnasia and can be constructed upon the basis of the
spatial databases or the relational databases.
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