Game Development Reference
Figure 12.4 Visualization of a driving scene using a head-mounted display. (Illustration: PSA Peugeot
Citroën, with permission)
It is necessary to know whether the vertical axis of the virtual location always remains
identical to the vertical axis of the real location where the observer is situated. In the
case of an observer whose head movements are registered, a BSA should restrain the
vertical of the virtual location for it to remain unchanged if there is any apprehension
that the user might tilt his head involuntarily in front of the screen or in the head-
mounted display. Another question to be asked is regarding the position of the eyes of
the observer: will they always remain on the same virtual horizontal level? If not, for
example, for supporting complex mechanical devices (the fourth case of observation),
only the head-mounted display would be suitable.
Generally speaking, it is necessary to analyse the inevitable movements 3 of the
reference point linked to the observer's head with respect to a fixed reference point in
the virtual world.
12.2.3 Acoustic observation
Acoustic observation is quite simple to analyse on the basis of functional I 2 .Ifa
monophonic or stereophonic sound of the virtual environment is to be provided, there
are nomajor technico-economic or ergonomic difficulties. On the other hand, technical
solutions are found in specific hardware and with help from specialists if a spatial or
3D sound is to be created, i.e. sounds from sound sources located in 3D space.
3 Inevitable in relation to functional I 2 .