This series of scenes follow on from the earlier simple tunnel scenes  and
use a combination of tunnels with active walls to simulate the  action  of
a "transmat" device.  The name transmat is used in Doctor Who as a generic
term for any teleportation device. In the television series such a  device
causes an object, or person,  to disappear from one location and appear in
another. This may be accompanied by varying special effects,  one of which
takes the form of a simulated "space-time tunnel" and it is this  kind  of
effect that is simulated by this series of scenes.  These  scenes  do  not
attempt to reproduce the transmat effects from any particlar  episode  but
only some sort of space time tunnel that could be used for a transmat.

The basic effect is obtained by nesting two or three tunnels each of which
is generated by a tunnel shader using the output of some other  shader  as
the texture for the tunnel walls. In particular a tunnels having firey and
watery walls are used with the watery tunnel being used  for  the  initial
"take off" and "landing" stages of the teleportation and the firey  tunnel
used for the main transportation phase.  These  tunnels  are always partly
translucent and are faded in and out as the teleportation progreses.

In addition to the fiery and watery tunnels a third tunnel is used, again
using the output from another shader to provide the texture for the walls
of the tunnel. The effect produced is of a series of widely spaced energy
discharges that travel along the tunnel during  the  main  transportation
phase.

Another shader is used to provide an animation of the  controls  used  by
the unseen transmat operator. The image of these controls is faded in and
out so that they only obscure the view for relatively  short  periods  of
time during the take off and landing phases of the teleportation  events.
This shader, Daniel Burke's Time Coordinates, simulates a set of controls
seen in the Doctor Who episode The Name of the Doctor.

The activity of the tunnels used to model the operation of  the  transmat
is used to partialy hide the fading in and out of a series of  background
images that represent th locations that the performers are transported to
and way from.

Because these scenes use multiple shaders and multiple background  images
they can stress the capabilities of low end systems.  For  this  reason a
number of variations of the scenes are provided. These divide into groups
which provide increasingly complex transmat simulations with the Transmat
A series being the simplest and the Transmat C series the most complex.

Each of the Transmat A, B and C groups  of  scenes  comprises  individual
scenes involving various numbers of  teleportation  destinations,  though
they all start with the same strip club scene from which the performer is
lifted. These scenes fall into two sets, those in which the teleportation
destinations are fixed as various locations within a beach resort  and  a
second set in which the teleportation destinations are selected at random
from a larger set of backgrounds.

In the case of the beach resort destinations I like to think of them as a
sequence of destinations that first of all teleport the performer to  the
resort and then gradualy home in on a particular pool side location,  but
nce this has been achieved the transmat develops a fault and continues to
teleport the poor subject from place to  place,  including  back  to  the
original strip club stage.  In  the  case  of the random destinations the
scenario is more like some external agency is attempting  to  snatch  the
doctor's companion,  but  is foiled by the doctor but only at the expense
of her being shuttled endlessly from place to place.

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The backgrounds are taken from two directories, that used for the initial
background contains only backgrounds corresponding to  the  the  supposed
initial location - which is assumed to be a strip club - while that  used
fot the transmat destinations are taken from a different directory.  This
is done so that the initial backgound is not accidently also  chosen  for
one of the random destinations.

Currently there is only a single image in the initial locations directory
but it is hoped that add alternative strip club settings will be added at
some point in the not too distant future.

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The way in which the backgrounds are faded in and out means that at  some
times no destination background is faded in.  At  these times the initial
background will be visible  (corresponding perhaps to the Doctor managing
to temporarily return his companion to her starting point).  However, for
the longer sequences these occasions would be quite rare if  all  of  the
first N "time slots" are allocated destination backgrounds.  In  order to
increase the frequency of returns to the initial location when using  the
longer random sequences one or more of the time slots are no used for any
destination.

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With a change of location every 80 seconds it takes about 20 minutes to
visit each of twelve transmat destination,  including  three returns to
the initial location. Therefore if you want to see the full sequence of
locations for one of the longer scenes you will have to ensure that the
minimum delay between scenes setting on the fullscreen settings tab  is
set to an adequately long period.

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Another way to look at this series of scenes is that they are just simple
slideshows of background images with a rather complex transition effect.

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