Virtual Reality Madness/VRMAD96_ONE.ISO/vistapro/manual/ch4.txt

Text File | 1993-08-02 | 41KB | 934 lines

_____________________________

Chapter 4
Vistapro User Manual
_____________________________

CONTROL PANELS


The Vistapro Control Panels are split into three main sections,
which we call the Upper, Middle and Lower Control Panels. In
addition, there is a Color Control Panel.

The map in the window represents the landscape area you loaded
into Vistapro. The small black + symbol on the map is the
Target. The small black box symbol is the Camera.

UPPER CONTROL PANEL
-------------------
The target represents the point at which you are aiming the
camera. Its location is measured in meters from the lower left
hand corner of the topographic map and in meters above sea
level. After selecting the Target button on the Control Panel,
you can place the mouse pointer anywhere over the landscape and
click the left mouse button, setting a new target position in
the X and Y direction. The Z, or height value, is set to the
elevation of the landscape at that X-Y coordinate. That is, the
Z value in the target represents the actual elevation of the
landscape at that point.

As an alternative, you can place the target precisely by
entering locations directly into the X, Y and Z numerical
gadgets. To change a value, select the appropriate numerical
gadget by clicking the left mouse button in the numerical
gadget. Use normal editing techniques to change the values.
(Backspace, delete, etc.)

You may also delete the entire contents of the gadget by
pressing the SPACE bar. This works in all the numerical gadgets
in Vistapro. When finished editing press the ENTER key or the
left mouse button to accept the new value. Press the ESCAPE key
or the right mouse button to stop editing and restore the
original value. See also Locking Functions.

Camera
------
The camera represents the location of a hypothetical camera
used to take a scenic picture. Its location is measured in
meters from the lower left hand corner of the topographic map
and in meters above sea level. The X coordinate is from left to
right on the topographic map. The Y coordinate is from bottom
to top on the topographic map, and the Z coordinate is in
meters above sea level. Select Camera on the Control Panel.

By placing the pointer anywhere over the landscape and clicking
the left mouse button, you can select a new camera position in
the X and Y direction, and the Z or height value changes with
the elevation of the landscape. The Z value of the camera is
set to 30 meters above the landscape. Alternatively, one can
place the camera precisely by entering locations directly into
the X, Y and Z numerical gadgets.

To change a value, select the appropriate numerical gadget by
clicking the left mouse button inside the gadget. Use normal
editing techniques to change the gadget values (backspace,
delete, etc.). Delete the entire contents of the gadget by
pressing the SPACE bar. This works in all the numerical gadgets
in Vistapro. When finished editing press the ENTER key or the
left mouse button to accept the new value. Press the ESCAPE key
or the right mouse button to stop editing and restore the
original value. See also Locking Functions

Locking Functions
-----------------
Other tools that you can use with both the camera and target
functions are the X, Y and Z locks. You can use the locks when
you want to restrain the target or camera from moving in one or
more directions. For instance, if you want to move the camera
to a new location on the landscape without changing its
altitude, you could depress the Z lock and then click on a new
camera location. You will see that the X and Y coordinates of
the camera have changed but that the Z value has remained the
same.

Of course there are two other ways of achieving this same
result: you could simply type the new X and Y locations into
the camera X and Y numerical gadgets, or you could click the
mouse on the new camera location (with the Z lock not set) and
then type in the desired altitude. Vistapro will restrain both
the camera and target X, Y, and Z values as long as the locks
are depressed.

dR   dR displays the distance in meters between camera and
     target. This distance is the radius from the target. You
     can use this value to step closer to or away from the
     target - just as one might do when taking a photograph.
     When you type in a new distance value Vistapro will change
     the camera's X, Y, and Z coordinates to match the desired
     distance as well as it can. The Bank, Heading, and Pitch
     values will not change.

dX   dX displays the difference between camera and target X
     dimension values. The user can change this value by
     entering a new value in the dX numerical gadget. Changing
     this value moves the camera to reflect the new distance.
     The Heading and Pitch of the camera may also change to
     keep the camera pointed at the target.

dY   dY displays the difference between camera and target Y
     dimension values. The user can change this value by
     entering a new value in the dY numerical gadget. Changing
     this value moves the camera to reflect the new distance.
     The Heading and Pitch of the camera may also change to
     keep the camera pointed at the target.

dZ   dZ displays the difference between camera and target Z
     dimension values. The user can change this value by
     entering a new value in the dZ numerical gadget. Changing
     this value moves the camera to reflect the new distance.
     The Heading and Pitch of the camera may also change to
     keep the camera pointed at the target.The following
     descriptions use an airplane as a model to explain axes.

Bank
----
Bank controls the rotational angle of the camera around its
longitudinal axis. Imagine an airplane. You can describe the
longitudinal axis as an invisible line drawn from the tail of
the airplane to the nose. Any rotation that causes one wing to
dip and the other to raise is a rotation around the
longitudinal axis. A positive rotation around this axis would
cause rotation in a clockwise fashion as viewed from the tail.
The left wing would raise and the right wing would lower. Note
that when the camera rotates clockwise the view that is
rendered will appear to have rotated in the opposite direction.

Head
----
Heading describes the rotational angle of the camera around its
Z axis relative to the landscape. Imagine an airplane . You can
describe the Z axis as a line drawn from the top of the
airplane to its bottom. Any rotation around this axis causes
the airplane to turn right or left. A positive rotation causes
the airplane to turn right.

Pitch
-----
Pitch is the rotational angle of the camera around its wing
axis. Once again, imagine an airplane. A line drawn through the
wings from the left side of the airplane to the right side
describes the pitch axis. Any rotation around this axis causes
the airplane to move the nose either up or down, with a
positive rotation causing the nose to go up.


MIDDLE CONTROL PANEL
--------------------

Sea
---
By setting the sea level, you can sink the landscape into the
sea to that level. All points below this level become sea level
(0 meters), and all points above this level have that value
subtracted.

For example, if you select 1000 meters as sea level, all points
below 1000 meters will sink to 0, 2000 meters will sink down to
1000 meters, 3000 meters will sink to 2000 meters, etc.Vistapro
will erase rivers and lakes (if present) when it generates a
new sea level. Vistapro will need to color and shade the
landscape again.Vistapro has a button for selecting sea level.
You click on the Sea button and then select the level by
clicking on the topographic map. You can specify the Sea level
explicitly by typing the value into the numerical gadget
immediately below the Sea button (See also Waves).

Tree
----
You can use the Tree level button to set the timber line, the
altitude above which there are no trees. The timber line is a
"fuzzy" value. Just as in nature, some trees will appear above
the tree line and some bare areas will appear below it.

Vistapro's AI (Artificial Intelligence) rules will compensate
for features of the landscape. Trees generally will not cover
the face of a cliff even though the entire cliff may be below
the tree line. Trees may grow upward into a valley (more water
is available at the bottom of a valley) and a ridge will tend
to be devoid of trees (ridges tend to dry out from exposure to
the wind).

If the DrwTre (draw tree) button is not selected Vistapro will
not actually draw the trees, it will just use the tree colors
to color the ground.You can use the Tree button to select the
tree level. Depress the Tree button and then click on the
topographic map at a location which has the desired altitude.
You may also numerically specify a tree level by typing a value
into the numerical gadget located below the Tree button.

Snow
----
The Snow level is the lowest elevation where Vistapro will
cover the landscape with snow. The AI rules in Vistapro use
this value to calculate where to use the snow colors. Vistapro
will compensate for cliffs, ridges, valleys, rivers and lakes
in an attempt to mimic natural snow cover.Snow colors don't
have to be the colors of snow.

You can use any colors you like--just keep in mind that the
snow colors will be placed on the landscape following the AI
rules for snow. For instance, you can set the snow colors to
shades of gray to make mountain tops look like barren rock. The
barren rocky areas will appear to flow down into valleys just
as snow would.

You can use the Snow button to select the snow level. Depress
the Snow button and then click on the topographic map at a
location which has the desired altitude. You may also
numerically specify a snow line by typing a value into the
numerical gadget located below the Snow button.

Haze
----
In the real world, the farther away an object is, the more it
is occluded by the atmosphere. The haze function in Vistapro
simulates this effect, adding to the three-dimensional feel of
the resulting image.

You can specify how thick the haze is by changing the Haze
value in Vistapro. (You can also change the color of the haze--
see chapter 6, Color Control Panel.) You enter the Haze value
by entering a number in the numerical gadget below the Haze
button.

* A value of 0 will completely eliminate the haze effect
* Small values (below 100) will give very little haze
* Medium values (100-1000) will give medium haze
* High values (over 1000) will create very thick fog.

You can also "automatically" calculate the haze value by
pressing the Haze button. Vistapro will generate a value based
upon the distance between the camera and the target. The closer
the two are, the thicker (higher value) the haze.

We tried to arrange it so that setting the haze value this way
generates haze that first becomes significant at distances
about the same as that between the camera and target.

Lake
----
The lake function adds lakes to a landscape. Select Lake on the
Control Panel. Then, using the mouse, place the pointer on the
landscape at the lake level desired, and click the left mouse
button.

Example: If one places the pointer in a shallow valley at 2100
meters, water will begin to fill the valley until it reaches
the 2100 meter mark, as it would in nature.

If there is any portion along the edge of the valley that is
below the 2100 meter mark, water will spill out of the valley
and begin to flood other parts of the landscape. This may not
be the desired effect, and it should be kept in mind when using
the Lake function.

If uncertain about landscape heights, move the mouse pointer
around any suspect areas watching the Z value on the status
line. Then find the lowest point in the pass to determine the
maximum safe altitude for creating the lake. Lake generation
can be aborted by pressing the ESCAPE key or the right mouse
button while the lake is being generated.

To create a lake, press the Lake button and then click on a
starting point on the topographic map. You will see the lake
being created on the topographic map in black. Once the lake
has been completed the black lake will be redrawn in blue.

River
-----
Vistapro's River function creates rivers which flow downhill
from the selected starting point. If a river reaches a
depression it will slowly fill it (creating a pond or lake)
until the lake overflows.

The river will continue flowing down hill until it reaches the
ocean or the edge of the topographic map. You may stop the flow
of a river by pressing the ESCAPE key or the right mouse
button. Although you can always fill a lake using the River
function and wait until the lake fills up, it is generally
faster to fill lakes using the Lake function.

To create a river, press the River button and then click on a
starting point on the topographic map. You will see the river
being created on the topographic map in black. Once the river
has been completed the black river will be redrawn in blue.

If you start a river on an existing river or lake, the river
will continue until it reaches sea level or the edge of the
topo map. A new river (one started where there was not
originally a river or lake) will also stop at any existing
water. This allows you to create many tributaries to a river
without the main river getting very wide and deep.

Of course, if you want the main river to significantly widen,
start a new river on top of the old one as many times as you
like. It will grow wider with each iteration.You generally will
want to start rivers at the head of a valley, but it is
possible to start a river anywhere on the topographic map.

Smooth
------
The Smoothing function smooths or erodes the landscape,
removing the harsher, more jagged edges of hills and mountains.
Smoothing often improves the appearance of landscapes, and it
is especially useful when dealing with fractal landscapes. You
should use the smoothing function sparingly with DEM files if
data integrity is important, as it distorts data.

Pressing the Smooth button on the Control Panel will invoke the
smoothing function. This is a repeatable, refining function,
meaning that it can be run over and over again, smoothing
(eroding) the landscape more on each pass.

Smoothing is also used to obtain snow covered peaks. Because of
the design rules of the AI algorithms, and as is also true in
nature, it is very rare that the summits or peaks of mountains
are completely snow covered. It is more often the case that due
to the steep nature of the cliff faces and other contributing
aspects, such as wind and snow weight, snow does not cover the
peaks of most mountains. However, since it may be desirable
artistically to create a completely snow-covered mountain,
smoothing the mountains will often give this effect.

Enlarge
-------
The enlarge function allows you to select a portion of the
landscape and enlarge it to fill the entire topographic area.
The intermediate data points are either filled with the average
of the points around them or filled with duplicates of the
nearest point .

To invoke this function press the Enlarge button. You will then
see a box that follows the mouse cursor around the screen.
Place the box over the section that you want to enlarge and
press the left mouse button. Vistapro will open a requestor
near the top of the screen asking you to select either the
Interpolate (average) or Duplicate mode. Select the desired
mode and the area inside the box will be enlarged to fit the
entire topographic area. Any rivers, lakes, or oceans will be
lost.

The differences between the two modes is best described by a
diagram. Consider the side of a small hill viewed from a cross-
section; in Interpolate mode, the hill will double in size in
all dimensions and the side of the hill will remain smooth; in
Duplicate mode the hill will also double in size, but it will
become stepped:


Original data:     \
                    \____



Interpolate mode:  ____
                       \
                        \
                         \
                          \___
"in between" data is the average of the points around it.



Duplicate mode:    ───┐
                      │
                      └──┐
                         │
                         └───
"in between" data is the same as the points near it.

Waves
-----
Vistapro can generate waves on the sea. To enable this feature,
select Waves from the main control panel before creating the
sea. To deselect the waves feature, re-select the Waves button.
When you enable waves, Vistapro will generate them along with
any new sea that is generated. You can add waves to an already
generated sea by selecting the Waves function and setting a new
sea level, or the same sea level (value 0). While Vistapro is
generating waves, it displays a message on the status line.

Vistapro generates waves (if specified) only when a new sea
level is set, both on fractal and real-world landscapes.

DrwTre
------
Vistapro has two types of trees that it can draw while
rendering. Vistapro draws the trees only if the DrwTre (Draw
Tree) button is depressed. When you press the button a
requestor will appear at the top left corner of the screen.
From it you specify the size and type of trees to draw.

The size is specified by the numerical gadget at the center of
the requestor. You must select the size before the type since
pressing either of the type buttons will close the requestor.
Good sizes range from 20 to 80 meters. Very small trees may
appear too sparse; very large trees will be distorted or
overwritten by subsequent polygons of the landscape.

After selecting the tree size (or accepting the default) select
the type by pressing either the Pine or Oak button. Pine trees
will have roughly triangular shapes like a Christmas tree. Oak
trees will have roughly round shapes.

Trees may be drawn anywhere that TREE1 through TREE4 (see CMap
section) colors are used. In addition the number of trees drawn
is affected by the TreDns (Tree Density) setting.Trees are
drawn using TREE1 through TREE4 colors, plus a small randomizer
so that they are not all the same color. You cannot select the
brown shades Vistapro will use for the tree trunks. The ground
underneath trees is drawn as a slightly darker shades of BARE1
through BARE4.

Trees can take a very long time to draw. Depending on how many
trees are drawn, trees may take more than twice as long to
render as the same scene without any trees for Vistapro to
draw.

LckPal
------
Vistapro renders pictures using the PC's 256 color modes.
Vistapro calculates the best 256 colors to use just before
rendering each image. The colors it picks are based on the
colors in the landscape, the current Contrast and Exposure
settings, and the Haze colors and value. Calculating a new 256
color palette can be time consuming (about 40 seconds on a 20
MHz 386) so we have given you the ability to lock the color
palette.

When the palette is locked Vistapro will continue to use the
last palette generated. All succeeding images will be drawn
with that palette until the color palette is unlocked. Locking
the palette is especially useful when previewing an image,
playing with the haze settings or the Color Map. When you are
ready to render the final image, unlock the palette so that
Vistapro will generate the best possible palette for that
image. The palette is locked when the LckPal button is
depressed. It is unlocked when the button is up.

CMap
----
You can select the CMap button to display and activate the
Color Control Panel. See Color Control Panel for more
information.

Poly
----
Vistapro produces 131,072 polygons at its finest resolution.
The Polygon Size function controls the relative coarseness of
the landscape image. A size of 8 generates 1/64th as many
polygons (1/8th on each axis) as a size of 1, and they are 64
(8 x 8) times as large. That is, a landscape can consist of
131,072 size 1 polygons, 32,768 size 2 polygons, 8192 size 4
polygons, or 2048 size 8 polygons.

You can use the larger polygons to generate quick previews of
landscapes. When you are happy with your camera and target
placement, use smaller polygons. The smaller the polygons, the
longer it takes to generate the image. The larger the polygon
size number, the less detail that will show up in the image,
because Vistapro is displaying only a fraction of the original
data.

The lower resolutions (higher poly number, i.e. 4, 8) are
useful for quick test renderings to check for landscape color,
light placement, proper framing and exposure settings.

TreDns
------
TreDns (Tree Density) controls how many of the polygons
assigned TREE1 through TREE4 colors will also have trees drawn
on them. Useful values range from 0 to 300 with low values
giving low tree densities, high values giving high densities.
Values below 0 are treated the same as 0, values above 300 are
treated the same as 300. A value of 150 will result in one half
of the TREE colored polygons having trees rendered.

To change the Tree Density value, click on the numerical gadget
immediately below the TreDns label and type in a new value.
Press ENTER when finished.

Dither
------
Vistapro generally colors landscapes by altitude. The lowest
altitudes are colored with TREE1 through TREE4 colors, middle
altitudes are colored with BARE1 through BARE4 colors, and the
highest altitudes are colored with SNOW1 through SNOW4 colors.
Each of the 130,000 triangles that make up the landscape is
assigned a color, based on its altitude and several other
factors.

The Dither value sets the fuzziness of the division between
color bands in Vistapro. A setting of 0 will give the tree-line
and snow-line very sharp boundaries. The default setting of 200
gives a moderate amount of dithering of the colors. A large
value like 1000 will make the colors so dithered that there is
no visible relationship between altitude and color. To set this
value, click the mouse pointer on the Dither numerical gadget
on the Main Control Panel. Change the number from the keyboard
and press ENTER. Useful values range from 0 to 1000.

VScale
------
Vistapro allows you to vertically re-scale any landscape.
Typing a number into the Scale numerical gadget will cause
Vistapro to scale the landscape as requested. For example, if
you type in 2.0, Vistapro will stretch the landscape out
vertically so that mountains are twice as tall, etc. Values
between 0.0 and 1.0 will cause Vistapro to flatten the
landscape. Values below 0 cause the landscape to flip over
(valleys become ridges, mountains become pits) before Vistapro
scales them. The number typed in always results in a landscape
which is that value times the original landscape. The user can
save landscapes after scaling.

You can generate some interesting effects with the scaling
function. You can flip landscapes upside down by using negative
values. Scaling mountains so that the top will exceed 32000
meters and then scaling it back down to normal will result in
mountains with big pits or calderas. Scaling to very large
values can even cause several layers of this effect. The result
shows a mountain inside a collapsed mountain inside a collapsed
mountain. Scaling mountains down until they are very small and
scaling them back up will result in stepped mountains.

Main
----
The Main button enables and displays the Main Lower Control
Panel. See Main Lower Control Panel for details.

Lens
----
The Lens button enables and displays the Lens Lower Control
Panel. You can use this to select the type of lens the Camera
is using. See Lens Lower Control Panel for details.

Frac
----
The Frac button enables and displays the Fractal Lower Control
Panel. You should use this when generating random fractal
landscapes. See Fractal Lower Control Panel for details.

Light
-----
The Light button enables and displays the Light Lower Control
Panel. Use this when selecting the direction and intensity of
the light source. See Light Lower Control Panel for details.


LOWER CONTROL PANELS
--------------------
The Lower Control Panels consist of four separate Control
Panels overlaid on a common space.

MAIN LOWER CONTROL PANEL
------------------------

Blend
-----
Blend helps reduce the coarse texture of distant parts of the
landscape. If you select the Blend button, Vistapro will draw
each polygon with a weighted average color of that polygon and
the three polygons that border it. This reduces the aliasing of
distant polygons. It also reduces the color saturation of
polygons, so its use is optional.

Gshade
------
Gouraud shading produces smooth looking surfaces without
obvious triangles. It requires about 50% more rendering time.
Gouraud shading gives a brush like feeling to the landscape, as
if an artist painted it using oils, rather than the computer
playing with numbers. Besides filtering out large polygons, it
adds mood to the landscape. The foreground may appear blurry
with Gouraud shading.

Range
-----
The range value allows you to clip away parts of the landscape
which are farther away than the range value. For example, if
the range value is set to 1000, Vistapro will not draw parts of
the landscape farther away than 1000 meters. The primary reason
for this function is to show only the parts of the landscape
very near the camera, making sure that something is not
blocking the view. You don't want to wait thirty minutes for a
picture to render just to find out that a tree completely
blocks the view.

The value 0 is a special case; it disables the Range function.
Otherwise the value represents the distance from the camera, at
which the landscape is clipped away. Values below 100 are
usually not useful. The sky and horizon are not affected by the
Range function.

The range function can be used to generate a special effect
while executing a script file. As the camera moves around the
landscape, only the parts of the landscape near the camera
(within the Range) will be visible.

Texture
-------
Vistapro can add additional texture to nearby polygons by
breaking them into smaller pieces and drawing each of the
pieces as slightly different shades. This adds artificial
detail to nearby areas. There are four different levels of
detail:

    * Off
    * Low
    * Medium
    * High

They are selected by the "O", "L", "M", and "H" buttons below
the Texture label. The higher the detail level the longer a
picture will take to render.

PDthr
-----
Dithering at the pixel level increases the apparent number of
colors in the display. Vistapro uses a dithering method which
allows you to set the amount of dithering used within the
display. It can be set anywhere from no dithering to so much
dithering you can no longer recognize the picture. Normal
values will range from 0 (no dithering), to 100 (a little
dithering), to 300 and above (significant dithering). When a
new dither value is entered, Vistapro prompts for ordered or
random dithering.

Render
------
This starts the generation of a new picture using the current
settings in the control panels. Vistapro performs several
functions while rendering. It displays its progress above the
topographic map in a status window. For most functions, there
is a continuously updated status count, so that you can monitor
Vistapro's progress. (See Vistapro Status Window for more
information.) You can abort the rendering process by pressing
the ESCAPE key or by pressing and holding down the right mouse
button until the rendering stops.

View
----
When rendering is complete Vistapro waits for you to press
either mouse button or the ESCAPE key. It then redisplays the
control panel and topographic map. If you want to see the same
picture again you can view it by pressing the View button. The
picture will remain visible until you press either of the mouse
buttons or the ESCAPE key.


LENS LOWER CONTROL PANEL
------------------------
The camera lens feature represents the lens type of Vistapro's
imaginary camera.

Wide: The wide angle lens gives a 90 degree field of view. It
      allows you to see a wide area with minimal spherical
      distortion. The wide angle lens has a zoom value (similar
      to the focal length of a real camera) of 16.

Zoom: The Zoom lens has about half the field of view of the
      wide angle lens (about 45 degrees), or you can think of
      it as having twice the magnification. It allows you to
      zoom in on the target. Very little distortion is
      noticeable. The Zoom lens has a zoom value of 32.

Zoom Value: The Zoom value is similar to the focal length of a
            real camera. It represents the width of the field
            of view or the amount of magnification. The lower
            the Zoom value is, the wider the field of view. The
            higher the Zoom value is, the narrower the field of
            view and the greater the magnification.

            The lowest valid Zoom value is 1. This is an
            extremely wide angle lens with severe spherical
            distortion. Values below 8 are generally
            impractical but fun to try. You can set the Zoom
            value as high as 30,000, but such high numbers are
            only useful when the camera is very far from the
            landscape (a million meters or so). You will
            probably usually use Zoom values from 16 to 100.


FRACTAL LOWER CONTROL PANEL
---------------------------

Random
------
Random Landscape Generation allows creation of a vast number of
completely artificial landscapes. Vistapro supports over four
billion random fractal landscapes. Each different number in the
Fractal numerical gadget represents a different landscape. You
can use negative numbers. Using a number such as -1,231,541
will create a different landscape than its positive counterpart
1,231,541. Select Random on the Fractal Lower Control Panel.
Notice that a new number has appeared in the numerical gadget.
The software will then proceed to create a new landscape. If
this landscape is one which you may want to use again, be
certain to write down the number so that you can recall it
again, or save the landscape, using the Save DEM Menu Item.

To recreate a desired landscape, simply reenter its number in
the numerical gadget and Vistapro will create the same
landscape again. This method conserves disk storage space much
more efficiently than saving the entire landscape as a DEM
file. Alternatively, enter any number desired into the
numerical gadget and explore landscapes in this fashion.
Various methods include using special dates such as birthdays
(minus hyphens or slashes, i.e.. 52262 not 5-22-62), holidays
and anniversaries. Keep a list of numbers for those landscapes
that prove to be interesting so that you can share them with
other owners of Vistapro.

Like the fingerprints of the four billion inhabitants of this
planet, some Vistapro scenes may look similar, but, upon closer
examination, each one is individual and distinctive.

Island
------
There are two modes for generating fractal landscapes, Island
and Floating. In Island mode the four edges of the fractal
landscape are at the same altitude. This allows you to create
islands by setting the sea level higher than this edge
altitude. It also will create seas surrounded by land. See the
Sea function for details on its function.

In floating mode, the four edges of the landscape are allowed
to float--that is they are allowed to vary in altitude.
Floating mode landscapes look like they were clipped out of a
larger area--similar to real world DEM landscapes.

If the Island button is depressed, fractal landscapes will be
generated in Island mode; otherwise they will be generated in
Floating mode.

FrDim
-----
The FrDim value controls the Fractal Dimension (height and
roughness) of the fractal mountains. The value is used for
subsequently generated fractal landscapes. Typing in a new
value does not affect the current landscape unless you
regenerate it. The default value is 100. Larger values will
generate taller, rougher landscapes. Smaller values will
generate flatter, smoother landscapes.

Fractlz
-------
You can fractalize the current landscape to add fractal detail.
If the Fractal Dimension is set to low values the effect is to
smooth the landscape. If the Fractal Dimension setting is high,
the landscape will become rougher. The fractal divisor buttons
1, 2, 4, and 8, immediately below the Fractlz button control
the scale where the fractalizing occurs. At lower values
fractal noise is added only at very small scales--the landscape
will look basically the same shape, just rougher. At higher
values the landscape will start looking rougher, and at larger
scales may no longer resemble the original landscape.

Stretch
-------
The stretch function changes landscapes by vertically
stretching existing features. Peaks will grow taller, valleys
and pits will grow deeper. The scale at which this happens is
controlled by the Fractal Divisor buttons (1, 2, 4, and 8,
immediately above the Stretch button). At lower values only the
smallest features are stretched. At higher values only the
larger features are stretched. You can stretch landscapes over
and over again to create a caricature of the original
landscape.

Fractal Landscape Number
------------------------
This numerical gadget located below the Random button is for
entering the number of the fractal landscape you want to
generate. Alternatively, it displays the random number
generated when you press the Random button. Whether you enter a
number or it is generated randomly, Vistapro uses the number to
generate a fractal landscape. To enter your own value, position
the mouse pointer over the gadget and press the left mouse
button. The pointer will disappear. Type in your number from
the keyboard and press ENTER. Vistapro will then generate that
landscape. Note that the Fractal Dimension and Fractal Divisor
values are used while generating the landscape.

Fractal Divisor
---------------
The Fractal Divisor buttons are the four buttons located
between the Fractlz and Stretch buttons. They are labeled 1, 2,
4, and 8. The values they represent are used by the fractal
generation routines. When Vistapro generates a fractal
landscape (after you press the Random button or enter a value
into the Fractal Landscape Number gadget) it uses the current
divisor setting. The smaller the fractal divisor, the larger
the features of the landscape.

At a setting of 1 very large mountains are generated. At 8,
many small mountains are built. For the Fractalize and Stretch
functions the divisor value represents the frequency at which
the existing landscape data is sampled in order to generate the
new landscape. See the sections for Fractalize and Stretch for
more details.


LIGHT LOWER CONTROL PANEL
-------------------------
Light Source Direction is the direction from which the sun is
shining, and you use it in combination with the exposure,
contrast, and shadow settings to determine the location and
depth of shadows when generating an image. This function
"moves" the sun.

Whenever this panel is selected several concentric circles will
be drawn in black over the landscape. These circles are
reference points so that you can visually estimate the
declination of the sun. The circles are labeled with the
declinations that they represent, 75, 60, 45, 30 and 0 degrees
above the horizon.

A line (the Sun Vector) will be drawn from the center of the
bulls eye out toward the edge of the landscape. The direction
of the line indicates the azimuth (direction around the
horizon) from which the sun is shining. The length of the line
indicates the declination of the light source. You should think
of the Sun Vector as a stick stuck in the center of the
landscape which is pointing at the sun.

Since the topographic map is being viewed from directly
overhead, the longer the stick appears, the closer the sun is
to the horizon. If the stick appears very short it is pointing
nearly straight up.

NSEW
----
Use the North, South, East, and West buttons (labeled N, S, E,
and W) to quickly set one of four "standard" lighting
positions. These buttons are positioned so that you can easily
see from which direction the sun will be shining. When using
one of these positions the sun is at 45 degrees above the
horizon. Using these pre-programmed directions speeds up the
shading phase of rendering when shadows are enabled. After
clicking on one of these buttons you can see the Sun Vector
(the line radiating from the center of the "bulls eye") change
to indicate the new direction.

Custom
------
The Custom button gives you complete control over the direction
and angle of the light source. Selecting this button causes the
Sun Vector to follow the mouse pointer as it moves around the
screen. This represents the position of the sun in the sky.
Think of the line as a stick pointing at the sun from the
center of the landscape. Since you are looking down onto the
landscape from above, the longer the stick is, the closer the
sun is to the horizon; the shorter the stick is, the closer the
sun is to directly overhead. The stick points in the direction
of the sun.

When you have located the desired direction and angle, a single
click with the left mouse button locks this in place. Using a
custom light source may increase the amount of time required to
complete the shading phase of the rendering process when
shadows are enabled.

Exager
------
The Exager (Exaggeration) button enables exaggerated shading.
Imagine a ball in front of you, with a light shining on it from
above. The top of the ball faces the light, and appears very
bright. Points farther down the sides of the ball reflect less
light and appear darker. Halfway down the side, the light no
longer shines on the surface, and it is in shadow. Exaggerated
shading increases the rate at which the shades darken around
the sides of the ball. This technique can add detail to the
image by exaggerating small irregularities on the landscape.
You will probably want to disable this function when setting
the sun at low declinations, since the exaggeration makes all
the flat areas appear very dark.

Azimth
------
Use the Azimuth gadget to set the direction (in degrees from
due south) from which the sun shines. Zero degrees is due
south, 90 degrees, due west, 180 degrees, due north and 270 (or
D90) degrees is due east. Note that this differs from the
heading, which is measured from due north, as is common in
navigation.

Declin
------
Use the Declin gadget to set the declination, the angle from
the horizon from which the sun shines. Zero degrees of
declination puts the sun right on the horizon, while 90 degrees
put the sun directly overhead. This is similar to the way Pitch
is measured for the camera.

Rough
-----
The Rough button sets the apparent roughness of the landscape
when rendered. Vistapro accomplishes this by adding a scaled
random number to the shade of each polygon, so that some of the
polygons will be darker than normal and some will be lighter.
By doing this, large flat areas will appear to have a little
more detail than they otherwise might. To set this value, click
the mouse on the Light button located on the Middle Control
Panel. Click the mouse pointer on the Rough numerical gadget.
Change the number from the keyboard and press ENTER. Useful
values range from 0 to 300, with higher values giving rougher
appearing landscapes. Very large roughness values result in
unnatural shading.

Shadow
------
Vistapro has the ability to render landscapes with shadows.
True shadows are very difficult and time consuming to render so
Vistapro uses a quick, less precise method. Only the landscape
itself casts shadows; trees do not cast shadows. Shadows will
not be cast outside the area of the topographic data. Shadows
are enabled when the Shadow button is depressed. The Shading
phase will require more time when Shadows are enabled.


*** End of Chapter Four ***