Game Development Reference
In-Depth Information
If shown horizontally, zero is at the left and the maximum at the right; if shown
vertically, zero is at the bottom and maximum is at the top. The chief benefit of
power bars is that the player can read the approximate level of the value at a glance.
Unlike a thermometer, they rarely carry gradations. You can superimpose a second
semitransparent bar of a different color on top of the first one if you need to show
two numbers in the same space. Many power bars are drawn in green when full and
change color to yellow and red as the value indicated reaches critically low levels to
help warn the player. Power bars are moderately space efficient and, being themati-
cally neutral, appear in all sorts of contexts. You can make themed power bars; a
medieval fantasy game might measure time with a graduated candle or an hourglass.
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Small multiples.
Small-integer numeric. (On a mobile phone, the bars indicat-
ing signal strength.) A small picture, repeated multiple times, can indicate the
number of something available or remaining. Small multiples are traditionally used
to represent lives remaining in action games; often they appear as an image or sil-
houette of the avatar. Nowadays designers use them for things the avatar can carry,
such as grenades or healing potions, although you should limit the maximum
number to about five; beyond that the player can't take in the number of objects at
a glance and must stop to count the pictures. To make this method thematically
appropriate for your game, simply choose an appropriate small picture.
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Colored lights.
Symbolic. (In a car, various lights on the instrument panel.)
Lights are highly space efficient, taking up just a few pixels, but they can't display
much data; normally they indicate binary (on/off) values with two colors, or tri-
state values with three (off/low/high). Above three values, players tend to forget
what the individual colors mean, and bright colors are not thematically appropriate
in some contexts. Use a suitable palette of colors.
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Icons.
Symbolic. (In a car, the symbols indicating the heating and air condition-
ing status.) Icons convey information in a small space, but you must make them
obvious and unambiguous. Don't use them for numerical quantities but for sym-
bolic data that record a small number of possible options. For example, you can
indicate the current season with a snowflake, a flower, the sun, and a dried leaf.
This will be clear to people living in the temperate parts of the world where these
symbols are well known, but it will work less well in cultures where snow doesn't
fall. The player can quickly identify icons once she learns what they mean, and you
can help her learn by using a
tooltip
, a small balloon of text that appears momen-
tarily when the mouse pointer touches an icon for a few seconds without clicking
it. Don't use icons if you need large numbers of them (players forget what they
mean) or if they refer to abstract ideas not easily represented by pictures. In those
cases, use them with text alongside, or use text instead. Make your icons themati-
cally appropriate by drawing pictures that look as if they belong in your game
world. The icons in
Cleopatra: Queen of the Nile
, set in ancient Egypt, are excellent
(see Figure 4.8).
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Text indicators.
Symbolic. Text represents abstract ideas well, an advantage over
other kinds of indicators. In
Civilization III
, for example, an advisor character can
