From: phillips@swanee.ee.uwa.oz.au (Christopher Phillips)
Subject: Re: player energies; applicable to shootemups?
Organization: Elec Eng, Univ of Western Australia
Date: 11 Oct 92 10:13:31 GMT

cnc@balboa.eng.uci.edu (Christopher Christensen) writes:

>Excellent point!  I can easily extend the energy/body idea to model
>this behavior..
>3 stats:  usable energy, stored energy, and body.

and goes on to espouse an excellent system of long & short term fatigue
etc.

A subject I would like to discuss is that of energy systems in arcade
like games.  Ideas like Christophers could add interesting elements
of strategy to blastemups; people could try to conserve energy for encounters
with massive end of level beasties etc.

I have come across many systems in various games over the years, most
of which keep 'health' and 'weapon availability' fairly separate (other
than be reduceing you weponary by some extent whenever you die).  Because
of this, I will discuss the two separately in the following summary
of nice systems i have come across.

_Weapon energy systems_

My favourite is the one used by Armalyte, the best c64 shootemp of 1987
(perhaps all time?).
In addition to your standard bullet weapons, you have a choice of three
super-weapons, each of which requires a different number of units of energy
per shot, and different levels of spread, fire rate etc.  Your
ship starts off with one storage battery, capable of storing 6 units of charge.
At various places in the levels can be found weapon crystals.  These
could be shot to convert them into additional 'standard fire' in various 
directions, or into batteries for increased charge storage, or into additional
generators to allow you batteries to recharge faster.  There was a limit
of 4 additional batteries, and about 5x speedup of your recharge rate.

Then there is the sort used by R-Type and various clones.  You have
one weapon which accumulates charge while the fire button is depressed,
indicated by a charge level displayed in the status area. When the
fire button is released, all the charge is released in a single bolt.  
Hence, you could fire many small bolts by firing repeatedly, or at the expence
of not firing at all for a short period of time, you could release a massive 
energy bolt, with any level between accesable by timing.

Turrican I&II both allow you to release unlimited lightening/rapid fire
if you pause while on solid ground for a second without firing in preparation.
Like R-Type, again we have the concept of a major bolt requireing you to
sacrifice some capabilities for a short time beforehand.

_Lives systems_

Two boring variants:  
Lose all your lives and the game ends.  A life is lost on any damage.
Lose all your energy and the game ends.  Damage causes energy loss.

The second of the above two is just a finer grained variant of the
first.  They are often used in conjunction.

More interesting:
Turrican uses a three tiered system.  You have energy (decreases with
damage), loss of all of which loses you a life.  If you lose
a life, your weponry decreases slightly, but you continue from the
last safe place you stood.  (a major problem with Turrican is that
the side of a bottomless chasm (no place to go but down to your death)
is considered a 'safe place to stand'; hence you lose all your lives if
you catch against the side on your way down).
Once all your lives are lost, you may use a 'continue' to restart from
the beginning of that level.  You begin the game with three continues,
but more can be earned by collecting crystals (300/continue)  Extra lives
and energy restorers may also be found.

I think it would be interesting to try to combine a small number of
stats into a realistic damage/weaponry availability system.  Facilities
like additional craft speed could also be incorporated into the system.

Any comments, intersting ideas?  I will throw some around later.

Enjoy!

Christopher. (Jam(es phillips))

ps. Apologies for typos etc in the above; I am working over a slow link and 
cannot be bothered fixing them all.
--
Christopher Jam	__________________________________________________
phillips@swanee.ee.uwa.edu.au			c64 forever!!!!
300,000 c64's were sold in the fiscal year ending June 1991 :)
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