About Warp
How to play
This part is so simple it doesn't really warrant any
explanation. Shoot at everything that moves and some of the things that
don't. You'll soon learn which objects can be blown up and which ones just
absorb the blasts. Avoid flying into anything that looks bulky and sticks
out of the ground.
Keep in mind that most Java-enabled browsers
require that the cursor is located within the current applet area for the
keyboard input to be directed to the applet. Some may even insist on an
initial mouse click.
How to cheat
I didn't spend weeks preparing the graphics of Warp
just to have them gather dust because most people are too lousy players
to get any further than level one. You can start any of the first five
levels by pressing the
SHIFT key plus A, B, C,
D or E.
Platform-specific problems
On certain machines with slow graphics cards but fast
processors, the "curtain" effect between levels and when losing a life
will not look right. It will appear to take only two or three steps before
the screen goes blank. This is because the main loop has a period of no
less than 70 milliseconds and the computer can't redraw the screen that
often, so it will simply ignore the update request and wait for the next
one ... or the next after that. However, during actual play, the loop has
a lot more to do and will usually be delayed for so many extra milliseconds
that the computer does have time to carry out the updates.
Technical stuff
Although each level is more than ten screens long
(and can be made any size) the graphics area that stores the background
is in fact just a little over two screens. Think of the current view as
a window that moves upward along the graphics area. New ground is continuously
being drawn above the window. At the same time an exact replica is drawn
below it, so that when the window reaches the top of the graphics
area it can jump down to the bottom and continue seamlessly from there.
The cost of this on-the-fly graphics updating is (at most) one Graphics.drawImage
operation per animation cycle and it saves a tremendous amount of memory.
Another memory-saving strategy I've used
in Warp is to load the graphics of each new level separately and
throw them away when they are no longer needed. This dramatically cuts
down on the number of Image objects the applet needs to allocate and of
course reduces the download time for netsurfers who weren't going to play
all nine levels anyway. (I was actually
forced to do this because
the game would have been too big to run on my humble Macintosh Performa
6200 otherwise.)
To make the scrolling as smooth as possible,
I don't update the score display and the blasted stationary objects immediately,
but wait until the graphics updating has a spare cycle. I'm not sure exactly
how much effect this has, but on slow machines I suppose every little bit
helps.
Ingredients
Warp needs ten graphics files - one for each level
and one that holds the parts that make up the control panel and the things
that remain constant at each level, like explosions. They are named warp0.gif
through
warp9.gif and can be found in the current directory. The game also
needs sounds. KA-PEOOO!, CRASH! and BING! come in
individual audio files named warpsnd0.au, etc.
Source code
This is what the code looks
like.
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