Arduino Uno Quick Start Manual page 173

unsigned long target_creation;
10
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enum GameState {
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INTRO, STARTING, RUNNING, DONE
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};
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15
GameState state;
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In game programming you often have to manage a lot of global variables—even
in a small game like ours. First, we define a TVout instance named
Nunchuk instance named
all Nunchuk properties we re interested in. They all work the same—we set
up to true , for example, if the user pushes the Nunchuk s analog stick upward.
chx and chy contain the current position of the crosshairs.
its X and Y velocity. Similarly,
current target. Because the target is a circle, we also need a radius, which
we store in target_r .
target_count contains the number of targets we ve created already, and in
you can find the number of targets the player has hit so far. Targets disappear
automatically after a short period of time, so we need a place to store the
creation time of the current target. This place is
In line 12, we define an enumeration that lists our game s potential states. If
the game is in the
player to press the Z button. If the player presses the Z button, the game
changes to the
STARTING
another button press to give the player some time to prepare.
The RUNNING state is where all the action is. In this state the game loop creates
new targets, checks the player s moves, and so on. After all targets have
appeared, the game state changes to
screen and the number of targets that he or she has hit.
We need to initialize all of these global variables whenever a new game starts.
The following functions will do that:
Tinkering/Pragduino/Pragduino.ino
void init_game() {
up = down = left = right = c_button = z_button = false;
chx = WIDTH / 2;
chy = HEIGHT / 2;
chvx = 1;
chvy = 1;
state = INTRO;
target_count = 0;
nunchuk . After that, we define Boolean variables for
and
target_x
INTRO state, it displays a title screen and waits for the
state. It outputs a "READY?" message and waits for
DONE
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Chapter 9. Tinkering with the Wii Nunchuk
chvx and
contain the position of the
target_y
target_creation .
. The player will see a game-over
156
and a
tv
chvy contain
hits
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