Arduino Uno Quick Start Manual page 176

if (z_button) {
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init_game();
20
state = RUNNING;
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}
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}
-
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void game_over() {
25
tv.clear_screen();
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tv.select_font(font8x8);
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tv.printPGM(28, 38,
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int x = (WIDTH - 7 * 8) / 2;
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if (hits > 9)
30
x = (WIDTH - 8 * 8) / 2;
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tv.printPGM(x, 50,
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tv.print(x + 6 * 8, 50, hits);
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if (z_button) {
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state = STARTING;
35
z_button = false;
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delay(200);
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}
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}
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40
void update_game() {
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tv.clear_screen();
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tv.draw_circle(target_x, target_y, target_r, WHITE);
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move_crosshairs();
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draw_crosshairs();
45
check_target();
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if (target_count == MAX_TARGET + 1) {
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state = DONE;
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z_button = false;
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delay(200);
50
}
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}
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The intro , start_game , and
message to the screen, then they wait for a Z button press. If the Z button
was pressed, they move to the next state. Before they move to the next state,
they set z_button to false and wait for 200 milliseconds. This is necessary to
debounce the Z button.
All three functions use yet another TVout method. Look at line 3, for example.
Here we use TVout s
but it reads the string to be output from the Arduino s flash memory and not
from its precious SRAM. For applications that display a lot of constant mes-
sages, this can save a lot of memory.
PSTR("Game Over"));
PSTR("Hits: "));
game_over functions are very similar. They print a
method. It works like the regular
printPGM
www.it-ebooks.info
Creating Your Own Video Game
method,
print
159
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