Be Quick or be Dead by Nick Shcherbyna

   (c) 2021 Nick Shcherbyna (Lviv, Ukraine)   computer.history.lviv@gmail.com

=< INSTRUCTIONS >=========================================================

Pretty standard situation for Wild West - two cowboys with guns are starting the duel. Shoot first or die, be quick or be dead!
After signal a message "Press [?] to shoot" appears on the screen, with a random
lowercase letter shown. Strike the corresponding key immediately, otherwise your
opponent will shoot first and kill you. After shooting press [SPACE] to initiate
another duel.

=< SOURCE CODE EXPLAINED >======================================================

0 Disable sleeping. Clear screen. Display game title and copyright. Wait for any
  key or timeout.
1 Clear screen. Draw left and right (mirrored) cowboys.
2 Draw ground (3D projection). Pick random letter and show message after signal.
  Pick random timeout.
3 Wait for valid keypress or timeout. Determine who pulled a trigger first. Draw
  the gun.
4 Get shooting direction. Play sound. Animate the bullet.
5 Wipe the standing cowboy and draw a dead one simultaneously.
6 Print win/dead message. Animate the smoking gun until spacebar is pressed.
7 Cowboy image scanlines. Two values specify start and end coordinates. Negative
  start prevents incrementing the scanline (absolute value is used). Zero end is
  a stop mark.
8 Cowboy image scanlines, continued.
9 Cowboy image scanlines, continued. Signal frequency. Gun component widths.

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