1. Renato Cunha
  2. tgalaxy

Overview

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About
^^^^^
This is an implementation of Renato Cunha's own interpretation of
the Space Invaders game/atmosphere.

Build Instructions
^^^^^ ^^^^^^^^^^^^
For installation instructions, please refer to the INSTALL file. If you don't
want to read that file, here are the basic instructions:

On an UNIX-like system, the canonic form will work:
 * ./configure
 * make
The game will be located in the src directory. If you want to install it, just
call:
 * make install

Please notice that you'll need OpenGL + glut development packages and, on
non-MacOSX systems, the X11 development packages.

On Windows:
 Assuming that you have installed mingw and msys on the default directories,
issuing
 * make -f Makefile.win
from msys's prompt should work.

Gameplay notes
^^^^^^^^ ^^^^^
As you might know already, your objective in this game is to destroy the nasty
aliens that are trying to invade Earth. You are Earth's last hope against the
alien hordes. To accomplish your mission, you must control your space-adapted
airplane. The game controls are mouse-based. Move your mouse towards the
window right border and your ship will move right. Move it to the left border,
and it will move left. If you don't want it to move at all, leave your mouse
in the window's center. To shoot, just left click your mouse.

Additional controls
^^^^^^^^^^ ^^^^^^^^
* Right click or 'p' key - (un)pause game
* Middle click or 'd' key - Enters debug mode (pauses the game and prints the
  game objects' parameters to a console
* Pressing the 'r' key restarts the game

Implementation notes
^^^^^^^^^^^^^^ ^^^^^
While implementing this game I decided to do an exercise on modularization in
an object-oriented way. So each game object is implemented in its own class
that derives from the GameObj base class. There is also a world class,
responsible for managing the game objects.

To try to keep the class coupling to a minimum, an entity manager (that stores
all game objects) was implemented, along with a message-passing system (so
that game objects communicate via message passing, instead of calling each
others methods) comprised of a message dispatcher and a basic message class,
called Telegram. The basics of the this "technique"(?) can be found on the
book "Programming Game AI by Example", by Mat Buckland. The Game class is
responsible for handling input, FPS-limiting, and drawing the interface only
(each object is responsible for drawing itself).

Originally, I tried to keep the design as clean as possible. Unfortunately, I
eventually forgot to examine some class interaction properties, and that made
me add some inconsistencies to the class hierarchy. Well, that's the way life
is.

Some macro implementation ideas, like DebugPrint, were taken from stratagus,
an open source RTS engine.