Compiling:

# Install sox (avaible in all major linux distros)
pacman -S sox

# Clone the repo
git clone https://github.com/MatMercer/ncurses-space-invaders.git
cd ncurses-space-invaders

# Generate the build files and compile
cmake .
make
# Play the game
./bin/spaceinvaders
./bin/spacedebug # Debug version

About the project

Space Invaders is a game proposed as a college assignment for the teacher Augusto Luengo Pereira Nunes at the Federal Institute of Paraná Londrina. The game is inspired by The Original Space Invaders containing all the same elements, less barriers.

Code structure

Boot Functions

Functions that begin with the name "init" are used to initialize the components of the game, for example the initAliens() function allocates the aliens and places them in the correct starting position. The startup main function is the initGame(), which the ncurses starts.

Main Game Loop

All functions are called within a loop ta the main loop in the function startSpaceInvaders() and are divided into two categories:

• Game logic functions.
• Rendering Functions.

The render() function renders all the components of the game. Logic Functions are called after render() within the startSpaceInvaders() function, this causes independence between the rendering and physics of the game. The game works even though one or all of the components are not rendered.

Main Elements

Borders / Scenery

The default character of the border is *. The edges are drawn centrally, based on the window size (terminal) when running the game. If the window is smaller than the minimum size set (90 characters wide and 45 characters wide height characters), the borders will be drawn according to the mininum size.

The default border is yellow, in case the player loses a life the edge becomes red and the character * is replaced by X. In case of victory, the border becomes green and the character * is replaced by +. All characters in the game are printed bold on the screen and each component has a different color.

Aliens

The aliens move together and uniformly, automatically, after a certain interval of time. This interval is based on a variable. The movements start to the right and change the horizontal direction after each collision with the lateral edges. In addition, the aliens descend a vertical position after collisions.

Each alien has a boolean type variable that informs its state of life. The aliens have three lasers, which are generated randomly with the same movement interval of the aliens. Only the last alien in each column can shoot.

Player Spaceship

The starting position of the player is centered just above the bottom edge. The player's ship is moved by the keyboard arrows, which control the the player.

The laser in the player is activated with the space key and can can only be shoot one at a time. The shooting ends with the hit of an alien or a hit from the top edge.

Sound

There are various sound effects in the game, which improve considerably the user experience and even the gameplay. The 'M' key is used to turn the game sounds on or off. The sounds are played with the playSound() function. By default their format is a .wav and the command to play has the following format:

play -q {executable path} / sfx / {file name} {extension} &

The getWorkingDirectory() function is crucial for this command to work because it finds the path of the executable. The final part of this & command causes it to run on a differente proccess, preventing the game from pausing when a sound is touched. The play command is available in different linux distributions by the sox package. So the command to install this package on debian based distributions is simple:

$ apt-get install sox

The sounds were generated by Gabriel Ranea from the website [SuperFlashBros] (http://www.superflashbros.net/as3sfxr/).

Score

The score is incremented by 10 points for each alien eliminated. The player can score is in the upper right corner of the game and the final screen of "Game over".

Collisions

The collisions are detected from the X and Y positions of the items (aliens vs. lasers) (player vs. lasers). For example, all aliens check if a player's laser touched it, in case it occurs, it is no longer rendered and does not move anymore.

Lives

The player starts with 3 lives, which are shown in the upper left corner of the screen. Every time the player suffers damage from a laser his life is decremented by 1.

Game over

The game can be closed in two ways, with the player winning or losing. In both cases, an animated "Game Over" message is shown in the screen, informing the score of the player and whether or not he won the game. The player may choose to quit the game or restart.

Victory

The player only wins if all aliens are eliminated. Verification is done based on the player's score compared to the amount of aliens multiplied by the score of each slaughtered alien. Ex: 25 aliens x 10 points = 250 points to win the game.

Defeat

The player is defeated if:

• The player has no more lives.
• Any alien touch the bottom edge.
• Any alien touch the player.

Conclusion

The development of this game was very important to our experience. because we had contact with technologies that we did not have prior knowledge. Such as Makefile, CMake, Clion and Doxygen. In addition, due to the fact that this program was made for Linux OS, we gained a deeper understanding of the on how this system works.