Space Invaders 1978 - SDL2

Inspiration

Original Space Invaders from 1978:

• emulated with original ROM files: https://blog.loadzero.com/blog/si78c/ / https://github.com/loadzero/si78c
• original Z80 source code with comments: https://computerarcheology.com/Arcade/SpaceInvaders/Code.html
• another emulation with ROM files: https://github.com/superzazu/invaders

Screenshots where taken from the amazing Javascript "video" player embedded in loadzero's website.

Graphical assets were drawn manually with GIMP, Pinta and Drawing, neither of them being a good tool to edit such tiny bitmaps.

Getting started

Install tools & dependencies

With Ubuntu 22.04 / 20.04 (should work with other Debian derivatives, too):

sudo apt install git build-essential cmake libsdl2-dev libsdl2-image-dev

Initialize the local repository

cd <source-root>
git clone <project>
git submodule init
git submodule update

NB: thanks to https://gitlab.com/aminosbh/sdl2-cmake-modules for the SDL2 cmake integration!

Build the game

cd <project-root>
mkdir build
cd build
cmake ..
make

Launching game from build directory

ln -s ../assets assets
./space-invaders

Scenes

• [BOOT] startup, displays random chars for 1+ second
• [HOME] menu with score for each invader
• [PLAY] intro for player 1 or 2
• [GAME] game itself for player 1 or 2
• [OVER] player(s) loose (TODO)
• [NEXT] next level for player 1 or 2 (TODO)

Keys

Key	Description
[1]	start 1 player game
[2]	start 2 players game (TODO)
[left arrow]	move ship left
[right arrow]	move ship right
[space]	fire
[escape]	quit
[c]	insert coin / add credit
[r]	reboot (restart to boot scene)
[+ (numpad)]	increase speed
[- (numpad)]	decrease speed
[g]	toogle grid
[d]	toogle debug
[s]	toogle screenshots
[enter (numpad)]	change screenshot

TODO

UX/UI

• 4/3 landscape screen with borders instead of original 8/7 portrait aspect ratio
• hide/show debug
• hide/show screenshots

Game

• player move [GAME]
• player fire [GAME]
• aliens move [GAME]
• aliens kills [GAME]
• alien bombs [GAME]
• player kill by bombs [GAME]
• alien victory [GAME]
• player victory [GAME]
• shield demolition (by player & aliens) [GAME]
• saucer management (frequency & score) [GAME]
• sounds (background, fire, bombs (?), kills/explosions, saucer, ...) [GAME]
• next level after victory [NEXT]
• 2 player game
• horizontal color stripes (adhesive tape style)
• high score load / save
• flash 0000 score for 1+ seconds on [PLAY] scene
• animations from original game on home screen [HOME]

Ideas

• function keys instead of 1, 2 and others?
• level counter?
• pause game?
• credits (scene or pop-up with semi-graphic chars)?
• backgrounds/borders around 4/3 screen?
• buttons + mouse for commands / settings (within borders)?
• fullscreen mode?
• DEB/RPM packages (with OpenSUSE build service)?

EOF