# A computer game

[Developement Blog](https://alistairmichael.com/projects/game/)

![image](https://alistairmichael.com/media/game3.png)

This is a simple game where you play as a bouncy square rock that has a grappling hook. It can use the grappling hook to swing to the end of the cave. There is no reward for doing so, but there is a timer. 

### Description and Features

- Entirely written in C using only the SDL2 graphics and audio libraries. 
- Procedurally generated cave environment using a random walk and procedurally 
  generated colour palettes.
- Cute synthesized sound effects using integer overflow a la [bytebeat](https://arxiv.org/pdf/1112.1368.pdf).
- 2D Graphics using the SDL2 API, no assets are used aside from the font.
- Point mass elastic physics with elastic collisions.
    - Separating Axis Theorem collision test for convex polygons. 
    - Framerate independent physics uses a fixed timestep and completes as many 
      steps as neccessary to catch up to each frame.  
    - Physics runs in a separate thread and state is managed using shared memory and 
      locks. 
    - Player physics interactions use forces applied to physics bodies which are 
      integrated into impulses and positions. 
- Grappling hook.

# Installation

## Prebuilt Binary

See the releases tab.

On Linux and other Unix-Like operating systems you will need to install the SDL2 
package from your package maintainer. 

```sh
# on Fedora
sudo dnf install SDL2
```

# Build Instructions

## On Linux / Unix

Install the [libSDL2](http://libsdl.org/download-2.0.php) runtime and SDL2 
development packages from your package distributor.  On Fedora, this 
is the `SDL2` and `SDL2-devel` packages.

```sh
git clone --recurse-submodules https://git.topost.net/alistair/space_game.git
```

(if you forget `--recurse-submodules` you can use, `git submodule init`, `git submodule update`.)

### For Linux

```sh
make clean
make target=linux
```

### For Windows

You have to have mingw and the mingw libsdl library (I think).

```sh
sudo dnf install mingw64-SDL2 mingw64-SDL2_image mingw64-SDL2_ttf mingw64-winpthreads mingw64-winpthreads-static
```

Run setup.sh to download the SDL2 static libraries and `SDL2.dll`.

```
./setup.sh
make clean
make target=windows
```

## FreeBSD

You need to download the header files and put them in the source folder, with
the folder name SDL2. You also need the `sdl2` and `gmake` packages.

Something like this:

```sh
cd /tmp && wget https://www.libsdl.org/release/SDL2-2.0.12.zip && unzip SDL2-2.0.12.zip
mv /tmp/SDL2-2.0.12/include $source_dir/SDL2
pkg install sdl2 gmake
cd $source_dir
gmake
```

### With debug flags

Append `debug=true` to the make command.