QuadTreeGameOfLife

In this directory, you'll find an implementation of Conway's Game of Life (GoL). The simulation is written in C language and uses SDL graphic library.

Table Of Content.

• 1. Project Presentation
• 2. Structure
• 3. Run the Code

1 Project Presentation. [toc]

This project aims to implement the GoL using QuadTree to store cells and the whole universe. The final goal is to compare it to implementations which use arrays (naive implementation), linked-list or others type of structure, at different scale and universe density in terms of computing duration and computing cost. Every implementation must be in C to compare the effectiveness of the structure not the one of the language.

2 Structure. [toc]

The interesting aspect of the project is the way the Conway's Universe is stored. Indeed it uses QuadTree, a classic tree implementation but with 4 children and only not-uniform branches are developed which allow to reduce the needed memory to store the universe while preserving a quick access to a cell ( O(log(n)) ). See an example here:

A Quadtree to store and sort points

The structure of the cells used is :

struct cell{ //origin top left, y increasing down, x incr. right 
    int level;
    int x;
    int y;
    bool alive;
    cell** children; //children is either NULL or a 4 not-NULL-pointers array, can't be [NULL,cell,cell,NULL]
    //format: [top left, tr , bl , br ]
    //coord : [   0 0  , 1 0, 0 1, 1 1]
};

Remarks:

• ONLY cells of level 0 are real Conway's cells
• a cell of level n has a size of 2^n in the universe but needs the same memory space that a lvl 0
• level of the root increases as the universe expands, at any time the size of the universe is 2^root.level
• the alive variable is taken into account only if the cell hasn't any children, then the value of alive is associated to the whole cell and its non-existing children.
• A cell where level != 0 has a size != 1 so can't have real coordinates. So the coord of a level n cell are the coord of its first child (top left).

3 Run the code. [toc]

To run the program you'll need the gcc compiler and the SDL library. You can install both with sudo apt install gcc and sudo apt install libsdl2-dev on Ubuntu 20.04 LTS. Then, run make app in the root folder of the project. NB: to re-run the program just type ./out/app, files are already compiled. To clean the repository you can run make clean.