Game of Life (Raylib)

/******************************************************************************
*
*   Game of Life by Skaruts (raylib 2.5)
*
*   Press
*       Enter to randomize the cells
*       Space to pause/unpause
*       G to pass one generation (if paused)
*       F1 to turn on/off the FPS counter
*       Q to quit (I'm just used to having this while testing)
*
******************************************************************************/
#include "raylib.h"



// quick way to modify the size of the cells, grid and window in the same proportion
// use values 1, 2, 4, 8 or 16 (higher means less performance)
#define m 4

#define CS 16/m     // cell size
#define GW 80*m     // grid width
#define GH 50*m     // grid height

Color dead_cell = DARKGRAY;
Color alive_cell = ORANGE;

bool draw_fps = true;
bool draw_dead_cells = false; // taxing on perfomance
bool paused = false;

int prev_buf = 0;    // to alternate between cell buffers
int curr_buf = 1;

int pad;    // add a padding space around cells (just to look nicer)
int pad2;

int cells[2][GH][GW];



void randomize_cells() {
    for(int buf = 0; buf < 2; buf++) {
        for(int j = 0; j < GH; j++) {
            for(int i = 0; i < GW; i++) {
                cells[buf][j][i] = GetRandomValue(0, 1);
            }
        }
    }
}

void init_cells() {
    pad = 1;        // top and left padding
    pad2 = pad*2;   // bottom and right padding

    if (m > 4) {    // check if cells aren't too small, or else they become invisible with padding
        pad = 0;    // the condition should be adjusted if default padding values are changed
        pad2 = 0;
    }

    randomize_cells();
}

void pass_generation() {
    prev_buf = 1 - prev_buf;      // switch buffers
    curr_buf = 1 - curr_buf;

    for (int j = 0; j < GH; j++) {
        for (int i = 0; i < GW; i++) {

            // wrap around
            int j_ = j-1 >=  0   ?   j-1   :  GH-1;
            int _j = j+1 <  GH   ?   j+1   :     0;
            int i_ = i-1 >=  0   ?   i-1   :  GW-1;
            int _i = i+1 <  GW   ?   i+1   :     0;

            // count alive neighbors
            int n =   cells[prev_buf][ j_    ][ i_    ]
                    + cells[prev_buf][ j_    ][   i   ]
                    + cells[prev_buf][ j_    ][    _i ]
                    + cells[prev_buf][   j   ][ i_    ]
                    + cells[prev_buf][   j   ][    _i ]
                    + cells[prev_buf][    _j ][ i_    ]
                    + cells[prev_buf][    _j ][   i   ]
                    + cells[prev_buf][    _j ][    _i ];

            // set cell according to rules
            cells[curr_buf][j][i] = (int) n == 3 || ( cells[prev_buf][j][i] && n == 2);
        }
    }
}

int main() {
    // set window size according to grid and cell sizes
    // (makes a 1280x800 window if only the value of 'm' is tinkered with)
    int screenWidth = GW*CS;
    int screenHeight = GH*CS;

    InitWindow(screenWidth, screenHeight, "Game of Life (by Skaruts) - raylib test");
    SetTargetFPS(60);
    bool running = true;

    init_cells();

    while (running) {
        if (WindowShouldClose() || IsKeyPressed(KEY_Q)) running = false;
        if (IsKeyPressed(KEY_SPACE))                    paused = !paused;
        if (IsKeyPressed(KEY_ENTER))                    randomize_cells();
        if (IsKeyPressed(KEY_F1))                       draw_fps = !draw_fps;

        if (paused) {
            if (IsKeyPressed(KEY_G))
                pass_generation();
        }
        else {
            pass_generation();
        }

        BeginDrawing();
            ClearBackground(BLACK);

            for(int j = 0; j < GH; j++) {
                for(int i = 0; i < GW; i++) {
                    int x = i*CS+pad;
                    int y = j*CS+pad;
                    int w = CS-pad2;
                    int h = CS-pad2;

                    if (cells[curr_buf][j][i])
                        DrawRectangle(x, y, w, h, alive_cell);
                    else if (draw_dead_cells)
                        DrawRectangle(x, y, w, h, dead_cell);
                }
            }

            if (draw_fps) {
                DrawFPS(10, 10);
            }

        EndDrawing();
    }

    CloseWindow();
    return 0;
}