Raycayst

#include <SFML/Graphics.hpp>
#include <cmath>


#define DEFAULT    sf::Style::Default
#define FULLSCREEN sf:Style::Fullscreen

#define WIDTH  24
#define HEIGHT 24

int worldMap[WIDTH][HEIGHT]={
  {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,2,2,2,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
  {1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,3,0,0,0,3,0,0,0,1},
  {1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,2,2,0,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,0,0,0,0,5,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,0,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
  {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
};

int main(void){

    sf::RenderWindow window(sf::VideoMode(800, 600), "Raycast test", DEFAULT);
    window.setFramerateLimit(30);

    double posX = 22, posY = 12;
    double dirX = -1, dirY = 0;
    double planeX = 0, planeY = 0.66;

    double time = 0;
    double oldTime = 0;


    while(window.isOpen()){
        for(int x = 0; x < 800; x++){
            double cameraX = 2 * x / (double)800 - 1;
            double rayPosX = posX;
            double rayPosY = posY;
            double rayDirX = dirX + planeX * cameraX;
            double rayDirY = dirY + planeY * cameraX;

            int mapX = (int)rayPosX;
            int mapY = (int)rayPosY;

            double sideDistX;
            double sideDistY;

            double deltaDistX = sqrt(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX));
            double deltaDistY = sqrt(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY));
            double perpWallDist;

            int stepX;
            int stepY;

            int hit = 0;
            int side;

            if(rayDirX < 0){
                stepX = -1;
                sideDistX = (rayPosX - mapX) * deltaDistX;
            }else{
                stepX = 1;
                sideDistX = (mapX + 1.0 - rayPosX) * deltaDistX;
            }
            if(rayDirY < 0){
                stepY = -1;
                sideDistY = (rayPosY - mapY) * deltaDistY;
            }else{
                stepY = 1;
                sideDistY = (mapY + 1.0 - rayPosY) * deltaDistY;
            }

            while(hit == 0){
                if(sideDistX < sideDistY){
                    sideDistX += deltaDistX;
                    mapX += stepX;
                    side = 0;
                }else{
                    sideDistY += deltaDistY;
                    mapY += stepY;
                    side = 1;
                }

                if (worldMap[mapX][mapY] > 0){
                    hit = 1;
                }
            }

            if(side == 0){
                perpWallDist = (mapX - rayPosX + (1 - stepX) / 2) /rayDirX;
            }else{
                perpWallDist = (mapY - rayPosY + (1 - stepY) / 2) /rayDirY;
            }

            int lineHeight = (int)(800 / perpWallDist);

            int drawStart = -lineHeight / 2 + 800 / 2;
            if(drawStart < 0){
                drawStart = 0;
            }
            int drawEnd = lineHeight / 2 + 800 / 2;
            if(drawEnd >= 800){
                drawEnd = 800 - 1;
            }

            sf::Color color;
            switch(worldMap[mapX][mapY]){
            case 1: color = sf::Color::Red; break;
            case 2: color = sf::Color::Green; break;
            case 3: color = sf::Color::Blue; break;
            case 4: color = sf::Color::White; break;
            default: color = sf::Color::Yellow; break;
            }

            sf::Vertex line[2] ={
                sf::Vertex(sf::Vector2f(x, drawStart), color),
                sf::Vertex(sf::Vector2f(x, drawEnd), color)
            };

            window.draw(line, 2, sf::Lines);
            window.display();
        }

        sf::Event event;
        while(window.pollEvent(event)){
            if(sf::Keyboard::isKeyPressed(sf::Keyboard::Escape)){
                window.close();
            }
        }
    }
    return 0;
}