float posX = 9, posY = 12.5;
    float dirX = -1, dirY = 0;
    float planeX = 0, planeY = 0.9;
    float time = 0, oldTime = 0;

    float cameraX, rayPosX, rayPosY, rayDirX, rayDirY, sideDistX, sideDistY, deltaDistX, deltaDistY, perpWallDist, frameTime, moveSpeed, rotSpeed, oldDirX, oldPlaneX;
    int x, y, mapX, mapY, stepX, stepY, hit, side, lineHeight, drawStart, drawEnd;

                cameraX = 2 * x / (float)(screenWidth) -1;
            rayPosX = posX;
            rayPosY = posY;
            rayDirX = dirX + planeX * cameraX;
            rayDirY = dirY + planeY * cameraX;

            mapX = (int)(rayPosX);
            mapY = (int)(rayPosY);
            deltaDistX = SquareRootFloat(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX));
            deltaDistY = SquareRootFloat(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY));
            hit = 0;

            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;
            }