Line of sight

gistfile1.cpp

for (int x0 = playerXPos-MAPSIZE*2; x0 <= playerXPos+MAPSIZE*2; x0++){
  	for (int y0 = playerYPos-MAPSIZE*2; y0 <= playerYPos+MAPSIZE*2; y0++){
			int dx = abs(x0 - playerXPos);
			int dy = abs(y0 - playerYPos);
			int x = playerXPos;
			int y = playerYPos;
			int n = 1 + dx + dy;
			int x_inc = (x0 > playerXPos) ? 1 : -1;
			int y_inc = (y0 > playerYPos) ? 1 : -1;
			int error = dx - dy;

			dx *= 2;
			dy *= 2;

			for (; n > 0; n--){
				if (error > 0){
					x += x_inc;
					error -= dy;
					if (tiles[y][x].wallsGFX ==0){
						tiles[x][y].rays = 1;
					}
					else if (tiles[y][x].wallsGFX !=0){
						break;
					}
				}

				else{
					y += y_inc;
					error += dx;
					if (tiles[y][x].wallsGFX ==0){
						tiles[x][y].rays = 1;
					}
					else if (tiles[y][x].wallsGFX !=0)
						break;
				}
			}
		}
	}