if(wall_front && depth < DRAW_DEPTH){
// 上
SDL_DrawLine(screen,
(int)(X_CENTER - (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER - (Y_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(X_CENTER + (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER - (Y_HALF / (1 + Z_BLOCK * (depth+1)))),255, 255, 255);
// 下
SDL_DrawLine(screen,
(int)(X_CENTER - (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER + (Y_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(X_CENTER + (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER + (Y_HALF / (1 + Z_BLOCK * (depth+1)))),255, 255, 255);
if(wall_left){
SDL_DrawLine(screen,
(int)(X_CENTER - (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER - (Y_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(X_CENTER - (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER + (Y_HALF / (1 + Z_BLOCK * (depth+1)))),255, 255, 255);
}
if(wall_right){
SDL_DrawLine(screen,
(int)(X_CENTER + (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER - (Y_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(X_CENTER + (X_HALF / (1 + Z_BLOCK * (depth+1)))),
(int)(Y_CENTER + (Y_HALF / (1 + Z_BLOCK * (depth+1)))),255, 255, 255);
}}}