Allegro C++库

Question

我一直有这个问题一段时间。当我编译我的代码的这部分时，它显示位图上方的黑线。什么可能是问题，有没有解决办法？

void start() 
{ 
    FONT *verdana; 
    PALETTE palette; 
    verdana = load_font("verdana.pcx", palette, NULL); 
    clear_to_color(screen,makecol(0,0,0)); 
    SAMPLE *tac = load_sample("clunk.wav"); 

    topce_bmp=load_bitmap("topce.bmp",NULL); 
    palki_bmp=load_bitmap("palka.bmp",NULL); 

    int cred_anim=255; 
    int cred_anim_fade=0; 
    SPEED=4; 
    int timer=0;  
    while(cred_anim_fade!=255) 
    { 
     line(screen, 3, 0, 3, 600, makecol(cred_anim_fade, cred_anim_fade, cred_anim_fade)); 
     line(screen, 797, 0, 797, 600, makecol(cred_anim_fade, cred_anim_fade, cred_anim_fade)); 
     if(key[KEY_ENTER]) 
     { 
       menu(0,NULL); 
     } 

//  BATS 


     if(y>0&&y<400) 
     { 
      y=posy-100; 
     } 
     else if(y<=0) y=1; 
     else if(y>=400) y=399; 

     draw_sprite(screen,palki_bmp, 20, y); 

     if(y1>0&&y1<400) 
     { 
      y1=posy-100; 
     } 
     else if(y1<=0) y1=1; 
     else if(y1>=400) y1=399; 

     draw_sprite(screen,palki_bmp, 765, y1); 
     rest(10); 
     cred_anim_fade++; 
    } 

    while (timer!=1000) 
    { 

     if(key[KEY_ENTER]) 
     { 
       menu(0,NULL); 
     } 

     timer++; 
     acquire_screen(); 

     clear_to_color(screen,makecol(0,0,0)); 


//  BORDERS 

     line(screen, 3, 0, 3, 600, makecol(255, 255, 255)); 
     line(screen, 797, 0, 797, 600, makecol(255, 255, 255)); 

//  BATS 


     if(y>0&&y<400) 
     { 
      y=posy-100; 
     } 
     else if(y<=0) y=1; 
     else if(y>=400) y=399; 

     draw_sprite(screen,palki_bmp, 20, y); 

     if(y1>0&&y1<400) 
     { 
      y1=posy-100; 
     } 
     else if(y1<=0) y1=1; 
     else if(y1>=400) y1=399; 

     draw_sprite(screen,palki_bmp, 765, y1); 



//  COLLISION X-AXIS 

     if(check_posy==1) 
     { 
      if(posy<15) 
      { 
       posy=posy+SPEED; 
       check_posy=1; 
      } 
      else if(posy>585) 
      { 
       posy=posy-SPEED; 
       check_posy=2; 
      } 
      else posy=posy+SPEED; 
     } 
     else if(check_posy==2) 
     { 
      if(posy<15) 
      { 
       posy=posy+SPEED; 
       check_posy=1; 
      } 
      else if(posx>585) 
      { 
       posy=posy-SPEED; 
       check_posy=2; 
      } 
      else posy=posy-SPEED; 
     } 


//  COLLISION WITH BATS 

     if(check_posx==1) 
     { 
      if(posx<50&&posy>y&&posy<y+200) 
      { 
       SPEED=SPEED+3; 
       posx=posx+SPEED; 
       check_posx=1; 
       play_sample(tac,500, 100, 1000, 0); 
      } 
      else if(posx>750&&posy>y1&&posy<y1+200) 
      { 
       SPEED=SPEED+3; 
       posx=posx-SPEED; 
       check_posx=2; 
       play_sample(tac,500, 0, 1000, 0); 
      } 
      else posx=posx+SPEED; 
     } 
     else if(check_posx==2) 
     { 
      if(posx<50&&posy>y&&posy<y+200) 
      { 
       SPEED=SPEED+3; 
       posx=posx+SPEED; 
       check_posx=1; 
       play_sample(tac,500, 100, 1000, 0); 
      } 
      else if(posx>750&&posy>y1&&posy<y1+200) 
      { 
       SPEED=SPEED+3; 
       posx=posx-SPEED; 
       check_posx=2; 
       play_sample(tac,500, 0, 1000, 0); 
      } 
      else posx=posx-SPEED; 
     } 

     draw_sprite(screen,topce_bmp, posx-13, posy-10); 

     rest(10); 
    } 
    clear_to_color(screen,makecol(0,0,0)); 
    textout_centre_ex(screen, verdana, "PONG!",400,320, makecol(cred_anim,0,0),makecol(0,0,0)); 
    textout_centre_ex(screen, verdana, "Vistinska igra.",400, 420, makecol(cred_anim,cred_anim,cred_anim),makecol(0,0,0)); 
    rest(3000); 
    while(cred_anim!=0) 
    { 
     clear_to_color(screen,makecol(0,0,0)); 
     textout_centre_ex(screen, verdana, "PONG!",400,320, makecol(cred_anim,0,0),makecol(0,0,0)); 
     textout_centre_ex(screen, verdana, "Vistinska igra.",400, 420, makecol(cred_anim,cred_anim,cred_anim),makecol(0,0,0)); 
     cred_anim--; 
     rest(1); 
    } 
} 

Answer 1

只是关于代码的一些想法：

- 您调用acquire_screen（），但永远不会调用release_screen（）。这是坏的，not to mention all the warnings allegro gives you in the documentation for acquire_screen()。 “黑线”有点含糊不清（在何时，何地，何种程度上出现？），但根据您对clear_to_color（）的评论，直接绘制到屏幕上也可能是一个问题。似乎会导致问题。试试double buffering，即可以解决几个问题。

希望这会有所帮助。即使这些不能解决你的问题，他们仍然值得记住。