Mouvment problem

Alright, I'm using Borland C++ Builder, and mostly its working aside from this small problem...

I have a Gameloop, where everything is handled(drawing, mouvment, etc) and FormKeyUp/Down functions to grab the key presses.

Whenever I move, it raised exceptions. This coded worked fine before I added the mouvment. To be able to move right or left, i need to wait until there has been a collision between a bullet and an enemy.(at the moment it just auto-shoots...) And mouvming up or down just doesn't work unless I hold the key down, and as soon as I let go, it raises the exception.

Here is the game loop:

Code:

---

void __fastcall TForm1::GameLoop(TObject*, bool &done)
{
// fires a regular shot
if(laser->y1 <= 0 || laser->Obsolete == true)
{
        laser->y1=User->y1;
        laser->Obsolete = false;
        laser->x1 =  User->x1 + User->Ship_Sprite->Width / 2;

      // PlaySound(MAKEINTRESOURCE(ID_LASER), HInstance, SND_RESOURCE | SND_ASYNC );
}

laser->regShot();

//check for collision
laser->Collision(Baddy,laser);

// fires a regular missile
if(missile->y1 <= 0 || missile->Obsolete == true)
{
        missile->y1=User->y1;
        missile->Obsolete = false;

        missile->x1 = User->x1 + User->Ship_Sprite->Width / 2;

}
missile->regShot();
missile->Collision(Baddy, missile);

  //move baddies
for(int k=1;k<5;k++)
{
        for(int z = 1;z<9;z++)
        {
                if(Baddy[k][z]->Dead == false)
                {
                        Baddy[k][z]->MoveLeft();
                        Baddy[k][z]->Baddy_Collision.top = Baddy[k][z]->x1;
                        Baddy[k][z]->Baddy_Collision.left = Baddy[k][z]->y1 + Baddy[k][z]->Enemy_Sprite->Height;
                        Baddy[k][z]->Baddy_Collision.Bottom = Baddy[k][z]->Baddy_Collision.left + Baddy[k][z]->Enemy_Sprite->Width;
                        Baddy[k][z]->Baddy_Collision.right = Baddy[k][z]->x1 + Baddy[k][z]->Enemy_Sprite->Width ;
              }
        }
}


/*for(int i=1;i<5;i++)
{
        for(int k=1;k<9;k++)
        {
          // BLaser->
        }
}  */

  //Key presses are acted upon here
  if (keys.right == true)
    {
      User->MoveRight();
    }

  if (keys.left == true)
    {
      User->MoveLeft();
    }

  if (keys.up == true)
  {
        User->MoveUp();
  }

  if (keys.down == true)
  {
  User->MoveDown();
  }



Draw(BackBuffer, User, Baddy, ClientRect, BackGround, laser, missile, Health);

done = false;

}

---

and the key up and down

Code:

---

oid __fastcall TForm1::FormKeyUp(TObject *Sender, WORD &Key, TShiftState Shift)
{
 if (Key == VK_RIGHT)  //move piece right
    {
        keys.right = false;
    }

  if (Key == VK_LEFT)
    {
    keys.left = false;
    }

  if (Key==VK_UP)
  {
    keys.up = false;
  }

  if (Key == VK_DOWN)
  {
    keys.down = false;
  }

}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormKeyDown(TObject *Sender, WORD &Key, TShiftState Shift)
{
 if (Key == VK_ESCAPE) Application->Terminate();

 if (Key == VK_RIGHT)  //move piece right
    {
        keys.right = true;
            }

  if (Key == VK_LEFT)
    {
    keys.left = true;
    }

  if (Key==VK_UP)
  {
    keys.up = true;
  }

  if (Key == VK_DOWN)
  {
    keys.down = true;
  }
}

---

Any help would be great!

Cheers,

DW

Which function raises the exception? Your debugger should tell you.

Here

Code:

---

Baddy[k][z]->Baddy_Collision.top = Baddy[k][z]->x1;

---

. This worked fine before I added the mouvment....

Cheers

It's a lot of work for someone else to step through your code for you. If I get time I will do it, but until then, I recommend you attempt it yourself. Set a breakpoint somewhere good and step through each line until you find a logic flaw or something like that. In this case 'k' and 'z' are obviously being set to values that Baddy[][] does not have memory allocated for, thus that line is attempting to access memory it doesn't own. Good luck.

I've been through it, um....lets see.....100 times now, spent 2 hrs on it. Like I said, the code *did* work, and now it doesn't, so I imagine the memeroy is still allocated properly. If you do have a chance, that would be amazing!

Cheers

DW

Alright, narrowed down the problem. its in how I created my stuct

Code:

---

struct key{bool left;
          bool right;
          bool up;
          bool down;};

---

when the last member (down) is acsessed, it crashes.

Is there somthing wrong with how i declared this?

DW

Quote:

---

so I imagine the memeroy is still allocated properly.

---

Exceptions (in this case an access violation) occur when memory isn't allocated properly, or when you specify an index for an array that points to memory you haven't allocated. I am very sure it is memory related here.

Quote:

---

If you do have a chance, that would be amazing!

---

I might do it within the next few hours.

Quote:

---

Is there somthing wrong with how i declared this?

---

Looks fine to me. However, if it crashes when you access the last data member, we could infer that the bounds of your array are off by a tiny amount, a common problem that occurs using lots of loops and arrays. You probably should have allocated 'something+1' bytes of memory or something like that somewhere.

Anyway, I'll step through the code and see what I come up with.

EDIT: Actually, I'm going to need all of your code if I'm going to debug it. I imagine it's quite big so just zip the entire project folder and email it to me: [email protected]

EDIT: Can you also show me exactly which lines cause your exception? Is it every time you access Key::down?

Sure I'll send it. Its made with Borland C++ Builder. Do you have this?


thx again
DW

Hasn't your problem just been solved in the other thread?

ah.....no not really....kinda.....i'll post there.