heisenbug

Article View: pl.comp.lang.c

Article #309513

#309513

From: (fir)
Date: Tue, 10 Oct 2017 18:44

53 lines
2457 bytes

trafilem na idiotycznego nuga mam mala petle w 
ktorej zadaniem jest jakby przesuniecie malego obszaru na bitmapie o pixel w dol (rozmiar np 8x8 te 8 pixeli
ktore wyjdzie z dolo na wejsc od gory w tym okienku

ten kod to cos takiego

void RollLetterBoxDown()
{
 int w = char_w;
 int h = char_h;
 int ch = selected_char;

  int px = ch%16;
  int py = ch/16;

  for(int j=0; j<h;j++)
   for(int i=0; i<w;i++)
   {
     tmp_box[j][i] = font_atlas[ (py*32+j)*32*16 + (px*32+i) ];
   }


  for(int j=0; j<h;j++)
  {
   for(int i=0; i<w;i++)
   {


     if(j==0)       font_atlas[ (py*32+j)*32*16 + (px*32+i) ] = tmp_box[h-1][i];
     if(j!=0)       font_atlas[ (py*32+j)*32*16 + (px*32+i) ] = tmp_box[j-1][i];

   }

   }


}


problem jest taki ze to wywoluje segfaulta (na tych ostatnich dwu linijkach)

natomiast jesli zakomentuje jedna z nich (niewazne ktora
to dziala 

dzial tez niz gruszki nie z pietruszki jesli dodam
Sleep(1) tuz po tych linijkach (w srodku petli)

co najdziwniejsze dziala tez gdy te dwie 'scale w 
jedną' czyli w cos takiego

         font_atlas[ (py*32+j)*32*16 + (px*32+i) ] = tmp_box[j==0?h-1:j-1][i];

absolutnie trudno mi pojac czemu skoro tamto sie sypie to to dziala?

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