Difference between revisions of "GetDistanceInTiles"

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m (Protected "GetDistanceInTiles" ([edit=sysop] (indefinite) [move=sysop] (indefinite)))
 
(One intermediate revision by the same user not shown)
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integer getDistanceInTiles(location A, location B)
 
integer getDistanceInTiles(location A, location B)
 
{
 
{
   // NOTE TO SELF: I should clear this up when I'm not so sleepy
+
   // NOTE TO SELF: I should explain this better when I'm not so sleepy
   tmpx = A.x >= 5120 ? 1 : 0;
+
   Ax_is_invalid = A.x >= 5120 ? 1 : 0;
   tmpy = B.x >= 5120 ? 1 : 0;
+
   Bx_is_invalid = B.x >= 5120 ? 1 : 0;
   if(tmpx ^ tmpy != 0)
+
   if(Ax_is_invalid ^ Bx_is_invalid != 0) // Indeed, XOR is used here
 
     return 9999;
 
     return 9999;
  

Latest revision as of 22:44, 14 April 2010

integer getDistanceInTiles(location A, location B);

This function will calculate the absolute value of the difference between A and B (for both x and y) and the highest value of the two is returned. The Z value is ignored when calculating the difference.

Pseudo-code (using signed integers):
integer getDistanceInTiles(location A, location B)
{
  // NOTE TO SELF: I should explain this better when I'm not so sleepy
  Ax_is_invalid = A.x >= 5120 ? 1 : 0;
  Bx_is_invalid = B.x >= 5120 ? 1 : 0;
  if(Ax_is_invalid ^ Bx_is_invalid != 0) // Indeed, XOR is used here
    return 9999;

  Xdiff = A.x - B.x;
  ydiff = A.y - B.y;
  
  if(xdiff < 0)
    xdiff = -xdiff;
  if(ydiff < 0)
    ydiff = -ydiff;

  if(A.x < 5120)
  {
    if(5120 - xdiff > xdiff)
      xdiff = 5120 - xdiff;
    if(4096 - ydiff > ydiff)
      ydiff = 4096 - ydiff;
  }

  if(xdiff > ydiff)
    retval = xdiff;
  else
    retval = ydiff;

  return retval;
}

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