我一直在尝试编程我在网上找到的各种A star算法，尽管它们很有意义，但是我编程的每个实现都失败了。
这是我的免费Pascal代码：
function getHeuristic(currentXY, targetXY: array of word): word;
begin
getHeuristic:=abs(currentXY[0]-targetXY[0])+abs(currentXY[1]-targetXY[1]);
end;
function getPath(startingNodeXY, targetNodeXY: array of word; grid: wordArray3; out pathToControlledCharPtr: word; worldObjIndex: word): wordArray2;
var
openList, closedList: array of array of word; { x/y/g/h/parent x/parent y, total }
qXYGH: array[0..5] of word; { x/y/g/h/parent x/parent y }
gridXCnt, gridYCnt: longInt;
maxF, q, openListCnt, closedListCnt, parentClosedListCnt, getPathCnt, adjSquNewGScore: word;
openListIndexCnt, closedListIndexCnt, qIndexCnt, successorIndexCnt: byte;
getMaxF, successorOnClosedList, successorOnOpenList, pathFound: boolean;
begin
{ Add the starting square (or node) to the open list. }
setLength(openList, 6, length(openList)+1);
openList[0, 0]:=startingNodeXY[0];
openList[1, 0]:=startingNodeXY[1];
setLength(closedList, 6, 0);
{ Repeat the following: }
{ D) Stop when you: }
{ Fail to find the target square, and the open list is empty. In this case, there is no path. }
pathFound:=false;
{ writeLn('h1'); }
while length(openList[0])>0 do
begin
{ A) Look for the lowest F cost square on the open list. We refer to this as the current square. }
maxF:=0;
q:=0;
getMaxF:=true;
for openListCnt:=0 to length(openList[0])-1 do
begin
//writeLn(formatVal('open list xy {} {}, cnt {}, list max index {}', [openList[0, openListCnt], openList[1, openListCnt], openListCnt, length(openList[0])-1]));
{ readLnPromptX; }
if (getMaxF=true) or (maxF>openList[2, openListCnt]+openList[3, openListCnt]) then
begin
getMaxF:=false;
maxF:=openList[2, openListCnt]+openList[3, openListCnt];
q:=openListCnt;
end;
end;
for qIndexCnt:=0 to length(qXYGH)-1 do
qXYGH[qIndexCnt]:=openList[qIndexCnt, q];
{ B). Switch it to the closed list. }
setLength(closedList, length(closedList), length(closedList[0])+1);
for closedListIndexCnt:=0 to length(closedList)-1 do
closedList[closedListIndexCnt, length(closedList[0])-1]:=qXYGH[closedListIndexCnt];
{ Remove current square from open list }
if q<length(openList[0])-1 then
begin
for openListCnt:=q to length(openList[0])-2 do
begin
for openListIndexCnt:=0 to length(openList)-1 do
openList[openListIndexCnt, openListCnt]:=openList[openListIndexCnt, openListCnt+1];
end;
end;
setLength(openList, length(openList), length(openList[0])-1);
//writeLn(formatVal('q[x] {}, q[y] {}, startingNodeXY x {}, startingNodeXY y {}, targetNodeXY x {}, targetNodeXY y {}', [qXYGH[0], qXYGH[1], startingNodeXY[0], startingNodeXY[1], targetNodeXY[0], targetNodeXY[1]]));
{ readLnPromptX; }
{ D) Stop when you: }
{ Add the target square to the closed list, in which case the path has been found, or }
if (qXYGH[0]=targetNodeXY[0]) and (qXYGH[1]=targetNodeXY[1]) then
begin
pathFound:=true;
break;
end;
{ C) For each of the 8 squares adjacent to this current square … }
for gridXCnt:=qXYGH[0]-1 to qXYGH[0]+1 do
begin
for gridYCnt:=qXYGH[1]-1 to qXYGH[1]+1 do
begin
{ Adjacent square cannot be the current square }
if (gridXCnt<>qXYGH[0]) or (gridYCnt<>qXYGH[1]) then
begin
//writeLn(formatVal('gridXCnt {} gridYCnt {} qXYGH[0] {} qXYGH[1] {}', [gridXCnt, gridYCnt, qXYGH[0], qXYGH[1]]));
{ readLnPromptX; }
{ Check if successor is on closed list }
successorOnClosedList:=false;
if length(closedList[0])>0 then
begin
for closedListCnt:=0 to length(closedList[0])-1 do
begin
if (closedList[0, closedListCnt]=gridXCnt) and (closedList[1, closedListCnt]=gridYCnt) then
begin
successorOnClosedList:=true;
break;
end;
end;
end;
{ If it is not walkable or if it is on the closed list, ignore it. Otherwise do the following. }
if (gridXCnt>=0) and (gridXCnt<=length(grid[3])-1) and (gridYCnt>=0) and (gridYCnt<=length(grid[3, 0])-1) and (grid[3, gridXCnt, gridYCnt]=0) and (successorOnClosedList=false) then
begin
{ If it isn’t on the open list, add it to the open list. Make the current square the parent of this square. Record the F, G, and H costs of the square. }
successorOnOpenList:=false;
if length(openList[0])>0 then
begin
for openListCnt:=0 to length(openList[0])-1 do
begin
if (openList[0, openListCnt]=gridXCnt) and (openList[1, openListCnt]=gridYCnt) then
begin
successorOnOpenList:=true;
break;
end;
end;
end;
if successorOnOpenList=false then
begin
setLength(openList, length(openList), length(openList[0])+1);
openList[0, length(openList[0])-1]:=gridXCnt;
openList[1, length(openList[0])-1]:=gridYCnt;
openList[4, length(openList[0])-1]:=qXYGH[0];
openList[5, length(openList[0])-1]:=qXYGH[1];
if (openList[0, length(openList[0])-1]=qXYGH[0]) or (openList[1, length(openList[0])-1]=qXYGH[1]) then
begin
openList[2, length(openList[0])-1]:=openList[2, length(openList[0])-1]+10;
end
else
begin
openList[2, length(openList[0])-1]:=openList[2, length(openList[0])-1]+14;
end;
openList[3, length(openList[0])-1]:=getHeuristic([openList[0, length(openList[0])-1], openList[1, length(openList[0])-1]], [targetNodeXY[0], targetNodeXY[1]]);
end
else
begin
{ If it is on the open list already, check to see if this path to that square is better, using G cost as the measure (check to see if the G score for the adjacent square is lower if we use the current square to get there (adjacent square
new G score = current square G score + 10 (if adjacent squre is vertical or horizontal to current square) or +14 (if it is diagonal); if result is lower than adjacent square current G score then this path is better). A lower G cost means that
this is a better path. If so, change the parent of the square to the current square, and recalculate the G and F scores of the square. If you are keeping your open list sorted by F score, you may need to resort the list to account for the
change. }
adjSquNewGScore:=openList[2, openListCnt];
if (openList[0, openListCnt]=qXYGH[0]) or (openList[1, openListCnt]=qXYGH[1]) then
begin
adjSquNewGScore:=adjSquNewGScore+10;
end
else
begin
adjSquNewGScore:=adjSquNewGScore+14;
end;
if adjSquNewGScore<openList[2, openListCnt] then
begin
openList[4, openListCnt]:=qXYGH[0];
openList[5, openListCnt]:=qXYGH[1];
openList[2, openListCnt]:=adjSquNewGScore;
end;
end;
end;
end;
end;
end;
end;
{ writeLn('h2'); }
{ writeLn(pathFound); }
{ readLnHalt; }
if pathFound=true then
begin
{ Save the path. Working backwards from the target square, go from each square to its parent square until you reach the starting square. That is your path. }
closedListCnt:=length(closedList[0])-1;
setLength(getPath, 2, 0);
{ While starting node has not been added to path }
while (length(getPath[0])=0) or (getPath[0, length(getPath[0])-1]<>startingNodeXY[0]) or (getPath[1, length(getPath[0])-1]<>startingNodeXY[1]) do
begin
{ Add node from closed list to path }
setLength(getPath, 2, length(getPath[0])+1);
getPath[0, length(getPath[0])-1]:=closedList[0, closedListCnt];
getPath[1, length(getPath[0])-1]:=closedList[1, closedListCnt];
{ Find next node on closed list with coord matching parent coord of current closed list node }
for parentClosedListCnt:=length(closedList[0])-1 downto 0 do
if (closedList[0, parentClosedListCnt]=closedList[4, closedListCnt]) and (closedList[1, parentClosedListCnt]=closedList[5, closedListCnt]) then break;
closedListCnt:=parentClosedListCnt;
{ if (closedList[0, closedListCnt]=0) and (closedList[1, closedListCnt]=0) then break; }
end;
pathToControlledCharPtr:=length(getPath[0])-1;
end;
end;
我正在执行的步骤是：
将起始方块（或节点）添加到打开列表中。
重复以下内容：
A）在打开的列表中寻找最低的F成本平方。我们将此称为当前正方形。
B）。将其切换到关闭列表。
C）对于与该当前正方形相邻的8个正方形中的每一个……
D）在以下情况下停止：
已解决！
这是工作代码：
function getHeuristic(currentXY, targetXY: array of word): word;
begin
getHeuristic:=abs(currentXY[0]-targetXY[0])+abs(currentXY[1]-targetXY[1]);
end;
function getPath(startingNodeXY, targetNodeXY: array of word; grid: wordArray3; out pathToControlledCharPtr: word; worldObjIndex: word): wordArray2;
var
openList, closedList: array of array of word; { x/y/g/h/parent x/parent y, total }
qXYGH: array[0..5] of word; { x/y/g/h/parent x/parent y }
gridXCnt, gridYCnt: longInt;
maxF, q, openListCnt, closedListCnt, parentClosedListCnt, getPathCnt, adjSquNewGScore: word;
openListIndexCnt, closedListIndexCnt, qIndexCnt, successorIndexCnt: byte;
getMaxF, successorOnClosedList, successorOnOpenList, pathFound: boolean;
begin
{ Add the starting square (or node) to the open list. }
setLength(openList, 6, length(openList)+1);
openList[0, 0]:=startingNodeXY[0];
openList[1, 0]:=startingNodeXY[1];
setLength(closedList, 6, 0);
{ Repeat the following: }
{ D) Stop when you: }
{ Fail to find the target square, and the open list is empty. In this case, there is no path. }
pathFound:=false;
{ writeLn('h1'); }
while length(openList[0])>0 do
begin
{ A) Look for the lowest F cost square on the open list. We refer to this as the current square. }
maxF:=0;
q:=0;
getMaxF:=true;
for openListCnt:=0 to length(openList[0])-1 do
begin
//writeLn(formatVal('open list xy {} {}, cnt {}, list max index {}', [openList[0, openListCnt], openList[1, openListCnt], openListCnt, length(openList[0])-1]));
{ readLnPromptX; }
if (getMaxF=true) or (maxF>openList[2, openListCnt]+openList[3, openListCnt]) then
begin
getMaxF:=false;
maxF:=openList[2, openListCnt]+openList[3, openListCnt];
q:=openListCnt;
end;
end;
for qIndexCnt:=0 to length(qXYGH)-1 do
qXYGH[qIndexCnt]:=openList[qIndexCnt, q];
{ B). Switch it to the closed list. }
setLength(closedList, length(closedList), length(closedList[0])+1);
for closedListIndexCnt:=0 to length(closedList)-1 do
closedList[closedListIndexCnt, length(closedList[0])-1]:=qXYGH[closedListIndexCnt];
{ Remove current square from open list }
if q<length(openList[0])-1 then
begin
for openListCnt:=q to length(openList[0])-2 do
begin
for openListIndexCnt:=0 to length(openList)-1 do
openList[openListIndexCnt, openListCnt]:=openList[openListIndexCnt, openListCnt+1];
end;
end;
setLength(openList, length(openList), length(openList[0])-1);
//writeLn(formatVal('q[x] {}, q[y] {}, startingNodeXY x {}, startingNodeXY y {}, targetNodeXY x {}, targetNodeXY y {}', [qXYGH[0], qXYGH[1], startingNodeXY[0], startingNodeXY[1], targetNodeXY[0], targetNodeXY[1]]));
{ readLnPromptX; }
{ D) Stop when you: }
{ Add the target square to the closed list, in which case the path has been found, or }
if (qXYGH[0]=targetNodeXY[0]) and (qXYGH[1]=targetNodeXY[1]) then
begin
pathFound:=true;
break;
end;
{ C) For each of the 8 squares adjacent to this current square … }
for gridXCnt:=qXYGH[0]-1 to qXYGH[0]+1 do
begin
for gridYCnt:=qXYGH[1]-1 to qXYGH[1]+1 do
begin
{ Adjacent square cannot be the current square }
if (gridXCnt<>qXYGH[0]) or (gridYCnt<>qXYGH[1]) then
begin
//writeLn(formatVal('gridXCnt {} gridYCnt {} qXYGH[0] {} qXYGH[1] {}', [gridXCnt, gridYCnt, qXYGH[0], qXYGH[1]]));
{ readLnPromptX; }
{ Check if successor is on closed list }
successorOnClosedList:=false;
if length(closedList[0])>0 then
begin
for closedListCnt:=0 to length(closedList[0])-1 do
begin
if (closedList[0, closedListCnt]=gridXCnt) and (closedList[1, closedListCnt]=gridYCnt) then
begin
successorOnClosedList:=true;
break;
end;
end;
end;
{ If it is not walkable or if it is on the closed list, ignore it. Otherwise do the following. }
if (gridXCnt>=0) and (gridXCnt<=length(grid[3])-1) and (gridYCnt>=0) and (gridYCnt<=length(grid[3, 0])-1) and (grid[3, gridXCnt, gridYCnt]=0) and (successorOnClosedList=false) then
begin
{ If it isn’t on the open list, add it to the open list. Make the current square the parent of this square. Record the F, G, and H costs of the square. }
successorOnOpenList:=false;
if length(openList[0])>0 then
begin
for openListCnt:=0 to length(openList[0])-1 do
begin
if (openList[0, openListCnt]=gridXCnt) and (openList[1, openListCnt]=gridYCnt) then
begin
successorOnOpenList:=true;
break;
end;
end;
end;
if successorOnOpenList=false then
begin
setLength(openList, length(openList), length(openList[0])+1);
openList[0, length(openList[0])-1]:=gridXCnt;
openList[1, length(openList[0])-1]:=gridYCnt;
openList[4, length(openList[0])-1]:=qXYGH[0];
openList[5, length(openList[0])-1]:=qXYGH[1];
if (openList[0, length(openList[0])-1]=qXYGH[0]) or (openList[1, length(openList[0])-1]=qXYGH[1]) then
begin
openList[2, length(openList[0])-1]:=openList[2, length(openList[0])-1]+10;
end
else
begin
openList[2, length(openList[0])-1]:=openList[2, length(openList[0])-1]+14;
end;
openList[3, length(openList[0])-1]:=getHeuristic([openList[0, length(openList[0])-1], openList[1, length(openList[0])-1]], [targetNodeXY[0], targetNodeXY[1]]);
end
else
begin
{ If it is on the open list already, check to see if this path to that square is better, using G cost as the measure (check to see if the G score for the adjacent square is lower if we use the current square to get there (adjacent square
new G score = current square G score + 10 (if adjacent squre is vertical or horizontal to current square) or +14 (if it is diagonal); if result is lower than adjacent square current G score then this path is better). A lower G cost means that
this is a better path. If so, change the parent of the square to the current square, and recalculate the G and F scores of the square. If you are keeping your open list sorted by F score, you may need to resort the list to account for the
change. }
adjSquNewGScore:=openList[2, openListCnt];
if (openList[0, openListCnt]=qXYGH[0]) or (openList[1, openListCnt]=qXYGH[1]) then
begin
adjSquNewGScore:=adjSquNewGScore+10;
end
else
begin
adjSquNewGScore:=adjSquNewGScore+14;
end;
if adjSquNewGScore<openList[2, openListCnt] then
begin
openList[4, openListCnt]:=qXYGH[0];
openList[5, openListCnt]:=qXYGH[1];
openList[2, openListCnt]:=adjSquNewGScore;
end;
end;
end;
end;
end;
end;
end;
{ writeLn('h2'); }
{ writeLn(pathFound); }
{ readLnHalt; }
if pathFound=true then
begin
{ Save the path. Working backwards from the target square, go from each square to its parent square until you reach the starting square. That is your path. }
closedListCnt:=length(closedList[0])-1;
setLength(getPath, 2, 0);
{ While starting node has not been added to path }
while (length(getPath[0])=0) or (getPath[0, length(getPath[0])-1]<>startingNodeXY[0]) or (getPath[1, length(getPath[0])-1]<>startingNodeXY[1]) do
begin
{ Add node from closed list to path }
setLength(getPath, 2, length(getPath[0])+1);
getPath[0, length(getPath[0])-1]:=closedList[0, closedListCnt];
getPath[1, length(getPath[0])-1]:=closedList[1, closedListCnt];
//writeLn(formatVal('path found {} {}, start {} {}, target {} {}', [getPath[0, length(getPath[0])-1], getPath[1, length(getPath[0])-1], startingNodeXY[0], startingNodeXY[1], targetNodeXY[0], targetNodeXY[1]]));
{ readLnPromptX; }
{ Find next node on closed list with coord matching parent coord of current closed list node }
for parentClosedListCnt:=length(closedList[0])-1 downto 0 do
if (closedList[0, parentClosedListCnt]=closedList[4, closedListCnt]) and (closedList[1, parentClosedListCnt]=closedList[5, closedListCnt]) then break;
closedListCnt:=parentClosedListCnt;
{ if (closedList[0, closedListCnt]=0) and (closedList[1, closedListCnt]=0) then break; }
end;
pathToControlledCharPtr:=length(getPath[0])-1;
end;
end;