相邻的小区的一个角视场的选择
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13-09-2019 - |
题
试想用3名维六方晶的空间。
每个瓦片具有坐标XYZ。 我需要在同一平面上选择一个给定的小区邻居。 随着SQL它看起来像:
$tbDir = $y % 2 == 0 ? -1 : 1;
$result = db_query('SELECT x,y,z FROM {cells} WHERE
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d OR
x = %d AND y = %d AND z = %d ',
$x, $y, $z,
$x-1, $y, $z,
$x+1, $y, $z,
$x, $y-1, $z,
$x, $y+1, $z,
$x+$tbDir, $y-1, $z,
$x+$tbDir, $y+1, $z);
不过,我不喜欢这种方式。 也许有人知道更优化的算法? 谢谢!
解决方案
这貌似可以
之间使用x BETWEEN $x-1 AND $x+1 AND y BETWEEN $y-1 AND $y+1 AND z = $z
这也许不完全为$ tbDir部分工作。我将看看这种情况下更详细地
行,而尝试此
WHERE x BETWEEN ($x-1 AND $x+1 AND y = $y AND z = $z)
OR (y BETWEEN $y-1 AND $y+1 AND x = $x AND z = $z)
OR (y BETWEEN $y-1 AND $y+1 AND x = $x + $tbDir AND z = $z)
或甚至
WHERE ( (x BETWEEN $x-1 AND $x+1 AND y = $y )
OR (y BETWEEN $y-1 AND $y+1 AND x = $x)
OR (y BETWEEN $y-1 AND $y+1 AND x = $x + $tbDir)
)
AND z = $z
其他提示
有一个简单的映射,如果您的算法可以用非正交坐标系统中工作。在你的情况下,六角瓦片其平行于轴的部分似乎是垂直:
/ \ / \ / \
| a | b | c |
\ / \ / \ / \
| d | e | f |
/ \ / \ / \ /
| x | g | h | i
如果可以接受的偏斜Y轴,那么也可以把a
,d
,g
X坐标0(即,Y轴穿过这些砖的中心)。 (beh
将具有X == 1,cfi
具有X == 2等)。 x
已坐标(-1,2)。现在你可以这样移动:
e -> f: x+1,y
e -> d: x-1,y
e -> b: x, y-1
e -> c: x+1,y-1
e -> g: x-1,y+1
e -> h: x, y+1
可以看到,现在的动作是完全独立的y位置的
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