Author: Christophe Theron
Date: 03:55:08 06/14/00
Go up one level in this thread
On June 14, 2000 at 03:03:22, Peter Kappler wrote:
>On June 13, 2000 at 23:10:51, Christophe Theron wrote:
>
>>On June 13, 2000 at 17:06:57, Tom Kerrigan wrote:
>>
>>>On June 13, 2000 at 16:10:05, Christophe Theron wrote:
>>>
>>>>With the other approach, you need a table lookup to tell that the square is not
>>>>inside the board:
>>>>
>>>> // 12x12 way:
>>>> if (board[square]==-1) it_is_outside;
>>>> else it_is_inside;
>>>
>>>If your board starts out being 12x12, then you're right, it doesn't really make
>>>a difference if you switch to 0x88.
>>>
>>>However, I know that a number of programs use an 8x8 board. To do the bounds
>>>testing, they convert the 8x8 offset into a 10x12 offset and then back again.
>>>You can see this done in TSCP. This method is obviously a loser compared to
>>>0x88.
>>
>>
>>I don't really understand why you would use a 8x8 board if you use 12x12
>>coordinates or the opposite...
>>
>>Actually I'm using 16x16 coordinates, so I shouldn't have mentionned 12x12 or
>>12x10, but just 16x16 (well actually I just need 16x12).
>>
>>I think 16x16 is more efficient than 0x88 and I explained why. And it is much
>>simpler to understand than 0x88 BTW! The way you test the out of bound condition
>>in 0x88 is great, but that's the only advantage of this system, and as I
>>explained nobody cares for this test most of the time!
>>
>>
>> Christophe
>
>
>What makes 16x12 better than 12x12? I'm sure it allows for some clever bitwise
>operations somewhere, but I don't quite get it...
>
>--Peter
You are right, there are a lot of smart things to do with 16x16 (or 16x12). For
example knowing easily if a square is a corner, in the center, and a lot of
other nice stuffs.
Christophe
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