Geometry Boost List: [ggl] (spatial_)index::is_overlapping

Subject: [ggl] (spatial_)index::is_overlapping
From: Mateusz Loskot (mateusz)
Date: 2009-06-18 19:39:34

Barend Gehrels wrote:
> Hi Chris,
> 
>> I've simplified the function to this:
>>
>>     template <typename Box>
>>     inline bool is_overlapping(Box const& b1, Box const& b2)
>>     {
>>         if (ggl::get<min_corner, 0>(b1) > ggl::get<max_corner, 0>(b2))
>>             return false
>>
>>         if (ggl::get<max_corner, 0>(b1) < ggl::get<min_corner, 0>(b2))
>>             return false;
>>
>>         if (ggl::get<min_corner, 1>(b1) > ggl::get<max_corner, 1>(b2))
>>             return false;
>>
>>         if (ggl::get<max_corner, 1>(b1) < ggl::get<min_corner, 1>(b2))
>>             return false;
>>
>>         return true;
>>     }
>>
>>
>> This should dramatically reduce the numbers of "get". Do you see an
>> obvious flaw?
>>
> OK and much better than what I just checked in, and somewhat faster.

Barend,

Just a side note, How do we know that?

These accessors are very good candidates to be completely optimized out
and then no function calls will occur.

Cheers
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org