libcruft-util/geom/aabb.hpp
Danny Robson 95d13b9fe4 geom/aabb: rename p0,p1 to lo,hi
this makes their meaning more explicit
2018-03-13 15:42:29 +11:00

143 lines
3.8 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2015-2017 Danny Robson <danny@nerdcruft.net>
*/
#ifndef CRUFT_UTIL_GEOM_AABB_HPP
#define CRUFT_UTIL_GEOM_AABB_HPP
#include "../debug.hpp"
#include "../extent.hpp"
#include "../point.hpp"
#include <cstdint>
namespace util::geom {
///////////////////////////////////////////////////////////////////////////
/// represents an axis-aligned bounding-box through two opposing corners.
///
/// `lo' must be less-than-or-equal to `hi'. equality is allowed so that
/// we can represent zero sized bounding-boxes.
template <size_t S, typename T>
struct aabb {
aabb () = default;
aabb (point<S,T> _lo, point<S,T> _hi):
lo (_lo),
hi (_hi)
{
CHECK (all (lo <= hi));
}
///////////////////////////////////////////////////////////////////////
extent<S,T>
magnitude (void) const
{
return (hi - lo).template as<util::extent> ();
}
//---------------------------------------------------------------------
T
diameter (void) const
{
return magnitude ().diameter ();
}
//---------------------------------------------------------------------
/// tests whether a point lies within the region, inclusive of borders
constexpr bool
inclusive (point<S,T> p) const noexcept
{ return all (lo <= p && hi >= p); }
//---------------------------------------------------------------------
point<S,T>
closest (point<S,T> query) const
{
return limit (query, lo, hi);
}
//---------------------------------------------------------------------
void cover (point<S,T> p)
{
lo = min (p, lo);
hi = max (p, hi);
}
//---------------------------------------------------------------------
aabb<S,T> operator+ (vector<S,T> v) const
{
return { lo + v, hi + v };
}
aabb<S,T> operator- (vector<S,T> v) const
{
return { lo - v, hi - v };
}
::util::point<S,T> lo;
::util::point<S,T> hi;
};
///////////////////////////////////////////////////////////////////////////
template <std::size_t S, typename T>
constexpr bool
operator== (const aabb<S,T> &a, const aabb<S,T> &b) noexcept
{
return a.lo == b.lo && a.hi == b.hi;
}
///////////////////////////////////////////////////////////////////////////
typedef aabb<2,float> aabb2f;
typedef aabb<2,unsigned> aabb2u;
typedef aabb<2,int> aabb2i;
typedef aabb<3,float> aabb3f;
typedef aabb<3,unsigned> aabb3u;
typedef aabb<3,int> aabb3i;
}
///////////////////////////////////////////////////////////////////////////////
#include "./sample.hpp"
#include <random>
namespace util::geom {
template <size_t S, typename T, typename G>
struct sampler<S,T,aabb,G> {
static point<S,T>
fn (aabb<S,T> b, G &g)
{
std::uniform_real_distribution<T> d;
point<S,T> p;
std::generate (p.begin (), p.end (), [&] (void) { return d (g); });
return p * (b.hi - b.lo) + b.lo.template as<util::vector> ();
}
};
}
#endif