libcruft-util/geom/aabb.hpp

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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
* Copyright 2015-2017 Danny Robson <danny@nerdcruft.net>
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*/
#ifndef CRUFT_UTIL_GEOM_AABB_HPP
#define CRUFT_UTIL_GEOM_AABB_HPP
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#include "../debug.hpp"
#include "../extent.hpp"
#include "../point.hpp"
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#include <cstdint>
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namespace cruft::geom {
///////////////////////////////////////////////////////////////////////////
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/// 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.
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template <size_t S, typename T>
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struct aabb {
aabb () = default;
aabb (point<S,T> _lo, point<S,T> _hi):
lo (_lo),
hi (_hi)
{
CHECK (all (lo <= hi));
}
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///////////////////////////////////////////////////////////////////////
extent<S,T>
magnitude (void) const
{
return (hi - lo).template as<cruft::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
{
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return clamp (query, lo, hi);
}
//---------------------------------------------------------------------
void cover (point<S,T> p)
{
lo = min (p, lo);
hi = max (p, hi);
}
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//---------------------------------------------------------------------
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 };
}
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/// returns an aabb that covers the supplied point in addition to the
/// current aabb area.
auto operator| [[nodiscard]] (point<S,T> p) const noexcept
{
return aabb (
cruft::min (lo, p),
cruft::max (hi, p)
);
}
auto& operator|= (point<S,T> p) noexcept
{
return *this = *this | p;
}
aabb operator| [[nodiscard]] (aabb<S,T> rhs) const noexcept
{
return {
min (lo, rhs.lo),
max (hi, rhs.hi)
};
}
std::array<cruft::point<S,T>,cruft::pow(2,S)>
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vertices (void) const noexcept;
::cruft::point<S,T> lo;
::cruft::point<S,T> hi;
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};
///////////////////////////////////////////////////////////////////////////
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;
}
///////////////////////////////////////////////////////////////////////////
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typedef aabb<2,float> aabb2f;
typedef aabb<2,unsigned> aabb2u;
typedef aabb<2,int> aabb2i;
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typedef aabb<3,float> aabb3f;
typedef aabb<3,unsigned> aabb3u;
typedef aabb<3,int> aabb3i;
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}
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///////////////////////////////////////////////////////////////////////////////
#include "./sample.hpp"
#include <random>
namespace cruft::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<cruft::vector> ();
}
};
}
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#endif