libcruft-util/region.cpp
Danny Robson ec0cb7d2c1 region: remove scale operation
it's not immediately apparent how scale operates on both of point and
extent components. rather than complicate matters we remove them in
preference of letting the user construct it directly.
2017-08-11 15:20:48 +10:00

330 lines
8.2 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 2010-2017 Danny Robson <danny@nerdcruft.net>
*/
#include "./region.hpp"
#include "./debug.hpp"
#include "./coord/iostream.hpp"
#include <array>
using util::region;
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>::region (extent_t _extent):
region (point_t::origin (), _extent)
{
debug::sanity (*this);
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>::region (point_t _p,
extent_t _e):
p (_p),
e (_e)
{
debug::sanity (*this);
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>::region (point_t _a,
point_t _b):
region (_a, extent_t { _b - _a })
{
// This check must allow for zero area (but non-zero dimension) regions.
// Some code paths need to support this degenerate case. It's ugly but
// simplifies generalisation. eg, vertical linear bezier curves.
CHECK (all (_a <= _b));
debug::sanity (*this);
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
T
util::region<S,T>::area (void) const
{
return e.area ();
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
T
util::region<S,T>::diameter (void) const
{
return e.diameter ();
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::extent_t
util::region<S,T>::magnitude (void) const
{
return e;
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::extent_t
util::region<S,T>::magnitude (extent_t _e)
{
e = _e;
return e;
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
bool
util::region<S,T>::empty (void) const
{
return almost_zero (area ());
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::point_t
util::region<S,T>::base (void) const
{
return p;
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::point_t
util::region<S,T>::away (void) const
{
return p + e;
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::point_t
util::region<S,T>::centre (void) const
{
return p + e / T{2};
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename util::region<S,T>::point_t
util::region<S,T>::closest (point_t q) const
{
point_t out;
for (size_t i = 0; i < S; ++i)
out[i] = q[i] < p[i] ? p[i] :
q[i] > p[i] ? p[i] + e[i] :
q[i];
return out;
}
//-----------------------------------------------------------------------------
// FIXME: This will fail with an actual infinite range (NaNs will be generated
// in the conditionals).
template <size_t S, typename T>
bool
util::region<S,T>::intersects (region<S,T> rhs) const
{
for (size_t i = 0; i < S; ++i)
if ( p[i] >= rhs.p[i] + rhs.e[i] ||
rhs.p[i] >= p[i] + e[i])
{ return false; }
return true;
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
typename region<S,T>::point_t
region<S,T>::constrain (point_t q) const noexcept
{
for (size_t i = 0; i < S; ++i)
q[i] = limit (q[i], p[i], p[i] + e[i]);
return q;
}
//-----------------------------------------------------------------------------
template<size_t S, typename T>
util::region<S,T>
util::region<S,T>::intersection (region<S,T> rhs) const
{
// find the intersection corners
point_t a, b;
for (size_t i = 0; i < S; ++i) {
a[i] = util::max (p[i], rhs.p[i]);
b[i] = util::min (p[i] + e[i], rhs.p[i] + rhs.e[i]);
if (b[i] < a[i])
throw std::logic_error ("no overlap");
}
return { a, b };
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
bool
util::region<S,T>::covers (region<S, T> r) const noexcept
{
return all (p <= r.p) && all (p + e >= r.p + r.e);
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
bool
region<S,T>::covers (const point<S,T> q) const noexcept
{
return all (p <= q) && all (p + e >= q);
}
///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::inset (T mag) const
{
return inset (util::vector<S,T> {mag});
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::inset (vector<S,T> mag) const
{
// ensure we have enough space to trim off our total extent
CHECK (all (e >= 2 * mag));
return {
p + mag,
e - T{2} * mag
};
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::expand (vector<S,T> v) const
{
return {
p - v,
e + v * T{2}
};
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::expand (T mag) const
{
return expand (vector<S,T> {mag});
}
///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::operator+ (vector<S,T> rhs) const
{
return { p + rhs, e };
}
//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::region<S,T>
util::region<S,T>::operator- (vector<S,T> rhs) const
{
return { p - rhs, e };
}
///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
bool
util::region<S,T>::operator== (region rhs) const
{
return p == rhs.p && e == rhs.e;
}
///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
std::ostream&
util::operator<< (std::ostream &os, const util::region<S,T> &rhs) {
return os << "{ position: " << rhs.p << ", extent: " << rhs.e << " }";
}
///////////////////////////////////////////////////////////////////////////////
namespace util::debug {
template <size_t S, typename T>
struct validator<util::region<S,T>> {
static bool is_valid (const util::region<S,T> &r)
{
return util::debug::is_valid (r.p) && util::debug::is_valid (r.e);
}
};
}
///////////////////////////////////////////////////////////////////////////////
#define INSTANTIATE_S_T(S,T) \
template struct util::region<S,T>; \
template std::ostream& util::operator<< (std::ostream&, const region<S,T>&); \
template struct util::debug::validator<util::region<S,T>>;
#define INSTANTIATE(T) \
INSTANTIATE_S_T(2,T) \
INSTANTIATE_S_T(3,T)
INSTANTIATE(int16_t);
INSTANTIATE(int32_t);
INSTANTIATE(int64_t);
INSTANTIATE(uint16_t)
INSTANTIATE(uint32_t)
INSTANTIATE(uint64_t)
INSTANTIATE(float)
INSTANTIATE(double)