69 lines
1.9 KiB
C++
69 lines
1.9 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 2018 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#ifndef CRUFT_UTIL_GEOM_FRUSTUM_HPP
|
|
#define CRUFT_UTIL_GEOM_FRUSTUM_HPP
|
|
|
|
#include "../matrix.hpp"
|
|
#include "plane.hpp"
|
|
#include "aabb.hpp"
|
|
|
|
#include <array>
|
|
|
|
#include <cstddef>
|
|
|
|
namespace util::geom {
|
|
/// a viewing frustrum comprised of 4 axis planes, a near plane, and a far
|
|
/// plane. it may describe something other than a perspective projection
|
|
/// (eg, an orthographic projection)
|
|
template <typename ValueT>
|
|
struct frustum {
|
|
explicit frustum (const matrix<4,4,ValueT>&);
|
|
|
|
std::array<plane<3,ValueT>, 6> planes;
|
|
};
|
|
|
|
using frustum3f = frustum<float>;
|
|
|
|
|
|
/// tests whether a frustum and an aabb overlap
|
|
///
|
|
/// XXX: there may be occasional false positives.
|
|
template <size_t S, typename T>
|
|
bool
|
|
intersects (const frustum<T> &f, const aabb<S,T> &b)
|
|
{
|
|
for (const auto &p: f.planes) {
|
|
const auto n = normal (p);
|
|
const auto positive = n > 0;
|
|
|
|
const auto lo = select (positive, b.lo, b.hi);
|
|
const auto hi = select (positive, b.hi, b.lo);
|
|
|
|
if (dot (n, lo) + p.coefficients[S] > 0)
|
|
return false; // OUTSIDE
|
|
|
|
if (dot (n, hi) + p.coefficients[S] >= 0)
|
|
return true; //INTERSECT
|
|
}
|
|
|
|
// INSIDE
|
|
return true;
|
|
}
|
|
};
|
|
|
|
#endif
|