Commit 1be1afde authored by Julian Schakib's avatar Julian Schakib
Browse files

frustum object

parent ed32d571
#pragma once
#include <typed-geometry/feature/assert.hh>
#include <typed-geometry/functions/swizzling/swizzling-basic.hh>
#include <typed-geometry/functions/vector/dot.hh>
#include <typed-geometry/functions/vector/length.hh>
#include <typed-geometry/functions/vector/normalize.hh>
#include <typed-geometry/types/scalars/default.hh>
#include "../pos.hh"
#include "../vec.hh"
#include "plane.hh"
namespace tg
{
template <class ScalarT>
struct frustum;
// Common frustum types
using ffrustum = frustum<f32>;
using dfrustum = frustum<f64>;
// ======== IMPLEMENTATION ========
template <class ScalarT>
struct frustum
{
// frustum represented by 6 planes
array<tg::plane<3, ScalarT>, 6> planes;
constexpr frustum() = default;
explicit constexpr frustum(array<tg::plane<3, ScalarT>, 6> const& planes) : planes(planes)
{ /* TG_CONTRACT(..); */
}
// extract frustum from a view-projection-matrix (proj * view)
explicit constexpr frustum(mat<4, 4, ScalarT> const& m)
{
// computing planes in order: left, right, bottom, top, near, far
for (auto i = 0u; i < 3; ++i)
for (auto j = 0u; j < 2; ++j)
{
// plane parameters from matrix (see http://www8.cs.umu.se/kurser/5DV051/HT12/lab/plane_extraction.pdf)
vec4 abcd;
for (auto k = 0; k < 4; ++k)
abcd[k] = j == 0 ? m[k][3] + m[k][i] : m[k][3] - m[k][i];
auto n = vec3(abcd);
auto l = length(n);
planes[2 * i + j] = plane3(dir3(n / l), -abcd.w / l);
}
}
[[nodiscard]] bool operator==(frustum const& rhs) const
{
for (auto i = 0u; i < planes.size(); ++i)
{
if (planes[i] != rhs.planes[i])
return false;
}
return true;
}
[[nodiscard]] bool operator!=(frustum const& rhs) const { return !operator==(rhs); }
};
template <class I, int D, class ScalarT, class TraitsT>
constexpr void introspect(I&& i, frustum<ScalarT>& v)
{
i(v.planes, "planes");
}
} // namespace tg
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