145 lines
4.3 KiB
C++
145 lines
4.3 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
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*/
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#include "ellipse.hpp"
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#include "ops.hpp"
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#include "aabb.hpp"
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#include "ray.hpp"
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#include "sphere.hpp"
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#include <cruft/util/quaternion.hpp>
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#include "../point.hpp"
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#include "../matrix.hpp"
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#include "../coord/iostream.hpp"
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using cruft::geom::ellipse;
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///////////////////////////////////////////////////////////////////////////////
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template <>
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bool
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cruft::geom::intersects (ellipse3f e, cruft::point3f p)
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{
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auto transform = cruft::quaternionf::from_to (e.up, {0,1,0}).as_matrix () *
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cruft::translation (0-e.origin);
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return all (abs (transform * p) <= e.radius);
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//auto mag = (p - e.origin) * (p - e.origin) / (e.radius * e.radius);
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//return std::accumulate (mag.begin (), mag.end (), 0) <= 1;
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}
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///////////////////////////////////////////////////////////////////////////////
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// query a ray-ellipse distance by transforming spaces such that the ellipse is
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// a sphere
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template <>
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float
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cruft::geom::distance (ray3f r, ellipse3f e)
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{
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// find a transform that puts the ellipse at origin and scales it to a
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// unit sphere.
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auto const from_scaled = cruft::translation (e.origin.template as<vector> ()) *
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cruft::quaternionf::from_to ({0,1,0}, e.up) *
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cruft::scale (e.radius);
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auto const to_scaled = inverse (from_scaled);
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// transform the ray into this new space and query against a unit sphere
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auto const scaled_r = to_scaled * r;
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auto const scaled_d = distance (scaled_r, sphere3f {0, 1.f});
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auto const scaled_p = scaled_r.at (scaled_d);
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// transform the result back into the original space
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return distance (r.origin, from_scaled * scaled_p);
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}
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///////////////////////////////////////////////////////////////////////////////
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template <>
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cruft::point3f
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cruft::geom::project (cruft::geom::ray3f lhs,
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cruft::geom::ellipse3f rhs)
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{
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return lhs.origin + lhs.direction * distance (lhs, rhs);
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}
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///////////////////////////////////////////////////////////////////////////////
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cruft::geom::ellipse3f
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cruft::geom::cover (cruft::view<const point3f*> src)
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{
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// find our major axis points and vector
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const auto [a,b] = furthest (src);
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auto const diff = b - a;
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auto const dir = normalised (diff);
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// find a transform such that we recentre about the origin
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auto const transform = quaternionf::from_to (dir, cruft::vector3f{1,0,0}).as_matrix () *
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translation (0 -a -diff*0.5f);
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// find the maximum absolute value in each axis
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cruft::point3f hi {0};
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for (auto const& p: src)
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hi = max (abs (transform * p), hi);
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return ellipse3f {
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.origin = a + diff * 0.5f,
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.radius = hi.as<vector> (),
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.up = rotate ({0,1,0}, cruft::quaternionf::from_to ({1,0,0}, dir))
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};
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};
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///////////////////////////////////////////////////////////////////////////////
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template <size_t S, typename T>
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static cruft::geom::aabb<S,T>
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bounds (ellipse<S,T> e)
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{
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return {
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e.origin - e.radius,
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e.origin + e.radius
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};
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}
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//-----------------------------------------------------------------------------
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template <size_t S, typename T, template <size_t,typename> class K>
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cruft::geom::aabb<S,T>
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cruft::geom::bounds (K<S,T> k)
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{
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return ::bounds (k);
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}
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///////////////////////////////////////////////////////////////////////////////
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template <size_t S, typename T>
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std::ostream&
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cruft::geom::operator<< (std::ostream &os, ellipse<S,T> val)
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{
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return os << "{ origin: " << val.origin
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<< ", radius: " << val.radius
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<< ", up: " << val.up
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<< " }";
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}
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///////////////////////////////////////////////////////////////////////////////
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#define INSTANTIATE_S_T(S,T) \
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template cruft::geom::aabb<S,T> cruft::geom::bounds (ellipse<S,T>); \
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template std::ostream& cruft::geom::operator<< (std::ostream&, ellipse<S,T>);
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//template cruft::point<S,T> cruft::geom::project(ray<S,T>, ellipse<S,T>);
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//template bool cruft::geom::intersects (ellipse<S,T>, cruft::point<S,T>);
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INSTANTIATE_S_T(2,float)
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INSTANTIATE_S_T(3,float)
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