116 lines
3.6 KiB
C++
116 lines
3.6 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015-2017 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 "point.hpp"
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#include "../matrix.hpp"
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using util::geom::ellipse;
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///////////////////////////////////////////////////////////////////////////////
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template <size_t S, typename T>
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static bool
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intersects (ellipse<S,T> e, util::point<S,T> p)
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{
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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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template <size_t S, typename T, template <size_t,typename> class A, template <size_t,typename> class B>
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bool
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util::geom::intersects (A<S,T> a, B<S,T> b)
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{
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return ::intersects (a, b);
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}
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//-----------------------------------------------------------------------------
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///////////////////////////////////////////////////////////////////////////////
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template <size_t DimensionV, typename ValueT>
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util::point<DimensionV,ValueT>
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util::geom::project (util::geom::ray<DimensionV, ValueT> lhs,
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util::geom::ellipse<DimensionV, ValueT> 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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// query a ray-ellipse distance by transforming spaces such that the ellipse is
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// a sphere
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template <size_t DimensionV, typename ValueT>
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ValueT
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util::geom::distance (ray<DimensionV,ValueT> r, ellipse<DimensionV,ValueT> 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 = util::translation (e.origin.template as<vector> ()) *
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util::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, sphere<DimensionV,ValueT> {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.homog ()).template redim<DimensionV> ());
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}
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///////////////////////////////////////////////////////////////////////////////
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template <size_t S, typename T>
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static util::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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util::geom::aabb<S,T>
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util::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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#define INSTANTIATE_S_T(S,T) \
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template bool util::geom::intersects (ellipse<S,T>, util::point<S,T>); \
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template util::point<S,T> util::geom::project(ray<S,T>, ellipse<S,T>); \
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template util::geom::aabb<S,T> util::geom::bounds (ellipse<S,T>);
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INSTANTIATE_S_T(2,float)
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INSTANTIATE_S_T(3,float)
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