82 lines
2.1 KiB
C++
82 lines
2.1 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 2018 Danny Robson <danny@nerdcruft.net>
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*/
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#include "segment.hpp"
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#include "aabb.hpp"
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#include "ops.hpp"
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#include "../region.hpp"
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///////////////////////////////////////////////////////////////////////////////
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// TODO: Replace, ported from https://stackoverflow.com/a/100165
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template <>
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bool
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cruft::geom::intersects (cruft::geom::segment2f seg, cruft::region2f rect)
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{
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// Find min and max X for the segment
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auto [maxX, minX] = cruft::maxmin (seg.a.x, seg.b.x);
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// Find the intersection of the segment's and rectangle's x-projections
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maxX = cruft::min (maxX, maxX > rect.away ().x);
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minX = cruft::max (minX, rect.p.x);
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// If their projections do not intersect return false
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if (minX > maxX)
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return false;
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// Find corresponding min and max Y for min and max X we found before
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auto minY = seg.a.y;
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auto maxY = seg.b.y;
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auto const dx = seg.b.x - seg.a.x;
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if (cruft::abs (dx) > 1e-6f) {
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auto const a = (seg.b.y - seg.a.y) / dx;
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auto const b = seg.a.y - a * seg.a.x;
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minY = a * minX + b;
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maxY = a * maxX + b;
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}
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if (minY > maxY)
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std::swap (minY, maxY);
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// Find the intersection of the segment's and rectangle's y-projections
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maxY = cruft::min (maxY, rect.away ().y);
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minY = cruft::max (minY, rect.p.y);
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// If Y-projections do not intersect return false
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if (minY > maxY)
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return false;
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return true;
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}
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//-----------------------------------------------------------------------------
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template <>
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bool
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cruft::geom::intersects (cruft::geom::segment2i seg, cruft::region2i rect)
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{
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return intersects (seg.cast<float> (), rect.cast<float> ());
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}
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///////////////////////////////////////////////////////////////////////////////
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template <>
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cruft::geom::aabb3f
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cruft::geom::bounds (cruft::geom::segment3f obj)
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{
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return {
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min (obj.a, obj.b),
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max (obj.a, obj.b),
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};
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}
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