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157c6af18e
Avoid cases of filenames Update years in terms and other legal(ish) documents Don't update years in license headers, since change is not meaningful Will add linter rule in seperate commit Happy recompiling everyone! Original Patch By: Nescio Comment By: Gallaecio Differential Revision: D2620 This was SVN commit r27786.
97 lines
3 KiB
C++
97 lines
3 KiB
C++
/* Copyright (C) 2019 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "precompiled.h"
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#include "BoundingBoxOriented.h"
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#include "maths/BoundingBoxAligned.h"
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#include <float.h>
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const CBoundingBoxOriented CBoundingBoxOriented::EMPTY = CBoundingBoxOriented();
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CBoundingBoxOriented::CBoundingBoxOriented(const CBoundingBoxAligned& bound)
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{
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if (bound.IsEmpty())
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{
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SetEmpty();
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}
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else
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{
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bound.GetCenter(m_Center);
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// the axes of an AABB are the world-space axes
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m_Basis[0].X = 1.f; m_Basis[0].Y = 0.f; m_Basis[0].Z = 0.f;
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m_Basis[1].X = 0.f; m_Basis[1].Y = 1.f; m_Basis[1].Z = 0.f;
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m_Basis[2].X = 0.f; m_Basis[2].Y = 0.f; m_Basis[2].Z = 1.f;
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// element-wise division by two to get half sizes (remember, [1] and [0] are the max and min coord points)
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m_HalfSizes = (bound[1] - bound[0]) * 0.5f;
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}
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}
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bool CBoundingBoxOriented::RayIntersect(const CVector3D& origin, const CVector3D& dir, float& tMin_out, float& tMax_out) const
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{
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// See Real-Time Rendering, Third Edition, p. 743
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float tMin = -FLT_MAX;
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float tMax = FLT_MAX;
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CVector3D p = m_Center - origin;
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for (int i = 0; i < 3; ++i)
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{
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// test the ray for intersections with the slab whose normal vector is m_Basis[i]
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float e = m_Basis[i].Dot(p); // distance between the ray origin and the box center projected onto the slab normal
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float f = m_Basis[i].Dot(dir); // cosine of the angle between the slab normal and the ray direction
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if(fabsf(f) > 1e-10f)
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{
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// Determine the distances t1 and t2 from the origin of the ray to the points where it intersects
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// the slab. See docs/ray_intersect.pdf for why/how this works.
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float invF = 1.f/f;
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float t1 = (e + m_HalfSizes[i]) * invF;
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float t2 = (e - m_HalfSizes[i]) * invF;
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// make sure t1 <= t2, swap if necessary
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if (t1 > t2)
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{
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float tmp = t1;
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t1 = t2;
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t2 = tmp;
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}
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// update the overall tMin and tMax if necessary
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if (t1 > tMin) tMin = t1;
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if (t2 < tMax) tMax = t2;
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// try to break out of the loop as fast as possible by checking for some conditions
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if (tMin > tMax) return false; // ray misses the box
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if (tMax < 0) return false; // box is behind the ray origin
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}
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else
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{
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// the ray is parallel to the slab currently being tested, or is as close to parallel
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// as makes no difference; return false if the ray is outside of the slab.
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if (e > m_HalfSizes[i] || -e > m_HalfSizes[i])
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return false;
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}
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}
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tMin_out = tMin;
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tMax_out = tMax;
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return true;
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}
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