vladislavbelov
ffc4a56b9f
Fixes #6846 Differential Revision: https://code.wildfiregames.com/D5185 This was SVN commit r27965.
98 lines
3.0 KiB
C++
98 lines
3.0 KiB
C++
/* Copyright (C) 2019 Wildfire Games.
|
|
* This file is part of 0 A.D.
|
|
*
|
|
* 0 A.D. is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 0 A.D. is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "precompiled.h"
|
|
|
|
#include "BoundingBoxOriented.h"
|
|
#include "maths/BoundingBoxAligned.h"
|
|
|
|
#include <float.h>
|
|
|
|
const CBoundingBoxOriented CBoundingBoxOriented::EMPTY = CBoundingBoxOriented();
|
|
|
|
CBoundingBoxOriented::CBoundingBoxOriented(const CBoundingBoxAligned& bound)
|
|
{
|
|
if (bound.IsEmpty())
|
|
{
|
|
SetEmpty();
|
|
}
|
|
else
|
|
{
|
|
bound.GetCenter(m_Center);
|
|
|
|
// the axes of an AABB are the world-space axes
|
|
m_Basis[0].X = 1.f; m_Basis[0].Y = 0.f; m_Basis[0].Z = 0.f;
|
|
m_Basis[1].X = 0.f; m_Basis[1].Y = 1.f; m_Basis[1].Z = 0.f;
|
|
m_Basis[2].X = 0.f; m_Basis[2].Y = 0.f; m_Basis[2].Z = 1.f;
|
|
|
|
// element-wise division by two to get half sizes (remember, [1] and [0] are the max and min coord points)
|
|
m_HalfSizes = (bound[1] - bound[0]) * 0.5f;
|
|
}
|
|
}
|
|
|
|
bool CBoundingBoxOriented::RayIntersect(const CVector3D& origin, const CVector3D& dir, float& tMin_out, float& tMax_out) const
|
|
{
|
|
// See Real-Time Rendering, Third Edition, p. 743
|
|
float tMin = -FLT_MAX;
|
|
float tMax = FLT_MAX;
|
|
|
|
CVector3D p = m_Center - origin;
|
|
|
|
for (int i = 0; i < 3; ++i)
|
|
{
|
|
// test the ray for intersections with the slab whose normal vector is m_Basis[i]
|
|
float e = m_Basis[i].Dot(p); // distance between the ray origin and the box center projected onto the slab normal
|
|
float f = m_Basis[i].Dot(dir); // cosine of the angle between the slab normal and the ray direction
|
|
|
|
if(fabsf(f) > 1e-10f)
|
|
{
|
|
// Determine the distances t1 and t2 from the origin of the ray to the points where it intersects
|
|
// the slab. See docs/ray_intersect.pdf for why/how this works.
|
|
float invF = 1.f/f;
|
|
float t1 = (e + m_HalfSizes[i]) * invF;
|
|
float t2 = (e - m_HalfSizes[i]) * invF;
|
|
|
|
// make sure t1 <= t2, swap if necessary
|
|
if (t1 > t2)
|
|
{
|
|
float tmp = t1;
|
|
t1 = t2;
|
|
t2 = tmp;
|
|
}
|
|
|
|
// update the overall tMin and tMax if necessary
|
|
if (t1 > tMin) tMin = t1;
|
|
if (t2 < tMax) tMax = t2;
|
|
|
|
// try to break out of the loop as fast as possible by checking for some conditions
|
|
if (tMin > tMax) return false; // ray misses the box
|
|
if (tMax < 0) return false; // box is behind the ray origin
|
|
}
|
|
else
|
|
{
|
|
// the ray is parallel to the slab currently being tested, or is as close to parallel
|
|
// as makes no difference; return false if the ray is outside of the slab.
|
|
if (e > m_HalfSizes[i] || -e > m_HalfSizes[i])
|
|
return false;
|
|
}
|
|
}
|
|
|
|
tMin_out = tMin;
|
|
tMax_out = tMax;
|
|
return true;
|
|
}
|