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Refactor CBoundingSphere and add tests

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Reviewed By: wraitii
Comments By: smiley, Stan
Differential Revision: https://code.wildfiregames.com/D1576
This was SVN commit r22143.
This commit is contained in:
Vladislav Belov 2019-03-25 21:17:43 +00:00
parent 8ee8faf54b
commit cb83d494e0
3 changed files with 144 additions and 36 deletions
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46
source/maths/BoundingSphere.cpp Normal file
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@ -0,0 +1,46 @@
/* 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 "maths/BoundingBoxAligned.h"
#include "maths/BoundingSphere.h"
CBoundingSphere CBoundingSphere::FromSweptBox(const CBoundingBoxAligned& bbox)
{
float maxX = std::max(fabsf(bbox[0].X), fabsf(bbox[1].X));
float maxY = std::max(fabsf(bbox[0].Y), fabsf(bbox[1].Y));
float maxZ = std::max(fabsf(bbox[0].Z), fabsf(bbox[1].Z));
float radius = sqrtf(maxX*maxX + maxY*maxY + maxZ*maxZ);
return CBoundingSphere(CVector3D(0.f, 0.f, 0.f), radius);
}
bool CBoundingSphere::RayIntersect(const CVector3D& origin, const CVector3D& dir) const
{
// Vector v from the origin of the ray to the center of the sphere
CVector3D v = m_Center - origin;
// Length of the projection of v onto the direction vector of the ray
const float pcLen = dir.Dot(v);
if (pcLen > 0.0f)
{
// Get the shortest distance from the center of the sphere to the ray
v = dir * pcLen - v;
}
return v.LengthSquared() <= m_Radius * m_Radius;
}

54
source/maths/BoundingSphere.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2014 Wildfire Games.
/* 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
@ -18,35 +18,18 @@
#ifndef INCLUDED_BOUNDINGSPHERE
#define INCLUDED_BOUNDINGSPHERE
#include "maths/BoundingBoxAligned.h"
#include "maths/Vector3D.h"
class BoundingBoxAligned;
class CBoundingSphere
{
private:
CVector3D m_Center;
float m_Radius;
public:
CBoundingSphere() : m_Radius(0) { }
CBoundingSphere() : m_Radius(0.0f) { }
CBoundingSphere(const CVector3D& center, float radius) : m_Center(center), m_Radius(radius) { }
/**
* Construct a bounding sphere that encompasses a bounding box
* swept through all possible rotations around the origin.
*/
static CBoundingSphere FromSweptBox(const CBoundingBoxAligned& bbox)
{
float maxX = std::max(fabsf(bbox[0].X), fabsf(bbox[1].X));
float maxY = std::max(fabsf(bbox[0].Y), fabsf(bbox[1].Y));
float maxZ = std::max(fabsf(bbox[0].Z), fabsf(bbox[1].Z));
float radius = sqrtf(maxX*maxX + maxY*maxY + maxZ*maxZ);
return CBoundingSphere(CVector3D(0.f, 0.f, 0.f), radius);
}
const CVector3D& GetCenter()
const CVector3D& GetCenter() const
{
return m_Center;
}
@ -57,21 +40,20 @@ public:
}
/**
* Check if the ray, defined by an origin point and a direction unit vector
* interesects with the sphere
* Construct a bounding sphere that encompasses a bounding box
* swept through all possible rotations around the origin.
*/
bool RayIntersect(const CVector3D& origin, const CVector3D& dir) const
{
CVector3D v = m_Center - origin; // Vector v from the origin of the ray to the center of the sphere
float pcLen = dir.Dot(v); // Length of the projection of v onto the direction vector of the ray
if(pcLen <= 0)
return false; // Sphere behind the ray
// Get the shortest distance from the center of the sphere to the ray
v = (dir * pcLen) - v;
if (v.LengthSquared() > m_Radius * m_Radius)
return false; // Distance to sphere center more than radius
return true;
}
static CBoundingSphere FromSweptBox(const CBoundingBoxAligned& bbox);
/**
* Check if the ray, defined by an origin point and a direction unit vector
* interesects with the sphere. The direction should be normalized.
*/
bool RayIntersect(const CVector3D& origin, const CVector3D& dir) const;
private:
CVector3D m_Center;
float m_Radius;
};
#endif // INCLUDED_BOUNDINGSPHERE

80
source/maths/tests/test_BoundingSphere.h Normal file
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/* 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 "lib/self_test.h"
#include "maths/BoundingBoxAligned.h"
#include "maths/BoundingSphere.h"
#include <cmath>
class TestBoundingSphere : public CxxTest::TestSuite
{
public:
void test_basic()
{
CBoundingBoxAligned indentityAABB(CVector3D(-1.0f, -1.0f, -1.0f), CVector3D(1.0f, 1.0f, 1.0f));
CBoundingSphere bs1 = CBoundingSphere::FromSweptBox(indentityAABB);
// The radius should be equal to the length of diagonal in an identity cube.
TS_ASSERT_DELTA(bs1.GetRadius(), sqrtf(3.0f), 1e-5);
TS_ASSERT_EQUALS(bs1.GetCenter(), CVector3D(0.0f, 0.0f, 0.0f));
CBoundingBoxAligned translatedAABB;
CVector3D translate(1.0f, 2.0f, 3.0f);
indentityAABB.Translate(translate, translatedAABB);
CBoundingSphere bs2 = CBoundingSphere::FromSweptBox(translatedAABB);
CVector3D farVertex = translate + CVector3D(1.0f, 1.0f, 1.0f);
TS_ASSERT_DELTA(bs2.GetRadius(), farVertex.Length(), 1e-5);
TS_ASSERT_EQUALS(bs2.GetCenter(), CVector3D(0.0f, 0.0f, 0.0f));
}
void check_intersections(const CVector3D& pivot)
{
// Axis aligned rays for different axis.
CBoundingSphere bs1(pivot, 1.0f);
for (size_t i = 0; i < 3; ++i)
{
CVector3D origin = pivot, direction;
origin[i] += 2.0f;
direction[i] = 1.0f;
TS_ASSERT_EQUALS(bs1.RayIntersect(origin, -direction), true);
TS_ASSERT_EQUALS(bs1.RayIntersect(origin, direction), false);
}
// Rays inside bounding spheres.
CBoundingSphere bs2(pivot, 10.0f);
TS_ASSERT_EQUALS(bs2.RayIntersect(pivot + CVector3D(0.0f, 1.0f, 0.0f), CVector3D(0.0f, 1.0f, 0.0f)), true);
TS_ASSERT_EQUALS(bs2.RayIntersect(pivot - CVector3D(0.0f, 1.0f, 0.0f), CVector3D(0.0f, 1.0f, 0.0f)), true);
CBoundingSphere bs3(pivot, 2.0f);
TS_ASSERT_EQUALS(bs3.RayIntersect(pivot + CVector3D(-4.0f, -2.0f, -4.0f), CVector3D(1.0f, 1.0f, 1.0f).Normalized()), true);
TS_ASSERT_EQUALS(bs3.RayIntersect(pivot + CVector3D(-4.0f, -1.0f, -4.0f), CVector3D(1.0f, 1.0f, 1.0f).Normalized()), false);
}
void test_intersections()
{
// Initial positions of bounding spheres.
CVector3D pivots[] = {
CVector3D(0.0f, 0.0f, 0.0f),
CVector3D(1.0f, 2.0f, 3.0f),
CVector3D(-10.0f, 0.5f, 3.0f)
};
for (const CVector3D& pivot : pivots)
check_intersections(pivot);
}
};