reactphysics3d/src/collision/narrowphase/SphereVsSphereAlgorithm.cpp
2017-12-04 22:14:52 +01:00

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4.8 KiB
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/********************************************************************************
* ReactPhysics3D physics library, http://www.reactphysics3d.com *
* Copyright (c) 2010-2016 Daniel Chappuis *
*********************************************************************************
* *
* This software is provided 'as-is', without any express or implied warranty. *
* In no event will the authors be held liable for any damages arising from the *
* use of this software. *
* *
* Permission is granted to anyone to use this software for any purpose, *
* including commercial applications, and to alter it and redistribute it *
* freely, subject to the following restrictions: *
* *
* 1. The origin of this software must not be misrepresented; you must not claim *
* that you wrote the original software. If you use this software in a *
* product, an acknowledgment in the product documentation would be *
* appreciated but is not required. *
* *
* 2. Altered source versions must be plainly marked as such, and must not be *
* misrepresented as being the original software. *
* *
* 3. This notice may not be removed or altered from any source distribution. *
* *
********************************************************************************/
// Libraries
#include "SphereVsSphereAlgorithm.h"
#include "collision/shapes/SphereShape.h"
// We want to use the ReactPhysics3D namespace
using namespace reactphysics3d;
bool SphereVsSphereAlgorithm::testCollision(NarrowPhaseInfo* narrowPhaseInfo, bool reportContacts,
Allocator& memoryAllocator) {
assert(narrowPhaseInfo->collisionShape1->getType() == CollisionShapeType::SPHERE);
assert(narrowPhaseInfo->collisionShape2->getType() == CollisionShapeType::SPHERE);
// Get the sphere collision shapes
const SphereShape* sphereShape1 = static_cast<const SphereShape*>(narrowPhaseInfo->collisionShape1);
const SphereShape* sphereShape2 = static_cast<const SphereShape*>(narrowPhaseInfo->collisionShape2);
// Get the local-space to world-space transforms
const Transform& transform1 = narrowPhaseInfo->shape1ToWorldTransform;
const Transform& transform2 = narrowPhaseInfo->shape2ToWorldTransform;
// Compute the distance between the centers
Vector3 vectorBetweenCenters = transform2.getPosition() - transform1.getPosition();
decimal squaredDistanceBetweenCenters = vectorBetweenCenters.lengthSquare();
// Compute the sum of the radius
decimal sumRadius = sphereShape1->getRadius() + sphereShape2->getRadius();
// If the sphere collision shapes intersect
if (squaredDistanceBetweenCenters < sumRadius * sumRadius) {
if (reportContacts) {
Vector3 centerSphere2InBody1LocalSpace = transform1.getInverse() * transform2.getPosition();
Vector3 centerSphere1InBody2LocalSpace = transform2.getInverse() * transform1.getPosition();
decimal penetrationDepth = sumRadius - std::sqrt(squaredDistanceBetweenCenters);
Vector3 intersectionOnBody1;
Vector3 intersectionOnBody2;
Vector3 normal;
// If the two sphere centers are not at the same position
if (squaredDistanceBetweenCenters > MACHINE_EPSILON) {
intersectionOnBody1 = sphereShape1->getRadius() * centerSphere2InBody1LocalSpace.getUnit();
intersectionOnBody2 = sphereShape2->getRadius() * centerSphere1InBody2LocalSpace.getUnit();
normal = vectorBetweenCenters.getUnit();
}
else { // If the sphere centers are at the same position (degenerate case)
// Take any contact normal direction
normal.setAllValues(0, 1, 0);
intersectionOnBody1 = sphereShape1->getRadius() * (transform1.getInverse().getOrientation() * normal);
intersectionOnBody2 = sphereShape2->getRadius() * (transform2.getInverse().getOrientation() * normal);
}
// Create the contact info object
narrowPhaseInfo->addContactPoint(normal, penetrationDepth, intersectionOnBody1, intersectionOnBody2);
}
return true;
}
return false;
}