98 lines
4.1 KiB
C++
98 lines
4.1 KiB
C++
/********************************************************************************
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* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/ *
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* Copyright (c) 2010-2013 Daniel Chappuis *
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*********************************************************************************
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* *
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* This software is provided 'as-is', without any express or implied warranty. *
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* In no event will the authors be held liable for any damages arising from the *
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* use of this software. *
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* *
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* Permission is granted to anyone to use this software for any purpose, *
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* including commercial applications, and to alter it and redistribute it *
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* freely, subject to the following restrictions: *
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* *
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* 1. The origin of this software must not be misrepresented; you must not claim *
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* that you wrote the original software. If you use this software in a *
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* product, an acknowledgment in the product documentation would be *
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* appreciated but is not required. *
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* *
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* 2. Altered source versions must be plainly marked as such, and must not be *
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* misrepresented as being the original software. *
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* *
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* 3. This notice may not be removed or altered from any source distribution. *
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* *
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********************************************************************************/
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// Libraries
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#include "SphereShape.h"
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#include "collision/ProxyShape.h"
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#include "configuration.h"
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#include <cassert>
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using namespace reactphysics3d;
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// Constructor
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SphereShape::SphereShape(decimal radius) : CollisionShape(SPHERE, radius), mRadius(radius) {
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assert(radius > decimal(0.0));
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}
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// Private copy-constructor
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SphereShape::SphereShape(const SphereShape& shape)
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: CollisionShape(shape), mRadius(shape.mRadius) {
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}
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// Destructor
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SphereShape::~SphereShape() {
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}
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// Raycast method with feedback information
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bool SphereShape::raycast(const Ray& ray, RaycastInfo& raycastInfo, ProxyShape* proxyShape) const {
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// We perform the intersection test in world-space
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const Vector3 sphereCenter = proxyShape->getLocalToWorldTransform().getPosition();
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const Vector3 m = ray.point1 - sphereCenter;
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decimal c = m.dot(m) - mRadius * mRadius;
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// If the origin of the ray is inside the sphere, we return no intersection
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if (c < decimal(0.0)) return false;
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const Vector3 rayDirection = ray.point2 - ray.point1;
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decimal b = m.dot(rayDirection);
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// If the origin of the ray is outside the sphere and the ray
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// is pointing away from the sphere, there is no intersection
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if (b > decimal(0.0)) return false;
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decimal raySquareLength = rayDirection.lengthSquare();
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// Compute the discriminant of the quadratic equation
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decimal discriminant = b * b - raySquareLength * c;
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// If the discriminant is negative or the ray length is very small, there is no intersection
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if (discriminant < decimal(0.0) || raySquareLength < MACHINE_EPSILON) return false;
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// Compute the solution "t" closest to the origin
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decimal t = -b - std::sqrt(discriminant);
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assert(t >= decimal(0.0));
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// If the hit point is withing the segment ray fraction
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if (t < ray.maxFraction * raySquareLength) {
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// Compute the intersection information
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t /= raySquareLength;
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raycastInfo.body = proxyShape->getBody();
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raycastInfo.proxyShape = proxyShape;
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raycastInfo.hitFraction = t;
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raycastInfo.worldPoint = ray.point1 + t * rayDirection;
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raycastInfo.worldNormal = (raycastInfo.worldPoint - sphereCenter).getUnit();
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return true;
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}
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return false;
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}
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