Steve Pham
106 lines
3.1 KiB
C++
106 lines
3.1 KiB
C++
/*
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* Copyright (c) Contributors to the Open 3D Engine Project
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*
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* SPDX-License-Identifier: Apache-2.0 OR MIT
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*
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*/
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// include required headers
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#include "BoundingSphere.h"
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#include "AABB.h"
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namespace MCore
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{
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// encapsulate a point in the sphere
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void BoundingSphere::Encapsulate(const AZ::Vector3& v)
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{
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// calculate the squared distance from the center to the point
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const AZ::Vector3 diff = v - mCenter;
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const float dist = diff.Dot(diff);
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// if the current sphere doesn't contain the point, grow the sphere so that it contains the point
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if (dist > mRadiusSq)
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{
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const AZ::Vector3 diff2 = diff.GetNormalized() * mRadius;
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const AZ::Vector3 delta = 0.5f * (diff - diff2);
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mCenter += delta;
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// TODO: KB- Was a 'safe' function, is there an AZ equivalent?
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float length = delta.GetLengthSq();
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if (length >= FLT_EPSILON)
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{
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mRadius += sqrtf(length);
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}
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else
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{
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mRadius = 0.0f;
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}
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mRadiusSq = mRadius * mRadius;
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}
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}
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// check if the sphere intersects with a given AABB
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bool BoundingSphere::Intersects(const AABB& b) const
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{
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float distance = 0.0f;
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for (uint32 t = 0; t < 3; ++t)
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{
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const AZ::Vector3& minVec = b.GetMin();
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if (mCenter.GetElement(t) < minVec.GetElement(t))
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{
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distance += (mCenter.GetElement(t) - minVec.GetElement(t)) * (mCenter.GetElement(t) - minVec.GetElement(t));
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if (distance > mRadiusSq)
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{
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return false;
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}
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}
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else
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{
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const AZ::Vector3& maxVec = b.GetMax();
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if (mCenter.GetElement(t) > maxVec.GetElement(t))
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{
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distance += (mCenter.GetElement(t) - maxVec.GetElement(t)) * (mCenter.GetElement(t) - maxVec.GetElement(t));
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if (distance > mRadiusSq)
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{
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return false;
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}
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}
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}
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}
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return true;
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}
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// check if the sphere completely contains a given AABB
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bool BoundingSphere::Contains(const AABB& b) const
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{
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float distance = 0.0f;
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for (uint32 t = 0; t < 3; ++t)
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{
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const AZ::Vector3& maxVec = b.GetMax();
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if (mCenter.GetElement(t) < maxVec.GetElement(t))
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{
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distance += (mCenter.GetElement(t) - maxVec.GetElement(t)) * (mCenter.GetElement(t) - maxVec.GetElement(t));
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}
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else
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{
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const AZ::Vector3& minVec = b.GetMin();
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if (mCenter.GetElement(t) > minVec.GetElement(t))
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{
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distance += (mCenter.GetElement(t) - minVec.GetElement(t)) * (mCenter.GetElement(t) - minVec.GetElement(t));
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}
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}
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if (distance > mRadiusSq)
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{
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return false;
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}
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}
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return true;
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}
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} // namespace MCore
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