Initial commit

Gems/EMotionFX/Code/MCore/Source/BoundingSphere.cpp

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+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+// include required headers
+#include "BoundingSphere.h"
+#include "AABB.h"
+
+
+namespace MCore
+{
+    // encapsulate a point in the sphere
+    void BoundingSphere::Encapsulate(const AZ::Vector3& v)
+    {
+        // calculate the squared distance from the center to the point
+        const AZ::Vector3 diff = v - mCenter;
+        const float dist = diff.Dot(diff);
+
+        // if the current sphere doesn't contain the point, grow the sphere so that it contains the point
+        if (dist > mRadiusSq)
+        {
+            const AZ::Vector3 diff2 = diff.GetNormalized() * mRadius;
+            const AZ::Vector3 delta = 0.5f * (diff - diff2);
+            mCenter             += delta;
+            // TODO: KB- Was a 'safe' function, is there an AZ equivalent?
+            float length = delta.GetLengthSq();
+            if (length >= FLT_EPSILON)
+            {
+                mRadius += sqrtf(length);
+            }
+            else
+            {
+                mRadius = 0.0f;
+            }
+            mRadiusSq = mRadius * mRadius;
+        }
+    }
+
+
+    // check if the sphere intersects with a given AABB
+    bool BoundingSphere::Intersects(const AABB& b) const
+    {
+        float distance = 0.0f;
+
+        for (uint32 t = 0; t < 3; ++t)
+        {
+            const AZ::Vector3& minVec = b.GetMin();
+            if (mCenter.GetElement(t) < minVec.GetElement(t))
+            {
+                distance += (mCenter.GetElement(t) - minVec.GetElement(t)) * (mCenter.GetElement(t) - minVec.GetElement(t));
+                if (distance > mRadiusSq)
+                {
+                    return false;
+                }
+            }
+            else
+            {
+                const AZ::Vector3& maxVec = b.GetMax();
+                if (mCenter.GetElement(t) > maxVec.GetElement(t))
+                {
+                    distance += (mCenter.GetElement(t) - maxVec.GetElement(t)) * (mCenter.GetElement(t) - maxVec.GetElement(t));
+                    if (distance > mRadiusSq)
+                    {
+                        return false;
+                    }
+                }
+            }
+        }
+
+        return true;
+    }
+
+
+    // check if the sphere completely contains a given AABB
+    bool BoundingSphere::Contains(const AABB& b) const
+    {
+        float distance = 0.0f;
+        for (uint32 t = 0; t < 3; ++t)
+        {
+            const AZ::Vector3& maxVec = b.GetMax();
+            if (mCenter.GetElement(t) < maxVec.GetElement(t))
+            {
+                distance += (mCenter.GetElement(t) - maxVec.GetElement(t)) * (mCenter.GetElement(t) - maxVec.GetElement(t));
+            }
+            else
+            {
+                const AZ::Vector3& minVec = b.GetMin();
+                if (mCenter.GetElement(t) > minVec.GetElement(t))
+                {
+                    distance += (mCenter.GetElement(t) - minVec.GetElement(t)) * (mCenter.GetElement(t) - minVec.GetElement(t));
+                }
+            }
+
+            if (distance > mRadiusSq)
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}   // namespace MCore