GEEKING

App/util/Region2.cpp

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+/* Copyright 2003-2005 ROBLOX Corporation, All Rights Reserved */
+#include "stdafx.h"
+
+#include "Util/Region2.h"
+#include "Util/quadedge.h"
+
+namespace RBX {
+
+
+// static
+float Region2::getRelativeError(const Vector2& pos2d, const WeightedPoint& owner)
+{
+	float distanceSquared = (pos2d - owner.point).squaredLength();
+	float radiusSquared = owner.radius * owner.radius;
+
+	return distanceSquared/radiusSquared;		// alternately could return only distance squared
+}
+
+
+
+// static
+bool Region2::pointInRange(const Vector2& pos2d, const WeightedPoint& owner, const float slop)
+{
+	float adjustedRadius = owner.radius * slop;
+	float adjustedRadiusSquared = adjustedRadius * adjustedRadius;
+
+	float distanceSquared = (pos2d - owner.point).squaredLength();
+	return (distanceSquared < adjustedRadiusSquared);
+}
+
+
+bool Region2::contains(const Vector2& pos2d, const float slop) const
+{
+	if (!pointInRange(pos2d, owner, slop))				// 1.  Distance must be inside the circle
+	{	
+		return false;
+	}
+	else												// 2.	True unless we find someone closer!
+	{
+		return !findCloserOther(pos2d, slop);
+	}
+}
+
+
+bool Region2::findCloserOther(const Vector2& point, const float slop) const
+{
+	for (int i = 0; i < others.size(); ++i) 		// 2.  Point closer to a secondary Point - must be false
+	{	
+		if (closerToOtherPoint(point, owner, others[i], slop))
+		{
+			return true;
+		}
+	}
+	return false;
+}
+
+bool Region2::closerToOtherPoint(const Vector2& pos2d,
+								const WeightedPoint& owner,
+								const WeightedPoint& other,
+								const float slop)
+{
+	if (owner.point == other.point) {
+		return false;
+	}
+
+	float ownerSquaredDistance = (pos2d - owner.point).squaredLength();
+	float otherSquaredDistance = (pos2d - other.point).squaredLength();
+
+	if (otherSquaredDistance < ownerSquaredDistance)
+	{
+		float radiusDelta = owner.radius * (slop - 1.0f);
+		float radiusDeltaSquared = radiusDelta * radiusDelta;
+		if (ownerSquaredDistance - otherSquaredDistance > radiusDeltaSquared)
+			return true;
+	}
+	return false;
+}
+
+} // namespace