2点のなす角度を計算する

UtilMath.cpp

//
//  UtilMath.cpp
//  HelloCpp
//
//  Created by Shimeji Ozaki on 2013-10-06.
//
//

#include "UtilMath.h"

// PI
float UtilMath::getPI(){
	return PI;
}

// RadToDeg
float UtilMath::getRadToDeg(){
	return RadToDeg;
}

// DegToRad
float UtilMath::getDegToRad(){
	return DegToRad;
}

// distance
float UtilMath::calcDistance2D(const Point& pointA, const Point& pointB){
	
	float distance = sqrt(powf(pointA.x - pointB.x, 2) + powf(pointA.y - pointB.y, 2));
	return distance;
}

// angle(1Point)
float UtilMath::calcAngle2D(const Point& pointCenter, const Point& pointA){
	
	// SamePoint
	if(pointCenter.x == pointA.x && pointCenter.y == pointA.y){
		return 0.0f;
	}
	
	// Horizontal
	if(pointCenter.x == pointA.x){
		if(pointCenter.y < pointA.y){
			return +90.0f;
		}else{
			return -90.0f;
		}
	}
	
	// Vertical
	if(pointCenter.y == pointA.y){
		if(pointCenter.x < pointA.x){
			return 0.0f;
		}else{
			return 180.0f;
		}
	}
	
	float angle = (float)atan((pointA.y - pointCenter.y) / (pointA.x - pointCenter.x)) * RadToDeg;
	if(pointA.y > pointCenter.y && pointA.x > pointCenter.x){
		// 1div
		return angle;
	}else if(pointA.y > pointCenter.y && pointA.x < pointCenter.x){
		// 2div
		return angle + 180;
	}else if(pointA.y < pointCenter.y && pointA.x < pointCenter.x){
		// 3div
		return angle + 180;
	}else{
		// 4div
		return angle + 360;
	}
}

// angle(2Point)
float UtilMath::calcAngle2P2D(const Point& pointCenter, const Point& pointA, const Point& pointB){
	//TODO +-
	float angleA = calcAngle2D(pointCenter, pointA);
	float angleB = calcAngle2D(pointCenter, pointB);
	
	float angleDistance = fabs(angleA - angleB);
	if(angleDistance > 180){
		angleDistance = 360 - angleDistance;
	}
	if(angleA)
	
	return angleDistance;
}

UtilMath.h

//
//  UtilMath.h
//  HelloCpp
//
//  Created by Shimeji Ozaki on 2013-10-06.
//
//

#ifndef __HelloCpp__UtilMath__
#define __HelloCpp__UtilMath__

#define PI       3.141592653f
#define RadToDeg 57.29577951f
#define DegToRad 0.017453293f

#include "cocos2d.h"

USING_NS_CC;

class UtilMath{
	
public:
	
	static float getPI();
	
	static float getRadToDeg();
	
	static float getDegToRad();
	
	static float calcDistance2D(const Point& pointA, const Point& pointB);
	
	// centerとのなす角
	static float calcAngle2D(const Point& pointCenter, const Point& pointA);
	
	// centerから見た、pointAとpointBの角度差
	static float calcAngle2P2D(const Point& pointCenter, const Point& pointA, const Point& pointB);
	
};

#endif /* defined(__HelloCpp__UtilMath__) */