axmol/cocos2dx/support/CCPointExtension.cpp

/****************************************************************************
Copyright (c) 2010-2011 cocos2d-x.org
Copyright (c) 2007      Scott Lembcke
Copyright (c) 2010      Lam Pham

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
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all copies or substantial portions of the Software.

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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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****************************************************************************/

#include "CCPointExtension.h"
#include "ccMacros.h" // FLT_EPSILON
#include <stdio.h>
namespace   cocos2d {

#define kCCPointEpsilon FLT_EPSILON

CGFloat
ccpLength(const CCPoint v)
{
	return sqrtf(ccpLengthSQ(v));
}

CGFloat
ccpDistance(const CCPoint v1, const CCPoint v2)
{
	return ccpLength(ccpSub(v1, v2));
}

CCPoint
ccpNormalize(const CCPoint v)
{
	return ccpMult(v, 1.0f/ccpLength(v));
}

CCPoint
ccpForAngle(const CGFloat a)
{
	return ccp(cosf(a), sinf(a));
}

CGFloat
ccpToAngle(const CCPoint v)
{
	return atan2f(v.y, v.x);
}

CCPoint ccpLerp(CCPoint a, CCPoint b, float alpha)
{
	return ccpAdd(ccpMult(a, 1.f - alpha), ccpMult(b, alpha));
}

float clampf(float value, float min_inclusive, float max_inclusive)
{
	if (min_inclusive > max_inclusive) {
		float ftmp;
		ftmp = min_inclusive;
		min_inclusive = max_inclusive;
		max_inclusive = min_inclusive;
	}
	return value < min_inclusive ? min_inclusive : value < max_inclusive? value : max_inclusive;
}

CCPoint ccpClamp(CCPoint p, CCPoint min_inclusive, CCPoint max_inclusive)
{
	return ccp(clampf(p.x,min_inclusive.x,max_inclusive.x), clampf(p.y, min_inclusive.y, max_inclusive.y));
}

CCPoint ccpFromSize(CCSize s)
{
	return ccp(s.width, s.height);
}

CCPoint ccpCompOp(CCPoint p, float (*opFunc)(float)){
	return ccp(opFunc(p.x), opFunc(p.y));
}

bool ccpFuzzyEqual(CCPoint a, CCPoint b, float var)
{
	if(a.x - var <= b.x && b.x <= a.x + var)
		if(a.y - var <= b.y && b.y <= a.y + var)
			return true;
	return false;
}

CCPoint ccpCompMult(CCPoint a, CCPoint b)
{
	return ccp(a.x * b.x, a.y * b.y);
}

float ccpAngleSigned(CCPoint a, CCPoint b)
{
	CCPoint a2 = ccpNormalize(a);	CCPoint b2 = ccpNormalize(b);
	float angle = atan2f(a2.x * b2.y - a2.y * b2.x, ccpDot(a2, b2));
	if( fabs(angle) < kCCPointEpsilon ) return 0.f;
	return angle;
}

CCPoint ccpRotateByAngle(CCPoint v, CCPoint pivot, float angle) {
	CCPoint r = ccpSub(v, pivot);
	float t = r.x;
	float cosa = cosf(angle), sina = sinf(angle);
	r.x = t*cosa - r.y*sina;
	r.y = t*sina + r.y*cosa;
	r = ccpAdd(r, pivot);
	return r;
}

bool ccpLineIntersect(CCPoint p1, CCPoint p2, 
					  CCPoint p3, CCPoint p4,
					  float *s, float *t){
	CCPoint p13, p43, p21;
	float d1343, d4321, d1321, d4343, d2121;
	float numer, denom;
	
	p13 = ccpSub(p1, p3);
	
	p43 = ccpSub(p4, p3);
	
	//Roughly equal to zero but with an epsilon deviation for float 
	//correction
	if (ccpFuzzyEqual(p43, CCPointZero, kCCPointEpsilon))
		return false;
	
	p21 = ccpSub(p2, p1);
	
	//Roughly equal to zero
	if (ccpFuzzyEqual(p21,CCPointZero, kCCPointEpsilon))
		return false;
	
	d1343 = ccpDot(p13, p43);
	d4321 = ccpDot(p43, p21);
	d1321 = ccpDot(p13, p21);
	d4343 = ccpDot(p43, p43);
	d2121 = ccpDot(p21, p21);
	
	denom = d2121 * d4343 - d4321 * d4321;
	if (fabs(denom) < kCCPointEpsilon)
		return false;
	numer = d1343 * d4321 - d1321 * d4343;
	
	*s = numer / denom;
	*t = (d1343 + d4321 *(*s)) / d4343;
	
	return true;
}

float ccpAngle(CCPoint a, CCPoint b)
{
	float angle = acosf(ccpDot(ccpNormalize(a), ccpNormalize(b)));
	if( fabs(angle) < kCCPointEpsilon ) return 0.f;
	return angle;
}
}//namespace   cocos2d