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

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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(const CCPoint& a, const 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(const CCPoint& p, const CCPoint& min_inclusive, const 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(const CCSize& s)
{
	return ccp(s.width, s.height);
}

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

bool ccpFuzzyEqual(const CCPoint& a, const 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(const CCPoint& a, const CCPoint& b)
{
	return ccp(a.x * b.x, a.y * b.y);
}

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

bool ccpLineIntersect(CCPoint A, CCPoint B, 
					  CCPoint C, CCPoint D,
					  float *S, float *T)
{
    // FAIL: Line undefined
    if ( (A.x==B.x && A.y==B.y) || (C.x==D.x && C.y==D.y) )
    {
        return false;
    }

    //  Translate system to make A the origin
    B.x-=A.x; B.y-=A.y;
    C.x-=A.x; C.y-=A.y;
    D.x-=A.x; D.y-=A.y;

    // Cache
    CCPoint C2 = C, D2 = D;

    // Length of segment AB
    float distAB = sqrtf(B.x*B.x+B.y*B.y);

    // Rotate the system so that point B is on the positive X axis.
    float theCos = B.x/distAB;
    float theSin = B.y/distAB;
    float newX = C.x*theCos+C.y*theSin;
    C.y  = C.y*theCos-C.x*theSin; C.x = newX;
    newX = D.x*theCos+D.y*theSin;
    D.y  = D.y*theCos-D.x*theSin; D.x = newX;

    // FAIL: Lines are parallel.
    if (C.y == D.y)
    {
        return false;
    }

    // Discover position of the intersection in the line AB
    float ABpos = D.x+(C.x-D.x)*D.y/(D.y-C.y);

    // Vector CD
    C.x = D2.x-C2.x;
    C.y = D2.y-C2.y;

    // Vector between intersection and point C
    A.x = ABpos*theCos-C2.x;
    A.y = ABpos*theSin-C2.y;

    newX = sqrtf((A.x*A.x+A.y*A.y)/(C.x*C.x+C.y*C.y));
    if(((A.y<0) != (C.y<0)) || ((A.x<0) != (C.x<0)))
        newX *= -1.0f;

    *S = ABpos/distAB;
    *T = newX;

    // Success.
    return true;
}

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