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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all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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****************************************************************************/

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

NS_CC_BEGIN

#define kCCPointEpsilon FLT_EPSILON

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

CCFloat
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 CCFloat a)
{
    return ccp(cosf(a), sinf(a));
}

CCFloat
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) {
        CC_SWAP(min_inclusive, max_inclusive, float);
    }
    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 ccpSegmentIntersect(const CCPoint& A, const CCPoint& B, const CCPoint& C, const CCPoint& D)
{
    float S, T;

    if( ccpLineIntersect(A, B, C, D, &S, &T )
        && (S >= 0.0f && S <= 1.0f && T >= 0.0f && T <= 1.0f) )
        return true;

    return false;
}

CCPoint ccpIntersectPoint(const CCPoint& A, const CCPoint& B, const CCPoint& C, const CCPoint& D)
{
    float S, T;

    if( ccpLineIntersect(A, B, C, D, &S, &T) )
    {
        // Point of intersection
        CCPoint P;
        P.x = A.x + S * (B.x - A.x);
        P.y = A.y + S * (B.y - A.y);
        return P;
    }

    return CCPointZero;
}

bool ccpLineIntersect(const CCPoint& A, const CCPoint& B, 
                      const CCPoint& C, const 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;
    }
    const float BAx = B.x - A.x;
    const float BAy = B.y - A.y;
    const float DCx = D.x - C.x;
    const float DCy = D.y - C.y;
    const float ACx = A.x - C.x;
    const float ACy = A.y - C.y;

    const float denom = DCy*BAx - DCx*BAy;

    *S = DCx*ACy - DCy*ACx;
    *T = BAx*ACy - BAy*ACx;

    if (denom == 0)
    {
        if (*S == 0 || *T == 0)
        { 
            // Lines incident
            return true;   
        }
        // Lines parallel and not incident
        return false;
    }

    *S = *S / denom;
    *T = *T / denom;

    // Point of intersection
    // CGPoint P;
    // P.x = A.x + *S * (B.x - A.x);
    // P.y = A.y + *S * (B.y - A.y);

    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;
}

NS_CC_END