COCOS2DX extended Ccaction implements sprite parabolic motion

Simulates the parabolic motion of an object under gravity (ignoring air resistance) without the use of a physical engine. The position of the starting point of the movement, the end position, the gravitational acceleration g and the firing angle of the starting point are given as parameters.

First, the initial velocity of the object on the x-axis and the y-axis is obtained according to the known conditions, and then the motion trajectory is obtained according to the formula F (t) =v0t+0.5*at2.

Class ccparabolamove inherit from Ccaction.

1ccparabolamove* Ccparabolamove::create (Constccpoint& StartPosition,Constccpoint& Endposition,floatAnglefloatGfloat&return_duration)2 {3Ccparabolamove *pret =NewCcparabolamove ();4     floatvx0,vy0, x1, y1, duration;5 6X1 = endposition.x-startposition.x;7Y1 = endposition.y-Startposition.y
8X1/=Pixels_per_meter;//pixels to meters conversion, pixels_per_meter for conversion coefficients, set here to9Y1/=Pixels_per_meter;TenAngle = angle*3.14/ the;//convert T to radian One  A     if(x1<0) -     { -Angle *=-1; the     } -  -vx0 = X1*sqrt (g/2/(X1*tan (angle)-y1)); //Find the initial speed  -Vy0 = vx0 *Tan (angle); +  -Duration = x1/vx0; //Find out the time of the whole movement  +Return_duration =duration; //Duration is returned by parameter
 APret->initwithduration (duration,startposition, Endposition, Angle,g, vx0, vy0); atPret->autorelease (); -  -     returnPRet; -}

Create () is a static function, so assigning values to non-static member variables is implemented in Initwithduration ():

1 BOOLCcparabolamove::initwithduration (floatDurationConstccpoint& StartPosition,Constccpoint& Endposition,floatAnglefloatGfloatVx0,floatvy0)2 {3     if(ccactioninterval::initwithduration (duration))4     {5m_vx0 =vx0;6M_vy0 =vy0;7M_startposition =startposition;8M_endposition =endposition;9Angle = angle*3.14/ the;//convert T to radianTenM_angle =angle; OneM_dur =duration; AM_tan_a =Tan (angle); -M_g =G; -         return true; the     } -  -     return false; -}

At Runaction, Startwithtarget (Ccnode *ptarget) is called first, through Ptarget, as an object pointer to the execution of the action:

1 void Ccparabolamove::startwithtarget (Ccnode *ptarget)2{3     Ccactioninterval::startwithtarget (ptarget); 4 5 }

The parameter T in update (float t) represents the ratio of the current motion time to the duration of the entire motion, ranging from 0 to 1.

1 voidCcparabolamove::update (floatt)2 {3     if(M_ptarget)4     {5         floatElapsed = T *m_fduration; //Get the current exercise time 6         floatdiff_x = m_vx0 *elapsed;7         floatdiff_y = m_vy0 * Elapsed-0.5* M_g * Elapsed *elapsed;8 9Ccpoint Newpos = Ccpadd (M_startposition, CCP (diff_x * pixels_per_meter, diff_y *pixels_per_meter)); //units converted from meters to pixels TenM_ptarget->setposition (newpos); One  A      -     } -}

COCOS2DX extended Ccaction implements sprite parabolic motion