Making Ball Fling in a Curve Direction

Question

I was wondering how to figuring out how to slice a ball (banana kick) by flinging it curve-ways. However, according to the LibGDX's gesture listener, the method for flinging only focuses on a straight direction, whether if the ball went to the left, right, or straight.

@Override
public boolean fling(float velocityX, float velocityY, int button) 
{
    // Set flag for goal.
    gotPoint = false;
    isBallMissed = true;

    // Set flag to enable scrolling goalkeeper when a player's turn as a goalkeeper.
    isAIKicked = false;

    // Re-adjust ball fling coordinates...
    x = velocityX/25;
    y = (velocityY/25) * -1;

    if(!flingLocked && !gotPoint)
    {
        if(y > 100) // --> Checks if the gling power is just right or else it miss.
        {
            if(y > 130) 
            {
                goalpostHit = false;
                crossbarHit = false;
                disableGoal = true;
                meterSpeed = 50f;

            } else {

                goalpostHit = false;
                crossbarHit = true;
                disableGoal = true;
                meterSpeed = 20f;

            }

        } else {

            goalpostHit = true;
            crossbarHit = true;
            disableGoal = false;
            meterSpeed = 3f;

        }
    }

    // Get the value to set the collision on or off.
    bp.setGhostPost(goalpostHit);
    bp.setGhostCrossbar(crossbarHit);

    // For debugging purposes only. Checks if the fling direction of the ball went. (output display console only)
    System.out.println("Hit Post Enabled Status: " + goalpostHit);
    System.out.println("Hit Bar Enabled Status: " + crossbarHit);
    System.out.println("touchUp() at Y: " + y);
    System.out.println("fling() at Y: " + y);
    System.out.println("fling() at X: " + x);

    // For debugging purposes only. Checks if the fling direction of the ball went.
    if(x >= 1)
    {
        directionStatus = "RIGHT";

    } else if(x <= -1) {

        directionStatus = "LEFT";

    } else {

        directionStatus = "FOWARD";

    }

    if(!goalKeeper && !flingLocked && !freezeGame && !isPaused && !gotPoint) // --> Tells is the ball is flinged or not while the player is under kicker role.
    {
        // Play SFX.
        SFX.getBallKicked().play(1f);

        // Set Timer
        timer4 = 0;

        // Set AI's smart level as a goalkeeper
        speedLevel = (rnd.nextInt(175 - 55) + 55);
        isReversed = rnd.nextInt(10);

        // Set mass of a body.
        MassData mass = new MassData();
        mass.mass = 400;

        // Re-create body of the ball.
        wc.getWorld().destroyBody(ballBody);
        ballDef.position.rotate(0f);
        ballDef.angle = 30f;
        ballDef.position.set(rc.getSoccerBallX(), 10);
        ballDef.allowSleep = true;
        ballBody = wc.getWorld().createBody(ballDef);
        ballBody.setActive(true);
        ballBody.applyLinearImpulse(x, y, rc.getSoccerBallX(), 10); // --> Makes the direction go left or right?
        ballBody.applyAngularImpulse(200);
        ballBody.isBullet();
        ballBody.setMassData(mass);
        ballBody.setLinearDamping(-990f); // --> This will set how fast will accelerate the object will fall. Set it to a negative value to increase falling speed.
        ballBody.setGravityScale(0); // --> Set it to negative value and the ball will lift. Set it to a positive value and the ball falls normally.

        // Load the ball.
        ballLoader.attachFixture(ballBody, "soccer ball", ballFixture, rc.getSoccerBallWidth());
        v2.ball_origin = ballLoader.getOrigin("soccer ball", rc.getSoccerBallWidth()).cpy();

        // Disable fling and set timer.
        switchRoleTimer = true;
        flingLocked = true;

        // Action ended per turn.
        if ((noOfTries < 11) && !isSuddenDeathmatch)
        {
            noOfTries++;
        }

        // Disable fling temporarily.
        Gdx.input.setInputProcessor(this);
    }


    return false;
}

What can I do to make the ball fling in curve-ways if I fling it curve-ways? Should I make a flag and mathematically computed the coordinates by analyzing the finger in order to recognize the response of this kind of fling? Take note that I'm making a 2D overview of the soccer game.

Answer 1

i didn't read all of your code but if i get it right you want a curve movement.

in linar algebra you can use vector addition for velocity and acceleration of object

lets say :

  my_pos = (0,0)

  velocity = (1,3)

  acceleration = (0,-1) //gravity?

  do(lets say  every half a second?)
  {
       to_move_x =velocity.x  + acceleration.x  
       to_move_y =velocity.y  + acceleration.y  


       my_pos .x += to_move_x 
       my_pos .y += to_move_y 
   }
   //if (y<0) {y=0} or the object hits ground or solid, stop move loop

first loop to move will be(1,2) and my_pos =(1,2)

second loop to move will be(1,1) and my_pos =(2,3)

third loop to move will be(1,0) and my_pos =(3,3)

fourth loop to move will be(1,-1) and my_pos =(4,2)

which will look like:

           (3,3)
             _
 (2,3) ->   /  \<-(4,2)
 (1,2) ->  /    \<-(5,1)

and thats a curve.

i hope thats what you looked for.

learn linar algebra it solves stuff like that.its very helpful for game dev (and geometry and trigonometry).