Question

I do not find what’s the problem. I am using ccpToAngle() to find an angle of vector but can’t get proper angle. My ball is launched/initial position at cpp(170,40) and using swipe i want to throw it.
I wrote to find an angle,

 -(void) ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event {

    CGPoint location = [touch locationInView: [touch view]];
    CGPoint vector = ccpSub(location, ccp(170 ,40));
    normalVector = ccpNormalize(vector);
    float angleRads = ccpToAngle(normalVector);
    float angle = CC_RADIANS_TO_DEGREES(angleRads);
   }

but here if i swiped more then angle is increased. I think, swipe in same line/direction the angle should be same every time. but here, I am getting angle between 70 to 90 degrees only, if swipe more then angle is near to 60,66 degrees.

I want angle between 0 to 180 degrees. is it possible that it can consider ccp(170 ,40) as axis origin & find an angle of vector in Cocos2d?

Thanks In advance.

Answer 1

if you want to find an angle of swipe you have to use trigonometry here..

Here is some that can help you..

- ( void ) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
   locationTouchBegan = [touch locationInView: [touch view]];
    //location is The Point Where The User Touched
    locationTouchBegan = [[CCDirector sharedDirector] convertToGL:locationTouchBegan];
    //Detect the Touch On Ball
    if(CGRectContainsPoint([ball boundingBox], locationTouchBegan))
    {
        isBallTouched=YES;
    } 

}

this how you detect that ball is touched

Now on touch end we can calculate the direction.

- ( void ) ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
   locationTouchEnded = [touch locationInView: [touch view]];
    locationTouchEnded = [[CCDirector sharedDirector] convertToGL:locationTouchEnded];
    [self calculateDirections];
}

this is how we calculate direction.

-(void)calculateDirections
{
    if (isBallTouched==YES )
    {
        perpendicularBig = screenSize.height - ball.position.x;
        baseSmall = screenSize.width/2 - locationTouchEnded.x; // if the ball is at center.
        perpendicularSmall=locationTouchEnded.y - ball.position.x;
        baseBig=(perpendicularBig*baseSmall)/perpendicularSmall;
        endPoint=ccp(screenSize.width/2 - baseBig,320); //320 can replace by the value of end point y where you want to end the ball run. 
        [self moveBall:3.0f];
    }
}
-(void)moveBall:(float)duration
{

    [ball runAction:[CCJumpTo actionWithDuration:duration position:ccp(endPoint.x,endPoint.y) height:20 jumps:1]];
    isBallTouched = NO;
}