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hitTest globalToLocal or other

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Hello!
I'm trying to count how many turns the yellow dot (this.area_mc.yellowDot_mc) makes before reaching the center or edge.
The yellow dot goes from the edge to the center and then back. I placed a vertical rectangle (rect_mc) and tried to identify the number of turns made with hitTest, but I don't think I was able to make the coordinate transformation work. The rectangle can be either inside area_mc or outside, but the yellow dot must be inside the area. I tried all localToGlobal, localToLocal, globalToLocal methods but I was unsuccessful. link to the .fla file: https://drive.google.com/file/d/1UPHJDcEc6sps58bExh6dNnwDuAXLwLJ8/view?usp=sharing

I thank you for your help.

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JoãoCésar17023019

Community Expert

Hi.

If you want to stick to the collision detection approach, you just need to change this line:

var pt = yellowDot_mc.localToLocal(0, 0, rect_mc); // instead of ...(yellowDot_mc.x, yellowDot_mc.y, rect_mc);

This method expects internal coordinates.

Regards,

JC

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kglad

Community Expert

in general, a hittest isn't going to work for this unless you add constraints and are careful to ensure exactly one + hittest per 2 pi revolution of the dot.

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Vladin M. Mitov

Inspiring

A suggestion: Why don't you convert the coordinates of the yellow point to polar coordinates and compare θ to some predefined value? In this way, it will be clear when the point crosses a given "meridian", despite of the distance to the pole.

function cartesianToPolar( centerX, centerY, x, y ){
	var dx = x - centerX;
	var dy = y - centerY;
	var r = Math.sqrt( dx * dx + dy * dy );
	var theta = Math.atan2( dy, dx );
	return { r:r, theta:theta };
}

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- Vlad: UX and graphic design, Flash user since 1998Member of Flanimate Power Tools team - extensions for character animation

D

du33044471t41kAuthor

Participant

Your solution is very elegant. Congratulations and thank you!

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kglad

Community Expert

what's this supposed to do

createjs.Ticker.setInterval( tempoDeMovimento ); /*tempo de atualização*/

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D

du33044471t41kAuthor

Participant

This is the 200 ms time interval listener that calls the fn_Spin( ) function that increments and decrements the values for sine and cosine variations, causing the yellow dot to move in both directions.

/*update time do dot move */

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kglad

Community Expert

not much is saved by converting to polar. you can just check the angle (and, if you find it easier, you can change the angle and angle_inc variable names to the ones you used):

var rect_mc = this.area_mc.rect_mc;

var area_mc = this.area_mc;

var yellowDot_mc = this.area_mc.yellowDot_mc;

var tempoDeMovimento = 20; // milissegundos para o listener

var angle = 0;

var angle_inc = .1; //para incemento ser igual ao índice

var seno;

var cos;

var circRadius = 300; /*raio máximo*/

var flagSentido = 'reduzindo'; /*direção sentido centro ou borda*/

var contarChamadasDeMovimentos = 0;

var contarVoltas = 0;

var count = 0;

createjs.Ticker.addEventListener("tick", fn_Spin);

createjs.Ticker.setInterval( tempoDeMovimento ); /*tempo de atualização*/

function fn_Spin(event) {

seno = Math.sin ( -angle ) * circRadius;

cos = Math.cos ( -angle ) * circRadius;

// new code

angle = (angle+.1);

if(angle>=Math.PI*2){

angle=0;

count++;

console.log(count);

}

if ( circRadius < 0 ) {

flagSentido = 'crescendo';

contarVoltas = 0;

console.log(count);

count = 0;

console.log('< 0 ')

} else if ( circRadius > 300 ) {

flagSentido = 'reduzindo';

contarVoltas = 0;

console.log(count);

count = 0;

console.log('> 300 ')

}

if ( flagSentido == 'crescendo' ) {

circRadius = circRadius + .1;

} else if ( flagSentido == 'reduzindo' ) {

circRadius = circRadius - .1;

}

yellowDot_mc.x = seno;

yellowDot_mc.y = cos;

};

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