Graal Forums - Circle polygon maybe?

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Circle polygon maybe?

I've been searching for a way to draw a circle and then from the center of the circle designate different areas (such as Up, Left, Right, Down = 90degrees) from the circle. I don't understand drawpolygon(), and I won't pretend to. I was also wondering if I do get the circle or areas created could they be hidden. I am really not sure how to accomplish this and I can't use an image for the circle.

To draw a circle you'll need to use sine and cosine

PHP Code:


		
			
temp.circle = NULL;



for ( temp.a = 0; temp.a < ( 2 * pi); temp.a += ( pi / 32);)

{



  temp.circle.add( player.x + 5 * cos( temp.a));

  temp.circle.add( player.y - 5 * sin( temp.a));



}



showPoly( 1, temp.circle);

Basically adjust the 32 is the number of sides in the circle. It's not a true circle, but visually it's pretty close, increase it for a smoother edges, but costs for cpu time.

To get a a circle on a quadrant plane you use
X = ORGINX + RADIUS * cos( ANGLE);
Y = ORGINY - RADIUS * sin( ANGLE);

Orgins are the center x/y points of the circle
Radius is the number of tiles for the center point
Angle is the well the angle from the center that we are drawing

As for moving along angles, it involves sine and cosine again.

PHP Code:


		
			
temp.angle = getangle( vecx( player.dir), vecy( player.dir));



player.x += cos( temp.angle) * 0.5;

player.y += -sin( temp.angle) * 0.5;

Basically getangle() works by getting values and computing its angle
So it gets values in vectors. Grall operates as so, East is 0/360 degrees and north is 90 degress and so forth.

It'd be better to define how many vertices for the loop.

PHP Code:


		
			
temp.vertices = 32;
temp.radius = 3;
temp.circle = new[0];
temp.O = {player.x + 1.5,player.y + 2};
for (temp.i=0;temp.i<temp.vertices;temp.i++) {
  temp.a = (pi*2)*temp.i;
  temp.circle.add(temp.O[0] + cos(temp.a)*temp.radius);
  temp.circle.add(temp.O[1] - sin(temp.a)*temp.radius);
}
showpoly(200,temp.circle);

At least, that's my opinion. I find it easier to read.

Ok Thanks, the circle works fine, but I can't seem to getangle() to show the angle of said circle. I am unsure of how to get the angle of the circle.
Sorry I could also use a little help with delta x and delta y (Like if the mouse is in front of the player and the player is following it) I have tried getdir() but it only works for Right and Down.

Quote:

Originally Posted by kingcj (Post 1622660)

getangle and getdir are quite simple after you understand it. You pass it the delta (final position minus the initial position) values between two points and it'll give you the angle/direction towards the final position.

PHP Code:


		
			
//#CLIENTSIDE

function onCreated() setTimer(0.05);



function onTimeout() {

  temp.delta_x = mousex - player.x;

  temp.delta_y = mousey - player.y;

  temp.ang = getangle(temp.delta_x, temp.delta_y);

  temp.ndir = getdir(temp.delta_x, temp.delta_y);

  with (findimg(200)) {

    x = player.x + 1 + cos(temp.ang) * 5;

    y = player.y + 1 - sin(temp.ang) * 5;

    image = "block.png";

  }

  with (findimg(201)) {

    x = mousex;

    y = mousey - 0.5;

    text = temp.ang SPC radtodeg(temp.ang);

    textshadow = true;

  }

  player.dir = temp.ndir;

  setTimer(0.05);

}

Thank you all I believe I understand it now!