Ellipse random() is incorrect

[budda]

This Issue is about

• A bug in the API:

  • Phaser version(s): 2.10.3

  • What should happen: points returned up to the circumference of the defined ellipse
    

  • What happens instead: points returned in the centre with a large padding around ellipse edge.
    

[budda]

Test code - https://codepen.io/budda/pen/jzdboZ

[budda]

Comment from @photonstorm phaserjs/phaser#3534 (comment)

Actually, I think that codepen is showing a different issue. The ellipse has been defined with a size of 200x300, but the graphics.drawEllipse has drawn it at 400x600.

[samme]

The confusion is because the arguments are different:

Phaser.Ellipse(left, top, width, height)

graphics.drawEllipse(centerX, centerY, halfWidth, halfHeight)

Nonetheless the points returned by Ellipse#random seem to be placed incorrectly. They are centered on (x, y), but they should be centered on (x + width / 2, y + y / 2). https://codepen.io/samme/pen/ZxwMMN.

Phaser.Utils.Debug#geom seems to have the same problem.

[budda]

Okay, new test random code sorts out the random points - https://codepen.io/budda/pen/KoJOXB

I'm not familiar with the geom debug stuff, I presume it's something wrong on the line

this.context.ellipse(object.x - this.game.camera.x, object.y - this.game.camera.y, object.width/2, object.height/2, 0,2 * Math.PI,false);

But i'm not sure what this is doing with the camera stuff?

[budda]

Also, inline documentation needs correcting as its not halfWidth & halfHeight that should be passed in.

Current, incorrect in Graphics.js ...

/**
 * Draws an ellipse.
 *
 * @method Phaser.Graphics#drawEllipse
 * @param x {Number} The X coordinate of the center of the ellipse
 * @param y {Number} The Y coordinate of the center of the ellipse
 * @param width {Number} The half width of the ellipse
 * @param height {Number} The half height of the ellipse
 * @return {Graphics}
 */
Phaser.Graphics.prototype.drawEllipse 

Because I believe, the width & height is then divided in half on our behalf in the function:

this.drawShape(new Phaser.Ellipse(x-(width/2), y-(height/2), width, height));

[samme]

@param width {Number} The half width of the ellipse
@param height {Number} The half height of the ellipse

The descriptions are correct. They should probably be renamed as halfWidth and halfHeight.

[budda]

But that would suggest that the final X & Y coord is a quarter as it divides the width again inside the method?

My head is mangled following this Ellipse lark now!

[samme]

Divides the width again inside which method?

[budda]

Phaser.Graphics.prototype.drawEllipse