# How would you implement this?

**URL:** <https://phaser.discourse.group/t/how-would-you-implement-this/4968>\
**Category:** Phaser 3\
**Created:** [January 22, 2020, 5:34pm UTC](https://phaser.discourse.group/t/how-would-you-implement-this/4968 "2020-01-22T17:34:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![basiclaser](https://yyz2.discourse-cdn.com/free1/user_avatar/phaser.discourse.group/basiclaser/32/242_2.png) [@basiclaser](https://phaser.discourse.group/u/basiclaser)\
**Post date:** [January 22, 2020, 5:34pm UTC](https://phaser.discourse.group/t/how-would-you-implement-this/4968/1 "2020-01-22T17:34:26Z")

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![Screenshot 2020-01-22 at 18.25.00](https://global.discourse-cdn.com/free1/uploads/phaser1/original/2X/b/b472f80eb8b6dc30fa8bc8cab034e48155997174.png)  
In my game, the player flies a little spaceship through the gaps in the ring in the center of the screen, which are constantly growing from the center ( kind of like starfox ) . The rings also spin around concentrically.

I’m currently using phaser3 GRAPHICS.ARC to draw, but I’m not sure how to handle collision.  
Is there someway to get all the points of an arc, to make a polygon in matterJS?  
Or can I somehow detect in a primitive way just that the user passed through the opening in the ring instead?  
Maybe i could write my own simple scaling circle polygon maker, it doesn’t have to be 100% accurate.

What do you think? Is there a built in way to detect “ring-like” collision, or should i write my own thing?

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<div class="post-metadata">

**Author:** ![SiderProg](https://yyz2.discourse-cdn.com/free1/user_avatar/phaser.discourse.group/siderprog/32/2533_2.png) [@SiderProg](https://phaser.discourse.group/u/SiderProg)\
**Post date:** [January 24, 2020, 5:56pm UTC](https://phaser.discourse.group/t/how-would-you-implement-this/4968/2 "2020-01-24T17:56:53Z")

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It should help you

> **[“Dash N Blast” HTML5 prototype updated: added obstacles and collision...](https://www.emanueleferonato.com/2019/08/02/dash-n-blast-html5-prototype-updated-added-obstacles-and-collision-detection-without-physics-engines/)**
>
> Circle Vs Circle Arc collision is the concept behind the next step of