Add event/trigger and bounds getter

Engine/src/live/Zone.ts

@@ -3,11 +3,27 @@ import { SegmentZone } from '../data/segment'
 
 export class Zone {
   fixture: planck.Fixture|undefined
-  type: 'solid'|'fluid'
+  type: 'solid'|'fluid'|'trigger'
   points: [number, number][]
+  event: string = ''
   constructor(z: SegmentZone) {
     this.type = z.type
     this.points = z.points.map(v=>[v[0], v[1]])
+    this.event = z.event
+  }
+  get bounds(): [number, number, number, number] {
+    let xs = this.points.map(v=>v[0])
+    let ys = this.points.map(v=>v[1])
+    let minX = Math.min(...xs)
+    let minY = Math.min(...ys)
+    let maxX = Math.max(...xs)
+    let maxY = Math.max(...ys)
+    return [
+      minX,
+      minY,
+      maxX-minX,
+      maxY-maxY,
+    ]
   }
 }