feat: more dynamic collision semantics

packages/physics/matter/world.js

@@ -36,9 +36,16 @@ export class World extends AbstractWorld {
         const {bodyA, bodyB} = pair;
         const entityA = this.entities.get(Body.lookupBody(bodyA));
         const entityB = this.entities.get(Body.lookupBody(bodyB));
-        if (entityA && entityB) {
-          entityA.emit(eventName, entityB);
-          entityB.emit(eventName, entityA);
+        if (
+          entityA && entityA.is('collider')
+          && entityB && entityB.is('collider')
+        ) {
+          if (entityA.collidesWith(entityB)) {
+            entityA.emit(eventName, entityB);
+          }
+          if (entityB.collidesWith(entityA)) {
+            entityB.emit(eventName, entityA);
+          }
         }
       });
     });

packages/physics/traits/collider.trait.js

@@ -1,3 +1,4 @@
+import {behaviorItemFromJSON, createContext} from '@avocado/behavior';
 import {compose} from '@avocado/core';
 import {StateProperty, Trait} from '@avocado/entity';
 
@@ -12,6 +13,8 @@ export class Collider extends decorate(Trait) {
       collidesWithGroups: [
         'default',
       ],
+      collisionEndActions: undefined,
+      collisionStartActions: undefined,
       collisionGroup: 'default',
       isSensor: false,
     }
@@ -29,8 +32,10 @@ export class Collider extends decorate(Trait) {
 
   constructor(entity, params, state) {
     super(entity, params, state);
+    this._collisionActions = [];
     this._collisionGroup = this.params.collisionGroup;
     this._collidesWithGroups = this.params.collidesWithGroups;
+    this._doesNotCollideWith = [];
     this._isCollidingWith = [];
     this._isSensor = this.params.isSensor;
   }
@@ -55,6 +60,22 @@ export class Collider extends decorate(Trait) {
     return this._isSensor;
   }
 
+  pushActionBundle(paramActions, other) {
+    const actions = behaviorItemFromJSON(paramActions);
+    const context = createContext();
+    context.set('entity', this.entity);
+    context.set('other', other);
+    const bundle = {
+      actions,
+      context,
+    };
+    this._collisionActions.push(bundle);
+    actions.once('actionsFinished', () => {
+      const index = this._collisionActions.indexOf(bundle);
+      this._collisionActions.splice(index, 1);
+    });
+  }
+
   listeners() {
     return {
 
@@ -62,6 +83,9 @@ export class Collider extends decorate(Trait) {
         const index = this._isCollidingWith.indexOf(other);
         if (-1 !== index) {
           this._isCollidingWith.splice(index, 1);
+          if (this.params.collisionEndActions) {
+            this.pushActionBundle(this.params.collisionEndActions, other);
+          }
         }
       },
 
@@ -69,6 +93,9 @@ export class Collider extends decorate(Trait) {
         const index = this._isCollidingWith.indexOf(other);
         if (-1 === index) {
           this._isCollidingWith.push(other);
+          if (this.params.collisionStartActions) {
+            this.pushActionBundle(this.params.collisionStartActions, other);
+          }
         }
       },
 
@@ -83,10 +110,17 @@ export class Collider extends decorate(Trait) {
     return {
 
       collidesWith: (entity) => {
-        const collisionGroup = entity.collisionGroup();
+        if (-1 !== this._doesNotCollideWith.indexOf(entity)) {
+          return false;
+        }
+        const collisionGroup = entity.collisionGroup;
         return -1 !== this._collidesWithGroups.indexOf(collisionGroup);
       },
 
+      doesNotCollideWith: (entity) => {
+        return !this.entity.collidesWith(entity);
+      },
+
       releaseAllCollisions: () => {
         for (let i = 0; i < this._isCollidingWith.length; i++) {
           const entity = this._isCollidingWith[i];
@@ -95,6 +129,28 @@ export class Collider extends decorate(Trait) {
         this._isCollidingWith = [];
       },
 
+      setDoesCollideWith: (entity) => {
+        const index = this._doesNotCollideWith.indexOf(entity);
+        if (-1 !== index) {
+          this._doesNotCollideWith.splice(index, 1);
+        }
+      },
+
+      setDoesNotCollideWith: (entity) => {
+        if (-1 === this._doesNotCollideWith.indexOf(entity)) {
+          this._doesNotCollideWith.push(entity);
+        }
+      },
     };
   }
+
+  tick(elapsed) {
+    if (AVOCADO_SERVER) {
+      for (let i = 0; i < this._collisionActions.length; ++i) {
+        const {actions, context} = this._collisionActions[i];
+        actions.tick(context, elapsed);
+      }
+    }
+  }
+
 }