feat: basic magnetism

common/traits/magnetic.trait.js

@@ -0,0 +1,84 @@
+import {behaviorItemFromJSON, createContext} from '@avocado/behavior';
+import {compose, Property} from '@avocado/core';
+import {StateProperty, Trait} from '@avocado/entity';
+import {Rectangle, Vector} from '@avocado/math';
+
+import {TraitPlantPacket} from './trait-plant.packet';
+
+const decorate = compose(
+  StateProperty('attraction', {
+    track: true,
+  }),
+);
+
+export class Magnetic extends decorate(Trait) {
+
+  static defaultParams() {
+    return {
+      isAttractor: false,
+    };
+  }
+
+  static defaultState() {
+    return {
+      attraction: 0,
+    };
+  }
+
+  static type() {
+    return 'magnetic';
+  }
+
+  constructor(entity, params, state) {
+    super(entity, params, state);
+  }
+
+  get isAttracted() {
+    return !this.params.isAttractor;
+  }
+
+  get isAttractor() {
+    return !!this.params.isAttractor;
+  }
+
+  tick(elapsed) {
+    if (!this.params.isAttractor) {
+      return;
+    }
+    const attraction = this.entity.attraction;
+    if (0 === attraction) {
+      return;
+    }
+    const layer = this.entity.layer;
+    if (!layer) {
+      return;
+    }
+    const query = Rectangle.compose(
+      Vector.sub(this.entity.position, [32, 32]),
+      [64, 64],
+    );
+    const entities = layer.visibleEntities(query);
+    for (let i = 0; i < entities.length; ++i) {
+      const entity = entities[i];
+      if (!entity.is('magnetic') || !entity.isAttracted) {
+        continue;
+      }
+      if (!entity.is('positioned') || !entity.is('mobile')) {
+        continue;
+      }
+      const distance = Vector.distance(
+        this.entity.position,
+        entity.position,
+      );
+      if (distance > attraction) {
+        continue;
+      }
+      const difference = Vector.sub(this.entity.position, entity.position);
+      const unit = Vector.normalize(difference);
+      const rdiff = 1 - (distance / attraction);
+      const magnitude = 50 * rdiff;
+      entity.applyMovement(Vector.scale(unit, magnitude));
+    }
+  }
+
+}

server/create-entity-for-connection.js

@@ -47,6 +47,11 @@ export function createEntityForConnection(socket) {
       informed: {},
       layered: {},
       listed: {},
+      magnetic: {
+        params: {
+          isAttractor: true,
+        },
+      },
       mobile: {
         state: {
           speed: 100,

server/fixtures/kitty-fire.room.js

@@ -61,12 +61,15 @@ export function kittyFireJSON() {
     roomJSON.layers[0].entities.push(positionedEntityJSON(uri, position));
   }
 
+  for (let i = 0; i < 20; ++i) {
+    addEntityWithRandomPosition('/rock.entity.json');
+  }
   // for (let i = 0; i < 20; ++i) {
   //   addEntityWithRandomPosition('/flower-barrel.entity.json');
   // }
-  for (let i = 0; i < 3; ++i) {
-    addEntityWithRandomPosition('/mama-kitty-spawner.entity.json');
-  }
+  // for (let i = 0; i < 3; ++i) {
+  //   addEntityWithRandomPosition('/mama-kitty-spawner.entity.json');
+  // }
   // for (let i = 0; i < 5; ++i) {
   //   addEntityWithRandomPosition('/fire.entity.json');
   // }

server/fixtures/rock.entity.js

@@ -30,6 +30,11 @@ export function rockJSON() {
   );
   return {
     traits: {
+      collider: {
+        params: {
+          isSensor: true,
+        },
+      },
       existent: {
         state: {
           name: 'Rock',
@@ -51,6 +56,33 @@ export function rockJSON() {
           },
         },
       },
+      layered: {},
+      listed: {},
+      magnetic: {},
+      mobile: {},
+      physical: {},
+      pictured: {
+        params: {
+          images: {
+            initial: {
+              offset: [0, 0],
+              size: [12, 12], // Derive?
+              uri: '/rock.png',
+            },
+          }
+        },
+      },
+      positioned: {},
+      roomed: {},
+      shaped: {
+        params: {
+          shape: {
+            type: 'rectangle',
+            position: [0, 0],
+            size: [12, 12],
+          },
+        },
+      },
       spawner: {
         params: {
           spawns: {
@@ -59,7 +91,8 @@ export function rockJSON() {
             },
           },
         },
-      }
+      },
+      visible: {},
     },
   };
 }