X-Git-Url: https://git.r.bdr.sh/rbdr/serpentity/blobdiff_plain/990e42e786c23c83960a15b9ea6cafc914a7c472..d0eb71f3e1f7a8fb227f9fd9286c9d9f041fcce0:/lib/serpentity.js

diff --git a/lib/serpentity.js b/lib/serpentity.js
new file mode 100644
index 0000000..c5ccc97
--- /dev/null
+++ b/lib/serpentity.js
@@ -0,0 +1,248 @@
+'use strict';
+
+/*
+Serpentity is a simple entity framework inspired by Ash.
+
+Usage:
+
+    let Serpentity = require('serpentity');
+
+## Instantiating an engine
+
+    let engine = Serpentity();
+
+Add entities or systems, systems are added with a priority (the smaller
+the number, the earlier it will be called):
+
+    engine.addEntity(entityFactory());
+    engine.addSystem(new GameSystem(), priority);
+
+Update all systems:
+
+    engine.update(dt);
+
+Remove entities or systems:
+
+    engine.removeEntity(entityReference);
+    engine.removeSystem(systemReference);
+
+## Creating Entities
+
+Entities are the basic object of Serpentity, and they do nothing.
+
+    let entity = new Serpentity.Entity();
+
+All the behavior is added through components
+
+## Creating Components
+
+Components define data that we can add to an entity. This data will
+eventually be consumed by "Systems"
+
+    let PositionComponent = class PositionComponent extends Serpentity.Component {
+      constructor (config) {
+        this.x = 0;
+        this.y = 0;
+
+        super(config);
+      }
+    };
+
+You can add components to entities by using the add method:
+
+    entity.addComponent(new PositionComponent());
+
+
+Systems can refer to entities by requesting nodes.
+
+## Working with Nodes
+
+Nodes are sets of components that you define, so your system can require
+entities that always follow the API defined in the node.
+
+    let MovementNode = class MovementNode extends Serpentity.Node;
+    MovementNode.position = PositionComponent;
+    MovementNode.motion = MotionComponent;
+
+You can then request an array of all the nodes representing entities
+that comply with that API
+
+    engine.getNodes(MovementNode);
+
+## Creating Systems
+
+Systems are called on every update, and they use components through nodes.
+
+    let TestSystem = class TestSystem extends Serpentity.System {
+      added (engine){
+        this.nodeList = engine.getNodes(MovementNode);
+      },
+      removed (engine){
+        this.nodeList = undefined;
+      }
+      update (dt){
+        let node;
+        for (node of this.nodeList) {
+          console.log(`Current position is: ${node.position.x},${node.position.y}`);
+        }
+      }
+    };
+
+## That's it
+
+Just run `engine.update(dt)` in your game loop :D
+
+*/
+let Serpentity = class Serpentity {
+
+  constructor (config) {
+    this.systems = [];
+    this.entities = [];
+    this._nodeCollections = [];
+    this._nodeCollectionKeys = [];
+
+    Object.assign(this, config || {});
+  }
+
+  /*
+   * Adds a system to the engine, so its update method will be called
+   * with the others. Triggers added hook.
+   *
+   * returns true if added succesfully, false if already added
+   */
+  addSystem (system, priority) {
+    let lastIndex, found;
+
+    if (this.systems.indexOf(system) >= 0) {
+      return false;
+    }
+
+    system.priority = priority;
+
+    found = false;
+    lastIndex = 0;
+
+    this.systems.some(function findPriority(existingSystem, i) {
+      lastIndex = i;
+      if (existingSystem.priority >= system.priority) {
+        found = true;
+        return true;
+      }
+    });
+
+    if (!found) {
+      lastIndex += 1;
+    }
+
+    this.systems.splice(lastIndex, 0, system);
+    system.added(this);
+    return true;
+  }
+
+  /*
+   * Removes a system from the engine, so its update method will no
+   * longer will be called. Triggers the removed hook.
+   *
+   * returns true if removed succesfully, false if already added
+   */
+  removeSystem (system) {
+    let position;
+
+    position = this.systems.indexOf(system);
+    if (position >= 0) {
+      this.systems[position].removed(this);
+      this.systems.splice(position, 1);
+      return true;
+    }
+
+    return false;
+  }
+
+  /*
+   * Adds an entity to the engine, adds to existing node collections
+   *
+   * returns true if added, false if already there
+   */
+  addEntity (entity) {
+    if (this.entities.indexOf(entity) >= 0) {
+      return false;
+    }
+    this.entities.push(entity);
+
+    this._nodeCollections.forEach(function (collection) {
+      collection.add(entity);
+    });
+
+    return true;
+  }
+
+  /*
+   * Removes entity from system, removing from all node collections
+   *
+   * returns true if removed, false if not present
+   */
+  removeEntity (entity) {
+    let position;
+
+    position = this.entities.indexOf(entity);
+    if (position >= 0) {
+      this._nodeCollections.forEach(function (collection) {
+        collection.remove(entity);
+      });
+
+      this.entities.splice(position, 1);
+      return true;
+    }
+
+    return false;
+  }
+
+  /*
+   * Given a Node Class, retrieves a list of all the nodes for each
+   * applicable entity.
+   */
+  getNodes (nodeType) {
+    let position, nodeCollection;
+
+    position = this._nodeCollectionKeys.indexOf(nodeType);
+
+    if (position >= 0) {
+      return this._nodeCollections[position].nodes;
+    }
+
+    nodeCollection = new Serpentity.NodeCollection({
+      type : nodeType
+    });
+
+    this._nodeCollectionKeys.push(nodeType);
+    this._nodeCollections.push(nodeCollection);
+
+    this.entities.forEach(function (entity) {
+      nodeCollection.add(entity);
+    });
+
+    return nodeCollection.nodes;
+  }
+
+  /*
+   * Calls update for every loaded system.
+   */
+  update (dt) {
+    this.systems.forEach(function (system) {
+      system.update(dt);
+    });
+  }
+};
+
+// Add namespaced objects.
+if (typeof module !== 'undefined' && this.module !== module) {
+  Serpentity.Component = require('./serpentity/component.js');
+  Serpentity.Entity = require('./serpentity/entity.js');
+  Serpentity.Node = require('./serpentity/node.js');
+  Serpentity.NodeCollection = require('./serpentity/node_collection.js');
+  Serpentity.System = require('./serpentity/system.js');
+
+  module.exports = Serpentity;
+} else {
+  window.Serpentity = Serpentity;
+}