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[rbdr/serpentity] / lib / serpentity / serpentity.js
1 if (typeof require !== "undefined") {
2 require("neon");
3 }
4
5 /*
6 Serpentity is a simple entity framework inspired by Ash.
7
8 Usage:
9
10 require('serpentity');
11
12 ## Instantiating an engine
13
14 var engine = Serpentity();
15
16 Add entities or systems, systems are added with a priority (the smaller
17 the number, the earlier it will be called):
18
19 engine.addEntity(entityFactory());
20 engine.addSystem(new GameSystem(), priority);
21
22 Update all systems:
23
24 engine.update(dt);
25
26 Remove entities or systems:
27
28 engine.removeEntity(entityReference);
29 engine.removeSystem(systemReference);
30
31 ## Creating Entities
32
33 Entities are the basic object of Serpentity, and they do nothing.
34
35 var entity = new Serpentity.Entity();
36
37 All the behavior is added through components
38
39 ## Creating Components
40
41 Components define data that we can add to an entity. This data will
42 eventually be consumed by "Systems"
43
44 Class("PositionComponent").inherits(Serpentity.Component)({
45 prototype : {
46 x : 0,
47 y : 0
48 }
49 });
50
51 You can add components to entities by using the add method:
52
53 entity.addComponent(new PositionComponent());
54
55
56 Systems can refer to entities by requesting nodes.
57
58 ## Working with Nodes
59
60 Nodes are sets of components that you define, so your system can require
61 entities that always follow the API defined in the node.
62
63 Class("MovementNode").inherits(Serpentity.Node)({
64 types : {
65 position : PositionComponent,
66 motion : MotionComponent
67 }
68 });
69
70 You can then request an array of all the nodes representing entities
71 that comply with that API
72
73 engine.getNodes(MovementNode);
74
75 ## Creating Systems
76
77 Systems are called on every update, and they use components through nodes.
78
79 Class("TestSystem").inherits(Serpentity.System)({
80 prototype : {
81 added : function added(engine){
82 this.nodeList = engine.getNodes(MovementNode);
83 },
84 removed : function removed(engine){
85 this.nodeList = undefined;
86 }
87 update : function update(dt){
88 this.nodeList.forEach(function (node) {
89 console.log("Current position is: " + node.position.x + "," + node.position.y);
90 });
91 }
92 }
93 });
94
95 ## That's it
96
97 Just run `engine.update(dt)` in your game loop :D
98
99 */
100 Class("Serpentity")({
101 prototype : {
102 systems : null,
103 entities : null,
104 _nodeCollections : null,
105 _nodeCollectionKeys : null,
106
107 init : function init(config) {
108 var property;
109
110 config = config || {};
111
112 this.systems = [];
113 this.entities = [];
114 this._nodeCollections = [];
115 this._nodeCollectionKeys = [];
116
117 for (property in config) {
118 if (config.hasOwnProperty(property)) {
119 this[property] = config[property];
120 }
121 }
122 },
123
124 /*
125 * Adds a system to the engine, so its update method will be called
126 * with the others. Triggers added hook.
127 *
128 * returns true if added succesfully, false if already added
129 */
130 addSystem : function addSystem(system, priority) {
131 var lastIndex, found;
132
133 if (this.systems.indexOf(system) >= 0) {
134 return false;
135 }
136
137 system.priority = priority;
138
139 found = false;
140 lastIndex = 0;
141
142 this.systems.some(function findPriority(existingSystem, i) {
143 lastIndex = i;
144 if (existingSystem.priority >= system.priority) {
145 found = true;
146 return true;
147 }
148 });
149
150 if (!found) {
151 lastIndex += 1
152 }
153
154 this.systems.splice(lastIndex, 0, system);
155 system.added(this);
156 return true;
157 },
158
159 /*
160 * Removes a system from the engine, so its update method will no
161 * longer will be called. Triggers the removed hook.
162 *
163 * returns true if removed succesfully, false if already added
164 */
165 removeSystem : function removeSystem(system) {
166 var position;
167
168 position = this.systems.indexOf(system);
169 if (position >= 0) {
170 this.systems[position].removed(this);
171 this.systems.splice(position, 1);
172 return true;
173 }
174
175 return false;
176 },
177
178 /*
179 * Adds an entity to the engine, adds to existing node collections
180 *
181 * returns true if added, false if already there
182 */
183 addEntity : function addEntity(entity) {
184 if (this.entities.indexOf(entity) >= 0) {
185 return false;
186 }
187 this.entities.push(entity);
188
189 this._nodeCollections.forEach(function (collection) {
190 collection.add(entity);
191 });
192
193 return true;
194 },
195
196 /*
197 * Removes entity from system, removing from all node collections
198 *
199 * returns true if removed, false if not present
200 */
201 removeEntity : function removeEntity(entity) {
202 var position;
203
204 position = this.entities.indexOf(entity);
205 if (position >= 0) {
206 this._nodeCollections.forEach(function (collection) {
207 collection.remove(entity);
208 });
209
210 this.entities.splice(position, 1);
211 return true;
212 }
213
214 return false;
215 },
216
217 /*
218 * Given a Node Class, retrieves a list of all the nodes for each
219 * applicable entity.
220 */
221 getNodes : function getNodes(nodeType) {
222 var position, nodeCollection;
223
224 position = this._nodeCollectionKeys.indexOf(nodeType);
225
226 if (position >= 0) {
227 return this._nodeCollections[position].nodes;
228 }
229
230 nodeCollection = new Serpentity.NodeCollection({
231 type : nodeType,
232 });
233
234 this._nodeCollectionKeys.push(nodeType);
235 this._nodeCollections.push(nodeCollection);
236
237 this.entities.forEach(function (entity) {
238 nodeCollection.add(entity);
239 });
240
241 return nodeCollection.nodes;
242 },
243
244 /*
245 * Calls update for every loaded system.
246 */
247 update : function update(dt) {
248 this.systems.forEach(function (system) {
249 system.update(dt);
250 });
251 }
252 }
253 });
254
255 if (typeof require !== "undefined") {
256 require("./component.js");
257 require("./entity.js");
258 require("./node.js");
259 require("./node_collection.js");
260 require("./system.js");
261 }