closes #1, adds the parallax layer feature

package.json

@@ -1,6 +1,6 @@
 {
   "name": "parallax",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "A parallax module that will enable effortless integration of depth effects into your game.",
   "main": "src/parallax.mjs",
   "scripts": {

src/layer.mjs

@@ -0,0 +1,152 @@
+import { Parallax } from './parallax.mjs';
+
+export class Layer {
+    /**
+     * The configuration object of this layer.
+     * @private
+     * @type {Object}
+     * @param {number} horizontalSpeed - The horizontal speed of the layer.
+     * @param {number} verticalSpeed - The vertical speed of the layer.
+     * @param {number} plane - The plane this parallax layer will occupy.
+     * @param {Diob[] | MapObject[]} backgrounds - An array of instances that will serve as the background. These are automatically toggled to repeat.
+     * @param {Set} instances - A set of instances currently on the layer.
+     */
+    config = {
+        // Move the instance with the camera if the parallax is set to 0
+        horizontalSpeed: 0,
+        verticalSpeed: 0,
+        plane: 1,
+        backgrounds: new Set(),
+        instances: new Set()
+    }
+    /**
+     * Creates a new Parallax layer with the supplied configuration.
+     * When creating a layer, all instances and backgrounds should already be on the map.
+     * @param {Object} pConfig - The configuration of the parallax layer.
+     * @prop {number} pConfig.horizontalSpeed - The horizontal speed of the layer.
+     * @prop {number} pConfig.verticalSpeed - The vertical speed of the layer. 
+     * @prop {number} pConfig.plane - The plane this layer will occupy.
+     * @param {Diob[] | MapObject[]} pConfig.backgrounds - An array of instances that will serve as the background. These are automatically toggled to repeat.
+     * @prop {Diob[] | MapObject[]} pConfig.instances - The instances that will be added to the layer. 
+     */
+    constructor(pConfig) {
+        this.updateConfigSpeed(pConfig, true);
+
+        if (!typeof pConfig.plane === 'number') {
+            Parallax.logger.prefix('Parallax-Module').warn('Expected a number for "pConfig.plane", but received:', typeof pConfig.plane, '\n Default plane of "1" used.');
+        } else {
+            this.config.plane = pConfig.plane;
+        }
+
+        const instanceConfig = {
+            x: this.config.horizontalSpeed,
+            y: this.config.verticalSpeed
+        }
+
+        if (Array.isArray(pConfig.instances)) {
+            pConfig.instances.forEach(pInstance => {
+                pInstance.plane = this.config.plane;
+                this.add(pInstance, instanceConfig)
+            });
+        }
+
+        if (Array.isArray(pConfig.backgrounds)) {
+            // Backgrounds automatically loop
+            instanceConfig.loop = true;
+            pConfig.backgrounds.forEach(pInstance => {
+                pInstance.plane = this.config.plane;
+                this.add(pInstance, instanceConfig)
+            });
+        }
+    }
+    /**
+     * Updates the configuration speed of the layer.
+     * @param {Object} pConfig - The speed configuration of the parallax layer.
+     * @prop {number} pConfig.horizontalSpeed - The horizontal speed of the layer.
+     * @prop {number} pConfig.verticalSpeed - The vertical speed of the layer. 
+     * @param {boolean} pUpdateLayerConfigOnly - If only to update the layer config and not the instance config.
+     */
+    updateConfigSpeed(pConfig, pUpdateLayerConfigOnly) {
+        this.updateHorizontalSpeed(pConfig.horizontalSpeed, pUpdateLayerConfigOnly);
+        this.updateVerticalSpeed(pConfig.verticalSpeed, pUpdateLayerConfigOnly);
+    }
+    /**
+     * Updates the horizontal speed of this layer.
+     * @param {number} pHorizontalSpeed - The new horizontal speed.
+     * @param {boolean} pUpdateLayerConfigOnly - If only to update the layer config and not the instance config.
+     */
+    updateHorizontalSpeed(pHorizontalSpeed, pUpdateLayerConfigOnly) {
+        const inValidHorizontal = pHorizontalSpeed && typeof pHorizontalSpeed !== 'number';
+
+        if (inValidHorizontal) {
+            Parallax.logger.prefix('Parallax-Module').warn('Expected a number for "pHorizontalSpeed", but received:', typeof pHorizontalSpeed);
+            return
+        }
+
+        this.config.horizontalSpeed = pHorizontalSpeed;
+
+        if (!pUpdateLayerConfigOnly) {
+            const update = (pInstance) => {
+                const parallaxInfo = Parallax.instanceWeakMap.get(pInstance);
+                parallaxInfo.x = pVerticalSpeed;
+            }
+
+            this.instances.forEach(pInstance => {
+                update(pInstance);
+            });
+            this.backgrounds.forEach(pInstance => {
+                update(pInstance);
+            });
+        }
+    }
+    /**
+     * Updates the vertical speed of the layer.
+     * @param {number} pVerticalSpeed - The new vertical speed. 
+     * @param {boolean} pUpdateLayerConfigOnly - If only to update the layer config and not the instance config.
+     */
+    updateVerticalSpeed(pVerticalSpeed, pUpdateLayerConfigOnly) {
+        const inValidVertical = pVerticalSpeed && typeof pVerticalSpeed !== 'number';
+
+        if (inValidVertical) {
+            Parallax.logger.prefix('Parallax-Module').warn('Expected a number for "pVerticalSpeed", but received:', typeof pVerticalSpeed);
+            return
+        }
+
+        this.config.verticalSpeed = pVerticalSpeed;
+
+        if (!pUpdateLayerConfigOnly) {
+            const update = (pInstance) => {
+                const parallaxInfo = Parallax.instanceWeakMap.get(pInstance);
+                parallaxInfo.y = pVerticalSpeed;
+            }
+
+            this.instances.forEach(pInstance => {
+                update(pInstance);
+            });
+            this.backgrounds.forEach(pInstance => {
+                update(pInstance);
+            });
+        }
+    }
+    /**
+     * Adds the instance to the parallax layer.
+     * When using this API the instance should already be on the map.
+     * @param {Diob} pInstance - The instance to add to the layer.
+     * @param {Object} pConfig - The personal config of this instance. Akin to the parallax info passed via the `Parallax.add` API.
+     * @prop {number} pConfig.x - The horizontal speed of this instance. (This will be ignored and the layer's speed will be used.)
+     * @prop {number} pConfig.y - The vertical speed of this instance. (This will be ignored and the layer's speed will be used.)
+     * @prop {boolean} pConfig.loop - Whether this instance will be treated as a background and loop seamlessly.
+     */
+    add(pInstance, pConfig) {
+        this.config.instances.add(pInstance);
+        Parallax.add(pInstance, pConfig);
+    }
+    /**
+     * Removes the instance from the parallax layer.
+     * @param {Diob} pInstance - The instance to remove from the layer.
+     */
+    remove(pInstance) {
+        this.config.instances.delete(pInstance);
+        Parallax.remove(pInstance);
+    }
+}