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resources/app/client-esm/canvas/sources/point-sound-source.mjs

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+import BaseEffectSource from "./base-effect-source.mjs";
+import PointEffectSourceMixin from "./point-effect-source.mjs";
+
+/**
+ * A specialized subclass of the BaseEffectSource which describes a point-based source of sound.
+ * @extends {BaseEffectSource}
+ * @mixes {PointEffectSource}
+ */
+export default class PointSoundSource extends PointEffectSourceMixin(BaseEffectSource) {
+
+  /** @override */
+  static sourceType = "sound";
+
+  /** @override */
+  get effectsCollection() {
+    return canvas.sounds.sources;
+  }
+
+  /* -------------------------------------------- */
+
+  /** @inheritDoc */
+  _getPolygonConfiguration() {
+    return Object.assign(super._getPolygonConfiguration(), {useThreshold: true});
+  }
+
+  /* -------------------------------------------- */
+
+  /**
+   * Get the effective volume at which an AmbientSound source should be played for a certain listener.
+   * @param {Point} listener
+   * @param {object} [options]
+   * @param {boolean} [options.easing]
+   * @returns {number}
+   */
+  getVolumeMultiplier(listener, {easing=true}={}) {
+    if ( !listener ) return 0;                                        // No listener = 0
+    const {x, y, radius} = this.data;
+    const distance = Math.hypot(listener.x - x, listener.y - y);
+    if ( distance === 0 ) return 1;
+    if ( distance > radius ) return 0;                                // Distance outside of radius = 0
+    if ( !this.shape?.contains(listener.x, listener.y) ) return 0;    // Point outside of shape = 0
+    if ( !easing ) return 1;                                          // No easing = 1
+    const dv = Math.clamp(distance, 0, radius) / radius;
+    return (Math.cos(Math.PI * dv) + 1) * 0.5;                        // Cosine easing [0, 1]
+  }
+}