Implement transforms cache to reduce number of transform calculations

Flowm · Jul 3, 2023 · bb0f830 · bb0f830
1 parent 534acea
commit bb0f830
Show file tree

Hide file tree

Showing 2 changed files with 65 additions and 0 deletions.
diff --git a/src/modules/SatelliteProperties.js b/src/modules/SatelliteProperties.js
@@ -8,6 +8,7 @@ import "./util/CesiumSampledPositionRawValueAccess";
 
 import satvisIcon from "../assets/android-chrome-192x192.png";
 import { CesiumCallbackHelper } from "./util/CesiumCallbackHelper";
+// import { CesiumTransformsCache } from "./util/CesiumTransformsCache";
 
 export class SatelliteProperties {
   constructor(tle, tags = []) {
@@ -177,12 +178,14 @@ export class SatelliteProperties {
     const positionInertialTEME = this.computePositionInertialTEME(timestamp);
 
     const temeToFixed = Cesium.Transforms.computeTemeToPseudoFixedMatrix(timestamp);
+    // const temeToFixed = CesiumTransformsCache.getTemeToPseudoFixedMatrix(timestamp);
     if (!Cesium.defined(temeToFixed)) {
       console.error("Reference frame transformation data failed to load");
     }
     const positionFixed = Cesium.Matrix3.multiplyByVector(temeToFixed, positionInertialTEME, new Cesium.Cartesian3());
 
     const fixedToIcrf = Cesium.Transforms.computeFixedToIcrfMatrix(timestamp);
+    // const fixedToIcrf = CesiumTransformsCache.getFixedToIcrfMatrix(timestamp);
     if (!Cesium.defined(fixedToIcrf)) {
       console.error("Reference frame transformation data failed to load");
     }

diff --git a/src/modules/util/CesiumTransformsCache.js b/src/modules/util/CesiumTransformsCache.js
@@ -0,0 +1,62 @@
+import * as Cesium from "cesium";
+
+export class CesiumTransformsCache {
+  static cache = {
+    temeToPseudoFixed: {
+      stats: {
+        calls: 0,
+        miss: 0,
+      },
+    },
+    fixedToIcrfMatrix: {
+      stats: {
+        calls: 0,
+        miss: 0,
+      },
+    },
+  };
+
+  /**
+   * Computes and caches a rotation matrix to transform a point or vector from the Earth-Fixed frame axes (ITRF)
+   * to the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes
+   * at a given time
+   * @param {JulianDate} time The time at which to compute the rotation matrix.
+   * @returns {Matrix3} The rotation matrix
+   */
+  static getTemeToPseudoFixedMatrix(time) {
+    const cache = CesiumTransformsCache.cache.temeToPseudoFixed;
+    const key = `${time.dayNumber}-${Math.floor(time.secondsOfDay)}`;
+    // const key = Cesium.JulianDate.toIso8601(time, 0);
+    if (!cache[key]) {
+      cache[key] = Cesium.Transforms.computeTemeToPseudoFixedMatrix(time);
+      cache.stats.miss += 1;
+    }
+    cache.stats.calls += 1;
+    if (cache.stats.calls % 10000 === 0) {
+      console.log(`getTemeToPseudoFixedMatrix: ${cache.stats.calls} calls, ${cache.stats.miss} misses Ratio: ${cache.stats.miss / cache.stats.calls}`);
+    }
+    return cache[key];
+  }
+
+  /**
+   * Computes and caches a rotation matrix to transform a point or vector from the Earth-Fixed frame axes (ITRF)
+   * to the International Celestial Reference Frame (GCRF/ICRF) inertial frame axes
+   * at a given time
+   * @param {JulianDate} time The time at which to compute the rotation matrix.
+   * @returns {Matrix3} The rotation matrix
+   */
+  static getFixedToIcrfMatrix(time) {
+    const cache = CesiumTransformsCache.cache.fixedToIcrfMatrix;
+    const key = `${time.dayNumber}-${Math.floor(time.secondsOfDay)}`;
+    // const key = Cesium.JulianDate.toIso8601(time, 0);
+    if (!cache[key]) {
+      cache[key] = Cesium.Transforms.computeFixedToIcrfMatrix(time);
+      cache.stats.miss += 1;
+    }
+    cache.stats.calls += 1;
+    if (cache.stats.calls % 10000 === 0) {
+      console.log(`getFixedToIcrfMatrix: ${cache.stats.calls} calls, ${cache.stats.miss} misses Ratio: ${cache.stats.miss / cache.stats.calls}`);
+    }
+    return cache[key];
+  }
+}