Merge pull request #7959 from tinco/optimize-approx-terrain-heights

Optimize approximateTerrainHeights file for quicker page loads (Solves #6557)

CHANGES.md

@@ -15,6 +15,7 @@ Change Log
 * Fixed 3D tiles style coloring when multiple tilesets are in the scene [#8051](https://github.com/AnalyticalGraphicsInc/cesium/pull/8051)
 * Improved display of tile coordinates for `TileCoordinatesImageryProvider` [#8131](https://github.com/AnalyticalGraphicsInc/cesium/pull/8131)
 * Fixed relative-to-center check, `depthFailAppearance` resource freeing for `Primitive` [#8044](https://github.com/AnalyticalGraphicsInc/cesium/pull/8044)
+* Reduces size of approximateTerrainHeights.json by rounding the numbers [#7959](https://github.com/AnalyticalGraphicsInc/cesium/pull/7959)
 * Fixed undefined `quadDetails` error from zooming into the map really close. [#8011](https://github.com/AnalyticalGraphicsInc/cesium/pull/8011)
 
 ### 1.61 - 2019-09-03

CONTRIBUTORS.md

@@ -234,3 +234,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 * [TJKoury](https://github.com/tjkoury)
 * [Qiming Zhang](https://github.com/bbbbx)
 * [Chris Wingler](https://github.com/chriswingler)
+* [Tinco Andringa](https://github.com/tinco)

Specs/Core/ApproximateTerrainHeightsSpec.js

@@ -30,8 +30,8 @@ describe('Core/ApproximateTerrainHeights', function() {
 
     it('getMinimumMaximumHeights computes minimum and maximum terrain heights', function() {
         var result = ApproximateTerrainHeights.getMinimumMaximumHeights(Rectangle.fromDegrees(-121.0, 10.0, -120.0, 11.0));
-        expect(result.minimumTerrainHeight).toEqualEpsilon(-476.125711887558, CesiumMath.EPSILON10);
-        expect(result.maximumTerrainHeight).toEqualEpsilon(-28.53441619873047, CesiumMath.EPSILON10);
+        expect(result.minimumTerrainHeight).toEqualEpsilon(-476.12571188755, CesiumMath.EPSILON10);
+        expect(result.maximumTerrainHeight).toEqualEpsilon(-28.53, CesiumMath.EPSILON10);
     });
 
     it('getMinimumMaximumHeights throws with no rectangle', function() {
@@ -51,8 +51,8 @@ describe('Core/ApproximateTerrainHeights', function() {
 
     it('getBoundingSphere computes a bounding sphere', function() {
         var result = ApproximateTerrainHeights.getBoundingSphere(Rectangle.fromDegrees(-121.0, 10.0, -120.0, 11.0));
-        expect(result.center).toEqualEpsilon(new Cartesian3(-3183013.8480289434, -5403772.557261968, 1154581.5817616477), CesiumMath.EPSILON10);
-        expect(result.radius).toEqualEpsilon(77884.16539096291, CesiumMath.EPSILON10);
+        expect(result.center).toEqualEpsilon(new Cartesian3(-3183013.849117281, -5403772.559109628, 1154581.5821590829), CesiumMath.EPSILON10);
+        expect(result.radius).toEqualEpsilon(77884.16321007285, CesiumMath.EPSILON10);
     });
 
     it('getBoundingSphere throws with no rectangle', function() {

gulpfile.js

@@ -23,6 +23,7 @@ var gulpInsert = require('gulp-insert');
 var gulpZip = require('gulp-zip');
 var gulpRename = require('gulp-rename');
 var gulpReplace = require('gulp-replace');
+var gulpJsonTransform = require('gulp-json-transform');
 var Promise = require('bluebird');
 var requirejs = require('requirejs');
 var Karma = require('karma');
@@ -132,6 +133,27 @@ gulp.task('requirejs', function(done) {
     }, done);
 });
 
+// optimizeApproximateTerrainHeights can be used to regenerate the approximateTerrainHeights
+// file from an overly precise terrain heights file to reduce bandwidth
+// the approximate terrain heights are only used when the terrain provider does not have this
+// information and not a high level of precision is required
+gulp.task('optimizeApproximateTerrainHeights', function() {
+    var argv = yargs.usage('Usage: optimizeApproximateTerrainHeights -p [degree of precision]').argv;
+    var precision = typeof argv.p !== undefined ? argv.p : 1;
+    precision = Math.pow(10, precision);
+    return gulp.src('Source/Assets/approximateTerrainHeightsPrecise.json')
+        .pipe(gulpJsonTransform(function(data, file) {
+            Object.entries(data).forEach(function(entry) {
+                var values = entry[1];
+                data[entry[0]] = [Math.floor(values[0] * precision) / precision,
+                                  Math.ceil(values[1] * precision) / precision ];
+            });
+            return data;
+        }))
+        .pipe(gulpRename('approximateTerrainHeights.json'))
+        .pipe(gulp.dest('Source/Assets/'));
+});
+
 function cloc() {
     var cmdLine;
     var clocPath = path.join('node_modules', 'cloc', 'lib', 'cloc');

package.json

@@ -45,6 +45,7 @@
     "glsl-strip-comments": "^1.0.0",
     "gulp": "^4.0.0",
     "gulp-insert": "^0.5.0",
+    "gulp-json-transform": "^0.4.6",
     "gulp-rename": "^1.2.2",
     "gulp-replace": "^1.0.0",
     "gulp-tap": "^1.0.1",
@@ -90,6 +91,7 @@
     "makeZipFile": "gulp makeZipFile",
     "minify": "gulp minify",
     "minifyRelease": "gulp minifyRelease",
+    "optimizeApproximateTerrainHeights": "gulp optimizeApproximateTerrainHeights -p 2",
     "release": "gulp release",
     "test": "gulp test",
     "test-all": "gulp test --all",