Use Math.log2 instead of Math.log / Math.LN2 (internal-6161)

GitOrigin-RevId: e3b43cb7e4a36dbb1cbee1b3f9e2458a988c8cc7

Author: stepankuzmin

src/geo/projection/adjustments.ts

@@ -47,7 +47,7 @@ export function getProjectionInterpolationT(
     // The interpolation ranges are manually defined based on what makes
     // sense in a 1024px wide map. Adjust the ranges to the current size
     // of the map. The smaller the map, the earlier you can start unskewing.
-    const rangeAdjustment = Math.log(size / 1024) / Math.LN2;
+    const rangeAdjustment = Math.log2(size / 1024);
     const zoomA = range[0] + rangeAdjustment;
     const zoomB = range[1] + rangeAdjustment;
     const t = smoothstep(zoomA, zoomB, zoom);
@@ -80,7 +80,7 @@ export function getZoomAdjustment(projection: Projection, loc: LngLat) {
 
     const scale = Math.sqrt((mdx * mdx + mdy * mdy) / (pdx * pdx + pdy * pdy));
 
-    return Math.log(scale) / Math.LN2;
+    return Math.log2(scale);
 }
 
 function getShearAdjustment(projection: Projection, zoom: number, loc: LngLat, interpT: number, withoutRotation?: boolean) {

src/geo/transform.ts

@@ -1551,7 +1551,7 @@ class Transform {
     get unmodified(): boolean { return this._unmodified; }
 
     zoomScale(zoom: number): number { return Math.pow(2, zoom); }
-    scaleZoom(scale: number): number { return Math.log(scale) / Math.LN2; }
+    scaleZoom(scale: number): number { return Math.log2(scale); }
 
     // Transform from LngLat to Point in world coordinates [-180, 180] x [90, -90] --> [0, this.worldSize] x [0, this.worldSize]
     project(lnglat: LngLat): Point {

src/source/image_source.ts

@@ -841,7 +841,7 @@ export function getCoordinatesCenterTileID(coords: Array<MercatorCoordinate>): C
     const dx = maxX - minX;
     const dy = maxY - minY;
     const dMax = Math.max(dx, dy);
-    const zoom = Math.max(0, Math.floor(-Math.log(dMax) / Math.LN2));
+    const zoom = Math.max(0, Math.floor(-Math.log2(dMax)));
     const tilesAtZoom = Math.pow(2, zoom);
 
     let x = Math.floor((minX + maxX) / 2 * tilesAtZoom);

src/style-spec/expression/definitions/index.ts

@@ -388,7 +388,7 @@ CompoundExpression.register(expressions, {
     'log2': [
         NumberType,
         [NumberType],
-        (ctx, [n]) => Math.log(n.evaluate(ctx)) / Math.LN2
+        (ctx, [n]) => Math.log2(n.evaluate(ctx))
     ],
     'sin': [
         NumberType,

src/ui/handler/touch_zoom_rotate.ts

@@ -105,7 +105,7 @@ function getTouchById(mapTouches: Array<Touch>, points: Array<Point>, identifier
 const ZOOM_THRESHOLD = 0.1;
 
 function getZoomDelta(distance: number, lastDistance: number) {
-    return Math.log(distance / lastDistance) / Math.LN2;
+    return Math.log2(distance / lastDistance);
 }
 
 export class TouchZoomHandler extends TwoTouchHandler {

src/util/util.ts

@@ -362,7 +362,7 @@ export function uuid(): string {
  * @private
  */
 export function isPowerOfTwo(value: number): boolean {
-    return (Math.log(value) / Math.LN2) % 1 === 0;
+    return (Math.log2(value)) % 1 === 0;
 }
 
 /**
@@ -371,7 +371,7 @@ export function isPowerOfTwo(value: number): boolean {
  */
 export function nextPowerOfTwo(value: number): number {
     if (value <= 1) return 1;
-    return Math.pow(2, Math.ceil(Math.log(value) / Math.LN2));
+    return Math.pow(2, Math.ceil(Math.log2(value)));
 }
 
 /**
@@ -380,7 +380,7 @@ export function nextPowerOfTwo(value: number): number {
  */
 export function prevPowerOfTwo(value: number): number {
     if (value <= 1) return 1;
-    return Math.pow(2, Math.floor(Math.log(value) / Math.LN2));
+    return Math.pow(2, Math.floor(Math.log2(value)));
 }
 
 /**

test/unit/geo/transform.test.ts

@@ -36,7 +36,7 @@ describe('transform', () => {
         expect(transform.size.equals(new Point(500, 500))).toEqual(true);
         expect(transform.centerPoint.equals(new Point(250, 250))).toEqual(true);
         expect(transform.scaleZoom(0)).toEqual(-Infinity);
-        expect(transform.scaleZoom(10)).toEqual(3.3219280948873626);
+        expect(transform.scaleZoom(10)).toEqual(3.321928094887362);
         expect(transform.point).toEqual(new Point(262144, 262144));
         expect(transform.height).toEqual(500);
         expect(fixedLngLat(transform.pointLocation(new Point(250, 250)))).toEqual({lng: 0, lat: -0});