use transform's elevation in setLocationAtPoint()

Author: NathanMOlson

src/geo/projection/mercator_transform.test.ts

@@ -53,6 +53,7 @@ describe('transform', () => {
         expect([...transform.modelViewProjectionMatrix.values()]).toEqual([3, 0, 0, 0, 0, -2.954423259036624, -0.1780177690666898, -0.17364817766693033, -0, 0.006822967915294533, -0.013222891287479163, -0.012898324631281611, -786432, 774484.3308168967, 47414.91102496082, 46270.827886319785]);
         expect(fixedLngLat(transform.screenPointToLocation(new Point(250, 250)))).toEqual({lng: 0, lat: 0});
         expect(fixedCoord(transform.screenPointToMercatorCoordinate(new Point(250, 250)))).toEqual({x: 0.5, y: 0.5, z: 0});
+        expect(fixedCoord(transform.screenPointToMercatorCoordinateAtZ(new Point(250, 250), 1))).toEqual({x: 0.5, y: 0.5000000044, z: 1});
         expect(transform.locationToScreenPoint(new LngLat(0, 0))).toEqual({x: 250, y: 250});
     });
 
@@ -660,8 +661,6 @@ describe('transform', () => {
         transform.setElevation(centerInfo.elevation);
         transform.setBearing(bearing);
         transform.setPitch(pitch);
-        console.log(centerInfo);
-        console.log(transform);
         expect(transform.zoom).toBeGreaterThan(0);
         expect(transform.getCameraAltitude()).toBeCloseTo(camAlt, 10);
         expect(transform.getCameraLngLat().lng).toBeCloseTo(camLngLat.lng, 10);

src/geo/projection/mercator_transform.ts

@@ -297,8 +297,9 @@ export class MercatorTransform implements ITransform {
     }
 
     setLocationAtPoint(lnglat: LngLat, point: Point) {
-        const a = this.screenPointToMercatorCoordinate(point);
-        const b = this.screenPointToMercatorCoordinate(this.centerPoint);
+        const z = mercatorZfromAltitude(this.elevation, this.center.lat);
+        const a = this.screenPointToMercatorCoordinateAtZ(point, z);
+        const b = this.screenPointToMercatorCoordinateAtZ(this.centerPoint, z);
         const loc = locationToMercatorCoordinate(lnglat);
         const newCenter = new MercatorCoordinate(
             loc.x - (a.x - b.x),
@@ -327,9 +328,13 @@ export class MercatorTransform implements ITransform {
                 return coordinate;
             }
         }
+        return this.screenPointToMercatorCoordinateAtZ(p);
+    }
+
+    screenPointToMercatorCoordinateAtZ(p: Point, mercatorZ?: number): MercatorCoordinate {
 
         // calculate point-coordinate on flat earth
-        const targetZ = 0;
+        const targetZ = mercatorZ ? mercatorZ : 0;
         // since we don't know the correct projected z value for the point,
         // unproject two points to get a line and then find the point on that
         // line with z=0
@@ -353,7 +358,8 @@ export class MercatorTransform implements ITransform {
 
         return new MercatorCoordinate(
             interpolates.number(x0, x1, t) / this.worldSize,
-            interpolates.number(y0, y1, t) / this.worldSize);
+            interpolates.number(y0, y1, t) / this.worldSize,
+            targetZ);
     }
 
     /**