From e44de7fb9dc5e479ae787363d4dc7328097f5ad2 Mon Sep 17 00:00:00 2001
From: mgermerie <73115044+mgermerie@users.noreply.github.com>
Date: Tue, 9 Feb 2021 16:24:01 +0100
Subject: [PATCH] fix(Camera): resize preserves the scale

---
 src/Renderer/Camera.js | 30 ++++++++++++++++++++----------
 test/unit/camera.js    | 22 +++++++++++++++++++++-
 2 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/src/Renderer/Camera.js b/src/Renderer/Camera.js
index 659b7c147a..b9dfbb81b6 100644
--- a/src/Renderer/Camera.js
+++ b/src/Renderer/Camera.js
@@ -115,6 +115,7 @@ class Camera {
                     break;
             }
         }
+        this.camera3D.aspect = this.camera3D.aspect !== undefined ? this.camera3D.aspect : 1;
 
         this._viewMatrix = new THREE.Matrix4();
         this.width = width;
@@ -136,23 +137,32 @@ class Camera {
         }
     }
 
+    /**
+     * Resize the camera to a given width and height
+     *
+     * @param   {number}    width               The width to resize the camera to.
+     * @param   {number}    height              The height to resize the camera to.
+     */
     resize(width, height) {
-        this.width = width;
-        this.height = height;
-
         const ratio = width / height;
-        updatePreSse(this, this.height, this.camera3D.fov);
-
         if (this.camera3D.aspect !== ratio) {
-            this.camera3D.aspect = ratio;
             if (this.camera3D.isOrthographicCamera) {
-                const halfH = (this.camera3D.right - this.camera3D.left) * 0.5 / ratio;
-                const y = (this.camera3D.top + this.camera3D.bottom) * 0.5;
-                this.camera3D.top = y + halfH;
-                this.camera3D.bottom = y - halfH;
+                this.camera3D.zoom *= this.width / width;
+                const halfH = this.camera3D.top * this.camera3D.aspect / ratio;
+                this.camera3D.bottom = -halfH;
+                this.camera3D.top = halfH;
+            } else if (this.camera3D.isPerspectiveCamera) {
+                this.camera3D.fov = 2 * THREE.Math.radToDeg(Math.atan(
+                    (height / this.height) * Math.tan(THREE.Math.degToRad(this.camera3D.fov) / 2),
+                ));
             }
+            this.camera3D.aspect = ratio;
         }
 
+        this.width = width;
+        this.height = height;
+        updatePreSse(this, this.height, this.camera3D.fov);
+
         if (this.camera3D.updateProjectionMatrix) {
             this.camera3D.updateProjectionMatrix();
             this._viewMatrixNeedsUpdate = true;
diff --git a/test/unit/camera.js b/test/unit/camera.js
index 98201033a7..7c56e8232f 100644
--- a/test/unit/camera.js
+++ b/test/unit/camera.js
@@ -1,5 +1,5 @@
 import assert from 'assert';
-import Camera from 'Renderer/Camera';
+import Camera, { CAMERA_TYPE } from 'Renderer/Camera';
 import Coordinates from 'Core/Geographic/Coordinates';
 
 function compareWithEpsilon(a, b, epsilon) {
@@ -30,4 +30,24 @@ describe('camera', function () {
         assert.ok(compareWithEpsilon(resultCoordinates.latitude, coordinates.latitude, 10e-8));
         assert.ok(compareWithEpsilon(resultCoordinates.altitude, coordinates.altitude, 10e-8));
     });
+    it('should correctly resize camera', function () {
+        const dimensions = { width: 78, height: 89 };
+
+        const cameraPerspective = new Camera(
+            'EPSG:4978',
+            100, 50,
+        );
+        cameraPerspective.resize(dimensions.width, dimensions.height);
+        assert.equal(cameraPerspective.width, dimensions.width);
+        assert.equal(cameraPerspective.height, dimensions.height);
+
+        const cameraOrthographic = new Camera(
+            'EPSG:4978',
+            100, 50,
+            { type: CAMERA_TYPE.ORTHOGRAPHIC },
+        );
+        cameraOrthographic.resize(dimensions.width, dimensions.height);
+        assert.equal(cameraOrthographic.width, dimensions.width);
+        assert.equal(cameraOrthographic.height, dimensions.height);
+    });
 });