Feature/orthographic camera

[frasercl]

Problem

Resolves #305: Users would like the option to switch between perspective and orthographic camera views.

Solution

• Add perspectiveCamera and orthographicCamera properties to VisGeometry
• Add the public method setCameraType to switch which of these is active in the camera property
• Add some private methods for conveniently dealing with switching between cameras (see below)
• Update some other methods to consider orthographic cameras (dolly, storeCamera, loadCamera)
• Add fov to tweakpane and make camera saving/loading/importing/exporting from there more robust
• Do some formatting and cleanup along the way

Orthographic cameras render all objects in the scene at a consistent size regardless of distance, while the size of objects in perspective cameras decreases with size. Keeping sizes of objects looking reasonably consistent when switching views requires picking a distance at which both cameras will render the same object at the same size. After some testing, I found that picking the default distance from the camera to the origin kept things looking reasonable.

Additionally, OrbitControls handles zoom differently between perspective and orthographic cameras. To zoom a perspective camera, it physically moves the camera closer to or farther from the target. To zoom an orthographic camera, it doesn't touch the distance from the camera to the target and instead modifies the camera's zoom property. A lot of the technical challenge here was a result of having to reconcile these two zoom methods sharing one controller.

Given the notes above, I added a few private methods to VisGeometry:

• getDefaultOrbitRadius: Derives the default/initial distance between the camera and the target from cameraDefault. 98% of the time this ought to be equal to DEFAULT_CAMERA_Z_POSITION (120), but trajectories with non-standard units or camera positions will expect the app to notice and keep things consistent.
• updateOrthographicFrustum: The default "size" of the orthographic camera varies with the aspect of the frame, the FOV of the perspective camera (in other words, how fast objects get smaller as they get farther from the camera), and the default orbit radius. This method updates that if anything changes.
• updateControlsZoomBounds: OrbitControls bounds how much the camera can zoom in/out by distance for perspective cameras but by zoom level for orthographic cameras. These could all be set as constants, but the relationship between them will vary if the default orbit radius changes. So this method is here to keep things consistent should that change.

I also had to make some pretty significant changes to the dolly method to handle both ways of zooming a camera.

Type of change

• New feature (non-breaking change which adds functionality)

Steps to Verify:

1. npm start
2. Click new "Camera mode" button to switch between perspective and orthographic views
3. Move/zoom the view while switching to verify that position and zoom are preserved reasonably between modes
4. Verify zooming in/out with +/- buttons works in orthographic mode
5. Open tweakpane with Ctrl+Alt+1, verify that setting/saving/loading camera state from there works too

Screenshots:

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jest coverage report 🧪

Total coverage

Status	Category	Percentage	Covered / Total
🔴	Statements	40.05%	1951/4871
🔴	Branches	43.97%	814/1851
🔴	Functions	36.76%	400/1088
🔴	Lines	40.31%	1869/4636

Status of coverage: 🟢 - ok, 🟡 - slightly more than threshold, 🔴 - under the threshold

Show files with reduced coverage 🔻

### Reduced coverage | Status | Filename | Statements | Branches | Functions | Lines | | :----: | :-------------- | :----------------- | :------- | :----------------- | :----------------- | | 🟡 | src | 77.35% | 67.92% | 50% (-1.35% 🔻) | 77.77% | | 🟢 | constants.ts | 82.35% (-4.31% 🔻) | 100% | 57.14% (-9.52% 🔻) | 81.25% (-4.46% 🔻) | | 🔴 | index.ts | 7.46% | 7.43% | 5.34% | 7.45% | | 🔴 | src/controller | 30.24% | 16.27% | 17.85% | 30.3% | | 🔴 | src/visGeometry | 19.98% | 21.97% | 25.39% | 19.98% | > Status of coverage: 🟢 - ok, 🟡 - slightly more than threshold, 🔴 - under the threshold