This file makes it easy to have a Three.js camera follow a given open or closed spline (curve).
This code is a modification of this example in the Three.js documentation, which can also be viewed on GitHub.
First include the follow-spline JS file.
Then inside your JS make sure to do the following on initialization:
// Set your camera you want to use to the camera that is returned from
// the initialization function
camera = initFollowCamera(<scene>, [offset from center of curve], [look ahead boolean]);
// Create the object from the curve given
addTube(<curve>, [number of segments], [closed or not boolean], [number of radius segments], [mesh to use], [scale], [side to render], [color]);
And inside of your render function make sure to call renderFollowCamera();
That's it!
By default, the camera is placed inside of the curve. You can place it outside of the curve by changing the offset when instantiating the camera.
For a full example, look at this CodePen or download the files and open /examples/index.html in a web browser that runs WebGL.