Esena (from the bisaya word which means "Scene"") is a ray tracer written in Scala.
Right now, the program generates a PPM file. You need a software that can understand the PPM format, like GIMP, to view the rendered output.
Here is the current rendered image:
Note: This isn't the final output yet. There is also an on-going Rust version of this project. The latter is currently being given more attention so this project's development has been indefinitely stopped.
See The Ray Tracer Challenge for an excellent read on how to implement your own ray tracer. This project uses that book as the primary source of information.