A simple raytracer in Kotlin based on the book series Raytracing in a weekend.
This is a Gradle project, and you can run it with ./gradlew run.
The result will be saved in the file image.ppm.
Final code for the first book, saved with v1.0 tag.
I've used a FixedThreadPool executor to speed up the rendering process. The number of threads depends on the number of CPUs available.