tray

TRay

Ray tracing in the terminal. Extending ansipixels.

Inspired by the Ray Tracing In One Weekend book.

Compared to the book:

• This version is in Go (golang)
  • Code is (imo) a lot easier to read
  • With generics to share code between colors and vectors/points yet different types sadly go generics on [3]float64 has a huge negative performance impact. so... not anymore.
• It uses goroutines to render faster (yeah go)
• It can render to any ANSI terminal (truecolor support being better)
• While also saving the full resolution as regular PNG (instead of PPM)
• Lots of (generated, mostly) tests
• You can specify a specific seed for the scene, for reproducible results
• Exact same as C++ output in benchmark/ which was used to compare and get:
• High performance (4x improvements from initial version), almost matches the single threaded C++ (and thus beats it with multiple go routines/cpu cores)
• WIP: navigation in the world

Current demo scene

(Created using tray -save example.png -r 64 -s 8 -d 50 -seed 2 > /tmp/example.ansi on a 160x45 terminal. It does take a while, 3 minutes on 11 core M3 pro)

Install

You can get the binary from releases

Or just run

CGO_ENABLED=0 go install fortio.org/tray@latest  # to install (in ~/go/bin typically) or just
CGO_ENABLED=0 go run fortio.org/tray@latest  # to run without install

or

brew install fortio/tap/tray

or even - but multicast that we need doesn't seem to work at least on docker for mac.

docker run --network host -v ~/.tray:/home/user/.tray -ti fortio/tray

Usage

Hit a key to hide the splash info. After which any key causes a re-render, 'Q' to quit.

Save the full resolution image using -save file.png.

More options (number of workers, rays per pixel, image super sampling, etc...)

tray help

flags:
  -d int
        Maximum ray bounce depth (default 12)
  -exit
        Not interactive (no raw), and exit immediately after rendering the image once (for timing purposes)
  -profile-cpu string
        Write CPU profile to file
  -r int
        Number of rays per pixel (default 64)
  -s float
        Image supersampling factor (default 4)
  -save string
        Save the rendered image to the specified PNG file
  -seed uint
        Seed for the random generators (0 randomizes each time)
  -w int
        Number of parallel workers (0 = GOMAXPROCS)

See also benchmark help for the non terminal drawing version used to check raytracer performance and output with a fixed image size (independent of terminal size/supersampling).