kid0m4n/gorays — pull request #2 by t-mat (2013-10-03 06:57:35+00:00)
Title: Add multi-threading for C++

If you use `g++`, please add `-std=c++11 -pthread`.

```
g++ -std=c++11 -pthread -O3 rays.cpp
./a.out > rays.ppm
```