path tracing benchmark

[Trass3r]

I ported smallpt to D some time ago and now that I've working versions of  
LDC2 and GDC2 I did a quick comparison:

Original code:
http://kevinbeason.com/smallpt/explicit.cpp

D version:
https://bitbucket.org/trass3r/smallptd/src


C++ -- g++ -O3 explicit.cpp:

Rendering (4 spp) 100.00%
real	0m28.477s
user	0m26.470s
sys	0m0.160s

D -- dmd -release -O -inline -noboundscheck smallpt.d -ofsmallptDMD:
real	1m32.687s
user	1m30.820s
sys	0m0.300s

D -- gdc -frelease -fno-bounds-check -O3 smallpt.d -o smallptGDC:
real	0m52.598s
user	0m48.900s
sys	0m0.150s

D -- ldc2 -O3 -release -enable-inlining smallpt.d -ofsmallptLDC:
real	0m39.622s
user	0m36.100s
sys	0m0.240s