A Demo of Ray Tracer, refer:https://github.com/ssloy/tinyraytracer/wiki/Part-1:-understandable-raytracing
the result is:
bvh: 256 * 256 took 21 seconds 512 * 512 took 87 seconds 1366 * 768 took 243 seconds
origial: 256 * 256 took 43 seconds 512 * 512 took 180 seconds 1366 * 768 took 443 seconds