public void SetSamples(int num, double exp)
 {
     sampler = new MultiJittered(num);
     sampler.MapSamplesToHemisphere(exp);
 }
 public void SetSamples(int num_samples, float exp)
 {
     Sampler = new MultiJittered(num_samples);
     Sampler.MapSamplesToHemisphere(exp);
 }