star-sf

commit d7de821f5287bd8cba8392849c5251ed27efa118
parent 46e0e9b89ecbd6afb1287ecc623dab288b5ddda4
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 19 Jul 2018 08:40:47 +0200

Test the evalfunction of the HG phase function

Diffstat:
M
src/test_ssf_phase_hg.c
 | 
7
+++++++

1 file changed, 7 insertions(+), 0 deletions(-)
diff --git a/src/test_ssf_phase_hg.c b/src/test_ssf_phase_hg.c
@@ -58,9 +58,15 @@ main(int argc, char** argv)
       double wi[3];
       double pdf;
       double w;
+      double r;
+      double ref;
       ssf_phase_sample(phase, rng, wo, wi, &pdf);
       CHK(d3_is_normalized(wi));
       CHK(eq_eps(ssf_phase_pdf(phase, wo, wi), pdf, 1.e-6));
+      r = ssf_phase_eval(phase, wo, wi);
+      /* HG(theta) = 1/(4*PI) * (1 - g^2) / (1 + g^2 - 2*g*cos(theta))^3/2 */
+      ref = 1/(4*PI) * (1-g*g) / pow(1+g*g-2*g*d3_dot(wi,wo), 1.5);
+      CHK(eq_eps(r, ref, 1.e-6));
       w = d3_dot(wo, wi);
       sum_cos += w;
       sum_cos_sqr += w*w;
@@ -81,3 +87,4 @@ main(int argc, char** argv)
   CHK(mem_allocated_size() == 0);
   return 0;
 }
+