star-sf

commit 5a40091b2ee0c091749c60e57d612939f1a32de0
parent b0517721d55aff895bdb70982d063b54aa7976d6
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri, 20 Jul 2018 13:54:23 +0200

Fix the HG test

Diffstat:
M
src/test_ssf_phase_hg.c
 | 
15
+++++++++------

1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/src/test_ssf_phase_hg.c b/src/test_ssf_phase_hg.c
@@ -56,27 +56,30 @@ main(int argc, char** argv)
     ssp_ran_sphere_uniform(rng, wo, NULL);
     FOR_EACH(isamp, 0, NSAMPS) {
       double wi[3];
+      double w[3];
+      double weight;
       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));
-      w = d3_dot(wo, wi);
-      sum_cos += w;
-      sum_cos_sqr += w*w;
+      d3_minus(w, wo); /* Match the convention */
+      weight = d3_dot(w, wi);
+      sum_cos += weight;
+      sum_cos_sqr += weight*weight;
 
       /* HG(theta) = 1/(4*PI) * (1 - g^2) / (1 + g^2 - 2*g*cos(theta))^3/2 */
       r = ssf_phase_eval(phase, wo, wi);
-      ref = 1/(4*PI) * (1-g*g) / pow(1+g*g-2*g*d3_dot(wi,d3_minus(wo,wo)), 1.5);
+      ref = 1/(4*PI) * (1-g*g) / pow(1+g*g-2*g*d3_dot(w,wi), 1.5);
       CHK(eq_eps(r, ref, 1.e-6));
+      CHK(eq_eps(r, pdf, 1.e-6));
     }
     /* On average cos(wo, wi) should be g */
     E = sum_cos / NSAMPS;
     V = sum_cos_sqr / NSAMPS - E*E;
     SE = sqrt(V/NSAMPS);
-    CHK(eq_eps(sum_cos / NSAMPS, E, SE) == 1);
+    CHK(eq_eps(E, g, 3*SE));
   }
 
   CHK(ssf_phase_ref_put(phase) == RES_OK);