star-sf

commit 8f3648209f3944484179bd1cefe2395efb958da3
parent d622392b5b6253692c1c3868b657804f33ea8c9d
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Mon,  3 Oct 2016 16:53:09 +0200

Check the energy conservation on the Microfacet reflection test

Diffstat:
M
src/test_ssf_microfacet_reflection.c
 | 
36
++++++++++--------------------------

1 file changed, 10 insertions(+), 26 deletions(-)
diff --git a/src/test_ssf_microfacet_reflection.c b/src/test_ssf_microfacet_reflection.c
@@ -28,6 +28,9 @@ main(int argc, char** argv)
   struct ssf_fresnel* F;
   struct ssf_microfacet_distribution* D;
   struct ssp_rng* rng;
+  double N[4]; /* xyz, pdf */
+  double wo[4]; /* xyz, pdf */
+  size_t i, NSTEPS=100000;
   (void)argc, (void)argv;
 
   mem_init_proxy_allocator(&allocator, &mem_default_allocator);
@@ -49,33 +52,14 @@ main(int argc, char** argv)
   CHECK(ssf_microfacet_reflection_setup(NULL, F, D), RES_BAD_ARG);
   CHECK(ssf_microfacet_reflection_setup(bxdf, F, D), RES_OK);
 
-  /* Numerically evaluate rho */
-#if 0
-  {
-    double N[3];
-    double wo[3];
-    double wi[3];
-    double pdf;
-    double sum, sum_sqr;
-    double E, SE, V;
-    size_t i, NSTEPS=1000;
-
-    d3(N, 0, 1, 0);
-    sum = sum_sqr = 0;
-    ran_hemisphere_cos(N, wo, NULL);
-    FOR_EACH(i, 0, NSTEPS) {
-      double R;
-      R = ssf_bxdf_sample(bxdf, rng, wo, N, wi, &pdf);
-      sum += R;
-      sum_sqr += R*R;
-    }
-
-    E = sum / (double)NSTEPS;
-    V = sum_sqr / (double)NSTEPS - E*E;
-    SE = sqrt(V/(double)NSTEPS);
-    printf("%g +/- %g\n", E, SE);
+  /* Check energy conservation */
+  ssp_ran_sphere_uniform(rng, N);
+  ssp_ran_hemisphere_cos(rng, N, wo);
+  FOR_EACH(i, 0, NSTEPS) {
+    double wi[3], pdf;
+    CHECK(ssf_bxdf_sample(bxdf, rng, wo, N, wi, &pdf), 1);
+    CHECK(d3_dot(wi, N) > 0, 1);
   }
-#endif
 
   CHECK(ssf_bxdf_ref_put(bxdf), RES_OK);
   CHECK(ssf_bxdf_ref_put(dummy), RES_OK);