solstice-solver

commit 1096949a4e631dd621b00513397107e3f3d74558
parent df14b2c60b327164f71f0ce73de87849977923ef
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Tue, 18 Apr 2017 13:38:42 +0200

Fix perturbated normals in the solver

Sampled direction around the shading normal might point on the wrong
surface side wrt the sampled BSDF component.

Diffstat:
M
src/ssol_solver.c
 | 
9
+++++++++

1 file changed, 9 insertions(+), 0 deletions(-)
diff --git a/src/ssol_solver.c b/src/ssol_solver.c
@@ -388,8 +388,17 @@ point_shade
   if(d3_dot(wi, frag.Ns) <= 0) {
     r = 0;
   } else {
+    double cos_dir_Ng;
     r = ssf_bsdf_sample(bsdf, rng, wi, frag.Ns, dir, &type, &pdf);
     ASSERT(0 <= r && r <= 1);
+
+    /* Due to the shading normal, the sampled direction may point in the wrong
+     * direction wrt the sampled BSDF component. */
+    cos_dir_Ng = d3_dot(frag.Ng, dir);
+    if((cos_dir_Ng > 0 && (type & SSF_TRANSMISSION))
+    || (cos_dir_Ng < 0 && (type & SSF_REFLECTION))) {
+      r = 0;
+    }
   }
   pt->reflectivity_loss += (1 - r) * pt->weight;
   pt->weight *= r;