solstice-solver

commit f826be9a34552048d79f1eb0bf8e5785ab386909
parent 6fb46c1916722e11bba691394f154ada0123846f
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri,  2 Sep 2016 08:53:24 +0200

Fix the reflection vector in the sampling of the reflection BRDF

Diffstat:
M
src/ssol_brdf_reflection.c
 | 
9
++++-----

1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/src/ssol_brdf_reflection.c b/src/ssol_brdf_reflection.c
@@ -34,15 +34,14 @@ reflection_sample
    float dir[4])
 {
   struct brdf_reflection* reflection = data;
-  float vec[3], cosi;
+  float cosi;
   (void)rng;
   ASSERT(w && N && dir && f3_is_normalized(N) && f3_is_normalized(w) && data);
 
   /* Simply reflect the incoming direction w[3] with respect to the normal */
-  f3_minus(vec, w);
-  cosi = f3_dot(vec, N);
-  f3_mulf(dir, N, cosi);
-  f3_sub(dir, vec, dir);
+  cosi = -f3_dot(w, N);
+  f3_mulf(dir, N, 2.f*cosi);
+  f3_add(dir, dir, w);
   dir[3] = 1.f; /* pdf */
   return reflection->reflectivity;
 }