Fix T42212: Singular reflection pass is incorrect in regular path tracer

Issue seems to be caused by not totally proper pdf and eval values for this
closure. Changed it so they reflect to ggx/beckmann reflection with roughness
set to 0, which is effectively the same as the sharp reflection.

2 files changed, 7 insertions, 5 deletions

diff --git a/intern/cycles/kernel/closure/bsdf_reflection.h b/intern/cycles/kernel/closure/bsdf_reflection.h
index 0baccdf155c..6b90236525d 100644
--- a/intern/cycles/kernel/closure/bsdf_reflection.h
+++ b/intern/cycles/kernel/closure/bsdf_reflection.h
@@ -70,8 +70,9 @@ ccl_device int bsdf_reflection_sample(const ShaderClosure *sc, float3 Ng, float3
 			*domega_in_dx = 2 * dot(N, dIdx) * N - dIdx;
 			*domega_in_dy = 2 * dot(N, dIdy) * N - dIdy;
 #endif
-			*pdf = 1;
-			*eval = make_float3(1, 1, 1);
+			/* Some high number for MIS. */
+			*pdf = 1e6f;
+			*eval = make_float3(1e6f, 1e6f, 1e6f);
 		}
 	}
 	return LABEL_REFLECT|LABEL_SINGULAR;
diff --git a/intern/cycles/kernel/closure/bsdf_refraction.h b/intern/cycles/kernel/closure/bsdf_refraction.h
index c4698b42060..c96ac62fafa 100644
--- a/intern/cycles/kernel/closure/bsdf_refraction.h
+++ b/intern/cycles/kernel/closure/bsdf_refraction.h
@@ -72,10 +72,11 @@ ccl_device int bsdf_refraction_sample(const ShaderClosure *sc, float3 Ng, float3
 		dIdx, dIdy, &dRdx, &dRdy, &dTdx, &dTdy,
 #endif
 		&inside);
-	
+
 	if(!inside) {
-		*pdf = 1.0f;
-		*eval = make_float3(1.0f, 1.0f, 1.0f);
+		/* Some high number for MIS. */
+		*pdf = 1e6f;
+		*eval = make_float3(1e6f, 1e6f, 1e6f);
 		*omega_in = T;
 #ifdef __RAY_DIFFERENTIALS__
 		*domega_in_dx = dTdx;