Reviewers: osl-dev_googlegroups.com,

Description:
We were forgetting to set the pdf in the eval function, plus we were
using the wrong cosine in its sampler.

Please review this at http://codereview.appspot.com/194147/show

Affected files:
src/liboslexec/bsdf_westin.cpp


Index: src/liboslexec/bsdf_westin.cpp
===================================================================
--- src/liboslexec/bsdf_westin.cpp (revision 556)
+++ src/liboslexec/bsdf_westin.cpp (working copy)
@@ -150,7 +150,8 @@ public:
float cosNI = normal_sign * m_N.dot(omega_in);
if (cosNO > 0 && cosNI > 0) {
float sinNO2 = 1 - cosNO * cosNO;
- float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * cosNI * float(M_1_PI) : 0;
+ pdf = cosNI * float(M_1_PI);
+ float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * pdf : 0;
return Color3 (westin, westin, westin);
}
return Color3 (0, 0, 0);
@@ -174,7 +175,7 @@ public:
sample_cos_hemisphere (Nf, omega_out, randu, randv, omega_in, pdf);
if (Ngf.dot(omega_in) > 0) {
// TODO: account for sheen when sampling
- float cosNO = float(M_PI) * pdf;
+ float cosNO = Nf.dot(omega_out);
float sinNO2 = 1 - cosNO * cosNO;
float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * pdf : 0;
eval.setValue(westin, westin, westin);

LGTM

http://codereview.appspot.com/194147/show