Reviewers: osl-dev_googlegroups.com,

Description:
We were missing the derivatives in the I field which is important for
background shader. This little patch fixes the problem.

Please review this at http://codereview.appspot.com/186262/show

Affected files:
src/include/oslexec.h
src/liboslexec/exec.cpp


Index: src/include/oslexec.h
===================================================================
--- src/include/oslexec.h (revision 538)
+++ src/include/oslexec.h (working copy)
@@ -195,6 +195,7 @@ public:
VaryingRef<Vec3> P; ///< Position
VaryingRef<Vec3> dPdx, dPdy; ///< Partials
VaryingRef<Vec3> I; ///< Incident ray
+ VaryingRef<Vec3> dIdx, dIdy; ///< Partial derivatives for I
VaryingRef<Vec3> N; ///< Shading normal
VaryingRef<Vec3> Ng; ///< True geometric normal
VaryingRef<float> u, v; ///< Surface parameters
Index: src/liboslexec/exec.cpp
===================================================================
--- src/liboslexec/exec.cpp (revision 538)
+++ src/liboslexec/exec.cpp (working copy)
@@ -195,8 +195,16 @@ ShadingExecution::bind (ShadingContext *context, ShaderUse use,
sym.data (globals->P.ptr()); sym.step (globals->P.step());
}
} else if (sym.name() == Strings::I) {
- sym.has_derivs (false);
- sym.data (globals->I.ptr()); sym.step (globals->I.step());
+ if (globals->dIdx.ptr() && globals->dIdy.ptr()) {
+ sym.has_derivs (true);
+ void *addr = m_context->heap_allot (sym, true);
+ VaryingRef<Dual2<Vec3> > I ((Dual2<Vec3> *)addr, sym.step());
+ for (int i = 0; i < npoints(); ++i)
+ I[i].set (globals->I[i], globals->dIdx[i], globals->dIdy[i]);
+ } else {
+ sym.has_derivs (false);
+ sym.data (globals->I.ptr()); sym.step (globals->I.step());
+ }
} else if (sym.name() == Strings::N) {
sym.has_derivs (false);
sym.data (globals->N.ptr()); sym.step (globals->N.step());

LGTM

http://codereview.appspot.com/186262/show