Cycles: switch Cycles triangle barycentric convention to match Embree/OptiX

Simplifies intersection code a little and slightly improves precision regarding
self intersection.

The parametric texture coordinate in shader nodes is still the same as before
for compatibility.

1 files changed, 5 insertions, 0 deletions

diff --git a/intern/cycles/kernel/integrator/init_from_bake.h b/intern/cycles/kernel/integrator/init_from_bake.h
index bf3f41b52b9..dd26215bcd2 100644
--- a/intern/cycles/kernel/integrator/init_from_bake.h
+++ b/intern/cycles/kernel/integrator/init_from_bake.h
@@ -155,6 +155,11 @@ ccl_device bool integrator_init_from_bake(KernelGlobals kg,
                                  1.0f - u);
   }
 
+  /* Convert from Blender to Cycles/Embree/OptiX barycentric convention. */
+  const float tmp = u;
+  u = v;
+  v = 1.0f - tmp - v;
+
   /* Position and normal on triangle. */
   const int object = kernel_data.bake.object_index;
   float3 P, Ng;