[Bf-blender-cvs] [8232cf52874] blender-v3.4-release: Fix T101669: Cycles artifacts in bump map baking

[Brecht Van Lommel]

Commit: 8232cf5287445d21b7d6effb3f0e1ffb6df09adf
Author: Brecht Van Lommel
Date:   Wed Nov 9 19:35:54 2022 +0100
Branches: blender-v3.4-release
https://developer.blender.org/rB8232cf5287445d21b7d6effb3f0e1ffb6df09adf

Fix T101669: Cycles artifacts in bump map baking

After barycentric convention changes, the differentials used for bump mapping
were wrong leading to artifacts with long thin triangles.

===================================================================

M	intern/cycles/kernel/integrator/init_from_bake.h

===================================================================

diff --git a/intern/cycles/kernel/integrator/init_from_bake.h b/intern/cycles/kernel/integrator/init_from_bake.h
index 667ba949760..cc3fbe3fe39 100644
--- a/intern/cycles/kernel/integrator/init_from_bake.h
+++ b/intern/cycles/kernel/integrator/init_from_bake.h
@@ -156,6 +156,13 @@ ccl_device bool integrator_init_from_bake(KernelGlobals kg,
   u = v;
   v = 1.0f - tmp - v;
 
+  const float tmpdx = dudx;
+  const float tmpdy = dudy;
+  dudx = dvdx;
+  dudy = dvdy;
+  dvdx = -tmpdx - dvdx;
+  dvdy = -tmpdy - dvdy;
+
   /* Position and normal on triangle. */
   const int object = kernel_data.bake.object_index;
   float3 P, Ng;