Fix T49187: inconsistent Normal Map node output for backfacing polygons.
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Authored by Alexander Gavrilov (angavrilov) on Aug 29 2016, 12:10 PM.

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Reviewers

Brecht Van Lommel (brecht)

Group Reviewers

Cycles

Maniphest Tasks

T49187: Incorrect and inconsistent Normal Map node output for backfacing polygons in Cycles.

Commits

rBSc376878e5421: Fix T49187: inconsistent Normal Map node output for backfacing polygons.
rC685475337ae9: Fix T49187: inconsistent Normal Map node output for backfacing polygons.
rBc376878e5421: Fix T49187: inconsistent Normal Map node output for backfacing polygons.

Summary

There basically are two issues here: in smooth mode (and all non-tangent
normal map types) it doesn't invert the normal for backfacing polys;
on the other hand for flat shaded tangent type it is inverted too soon.

This fix does a brute force correction by checking the backfacing flag.

Diff Detail

Repository: rB Blender

Event Timeline

Alexander Gavrilov (angavrilov) updated this revision to Diff 7329.Aug 29 2016, 12:10 PM

Alexander Gavrilov (angavrilov) retitled this revision from to Fix T49187: inconsistent Normal Map node output for backfacing polygons..

Alexander Gavrilov (angavrilov) added a reviewer: Cycles.

Alexander Gavrilov (angavrilov) updated this object.

Alexander Gavrilov (angavrilov) added a task: T49187: Incorrect and inconsistent Normal Map node output for backfacing polygons in Cycles..Aug 29 2016, 12:12 PM

Code and results look correct to me.

Although not entirely related to the original issue, maybe we should use faceforward() on the resulting normal, as it doesn't make much sense to have a normal pointing into the surface, but not sure if that's a good idea or not.