[ShaderGraph] [master] [bugfix 1296788] Bugfix for view direction node in tangent space being not using the c…

[joshua-davis]

…orrect calculation.

Do not merge before #2752

Please read the Contributing guide before making a PR.

• Read the Graphics repository & Yamato FAQ.

Checklist for PR maker

• Have you added a backport label (if needed)? For example, the need-backport-* label. After you backport the PR, the label changes to backported-*.
• Have you updated the changelog? Each package has a CHANGELOG.md file.
• Have you updated or added the documentation for your PR? When you add a new feature, change a property name, or change the behavior of a feature, it's best practice to include related documentation changes in the same PR. If you do add documentation, make sure to add the relevant Graphics Docs team member as a reviewer of the PR. If you are not sure which person to add, see the Docs team contacts sheet.
• Have you added a graphic test for your PR (if needed)? When you add a new feature, or discover a bug that tests don't cover, please add a graphic test.

---

Purpose of this PR

The calculation for the ViewNode in Tangent space used an old method that assumed the tangent space basis was orthonormal. The Transform node was updated but the view node wasn't.

---

Testing status

Tested the attached shader graph in the bug: https://fogbugz.unity3d.com/f/cases/1296788/

---

Comments to reviewers

Notes for the reviewers you have assigned.

[ghost]

TransformWorldToTangent contains a normalization step, whereas the previous algorithm doesn't normalize. Can you remove the normalization step and see if the algorithm still works? This will allow us to backport it to versions where we don't plan on normalizing the view direction coming in from URP

[ghost]

Testing has confirmed that in some cases (speedtrees for example) tangent space is not orthogonal at the vertices, so the vertex templates need to be updates as well

[joshua-davis]

Testing has confirmed that in some cases (speedtrees for example) tangent space is not orthogonal at the vertices, so the vertex templates need to be updates as well

Updated

[ghost]

Before and after fix to vertex templates (using the following shadergraph, which offsets position if the tangent space view dir code isn't fixed)

Before:

After

That should be everything.

[ghost]

"Tanget" should be "Tangent"

[joshua-davis]

Nice catch. Fixed

[ghost]

Typo fixed, reapproving

[joshua-davis]

Failures on HDRP match current state of master