Merge pull request #11816 from Calinou/lights-and-shadows-add-area-lights

Add documentation for area lights in 3D lights and shadows

engine_details/architecture/internal_rendering_architecture.rst

@@ -498,6 +498,10 @@ planned in a future release.
 Clustering is also used for reflection probes and decal rendering in the
 Forward+ renderer.
 
+Area lights make use of the
+`Linearly Transformed Cosines <https://eheitzresearch.wordpress.com/757-2/>`__
+technique.
+
 Shadow mapping
 ~~~~~~~~~~~~~~