Update lights_and_shadows.rst to mention the increased drawcall by enabling shadow

This commit is contained in:
谢天
2024-01-05 14:37:52 +08:00
committed by GitHub
parent 43f0195ba1
commit 3151ea7a0d

View File

@@ -201,7 +201,12 @@ receive low-resolution shadows that may appear blocky.
To fix this, a technique named *Parallel Split Shadow Maps* (PSSM) is used.
This splits the view frustum in 2 or 4 areas. Each area gets its own shadow map.
This allows small areas close to the viewer to have the same shadow resolution
as a huge, far-away area.
as a huge, far-away area. When shadows are enabled for DirectionalLight3D, the
default shadow mode is PSSM with 4 splits. In scenarios where an object is large
enough to appear in all four splits, it results in increased draw calls. Specifically,
such an object will be rendered five times in total: once for each of the four shadow
splits and once for the final scene rendering. This can impact performance, understanding
this behavior is important for optimizing your scene and managing performance expectations.
.. image:: img/lights_and_shadows_pssm_explained.webp