Also separated Light2D in PointLight2D and DirectionalLight2D.
Used PointLight2D because its more of a point, and it does not work
the same as OmniLight (as shape depends on texture).
Added a few utility methods to Rect2D I needed.
-Removed normal/specular properties from nodes
-Create CanvasTexture, which can contain normal/specular channels
-Refactored, optimized and simplified 2D shaders
-Use atlas for light textures.
-Use a shadow atlas for shadow textures.
-Use both items aboves to make light rendering stateless (faster).
-Reorganized uniform sets for more efficiency.
It can be enabled in the Project Settings
(`rendering/quality/screen_filters/use_debanding`). It's disabled
by default as it has a small performance impact and can make
PNG screenshots much larger (due to how dithering works).
It will also slightly brighten the scene's dark areas.
As a result, it should be enabled only when banding is noticeable enough.
This closes#17006.
I couldn't find a tool that enforces it, so I went the manual route:
```
find -name "thirdparty" -prune \
-o -name "*.cpp" -o -name "*.h" -o -name "*.m" -o -name "*.mm" \
-o -name "*.glsl" > files
perl -0777 -pi -e 's/\n}\n([^#])/\n}\n\n\1/g' $(cat files)
misc/scripts/fix_style.sh -c
```
This adds a newline after all `}` on the first column, unless they
are followed by `#` (typically `#endif`). This leads to having lots
of places with two lines between function/class definitions, but
clang-format then fixes it as we enforce max one line of separation.
This doesn't fix potential occurrences of function definitions which
are indented (e.g. for a helper class defined in a .cpp), but it's
better than nothing. Also can't be made to run easily on CI/hooks so
we'll have to be careful with new code.
Part of #33027.
Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.
This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.
There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).
Part of #33027.
