Values lower than 1.0 can be used to make the fog rendering not fully
obstruct the sky. This can be desired when using fog as a purely
atmospheric effect, without intending to use fog for open world fog
fading.
When set to 0.0, fog rendering behavior will be similar to Godot 3.x
where sky rendering was never affected by fog.
`shader_uniform` is now consistenly used across both per-shader
and per-instance shader uniform methods. This makes methods easier
to find in the class reference when looking for them.
- Increase the default non-volumetric fog density to 0.01 to make
adjustments more visible.
- Use a less saturated non-volumetric fog color by default
(a mix of the sky and horizon colors of the new default
ProceduralSkyMaterial).
- Set Volumetric Fog Gi Inject to 1.0 by default. Injecting GI results
in more realistic appearance of volumetric fog, at a very low
performance cost.
* Moved preprocessor to Shader and ShaderInclude
* Clean up RenderingServer side
* Preprocessor is separate from parser now, but it emits tokens with include location hints.
* Improved ShaderEditor validation code
* Added include file code completion
* Added notification for all files affected by a broken include.
