This can be used to make shadows translucent for a specific light.
The light distance fade system also uses this to smoothly fade the shadow
when the light fade transition distance is greater than 0.
Adds a FramebufferCache singletion that operates the same way as UniformSetCache.
Allows creating framebuffers on the fly (and keep them cached if re-requested) such as:
```C++
RID fb = FramebufferCache::get_singleton()->get_cache(texture1,texture2);
```
`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.
Mipmap LOD bias can be useful to improve the appearance of distant
textures without increasing anisotropic filtering (or in situations
where anisotropic filtering is not effective).
`fsr_mipmap_bias` was renamed to `texture_mipmap_bias` accordingly.
The property hint now allows for greater precision as well.
- Validate format conservatively. (This is to have VRS images created regardless whether VRS attachments are supported, which avoids errors in places where the code assumes such images were created on low-spec GPUs.)
- Create a non-layered default VRS image, which is what Vulkan (and D3D12, by the way) expect.
Implement built-in classes Vector4, Vector4i and Projection.
* Two versions of Vector4 (float and integer).
* A Projection class, which is a 4x4 matrix specialized in projection types.
These types have been requested for a long time, but given they were very corner case they were not added before.
Because in Godot 4, reimplementing parts of the rendering engine is now possible, access to these types (heavily used by the rendering code) becomes a necessity.
**Q**: Why Projection and not Matrix4?
**A**: Godot does not use Matrix2, Matrix3, Matrix4x3, etc. naming convention because, within the engine, these types always have a *purpose*. As such, Godot names them: Transform2D, Transform3D or Basis. In this case, this 4x4 matrix is _always_ used as a _Projection_, hence the naming.
* 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.
