The built-in ALPHA in spatial shaders comes pre-set with a per-instance
transparency value. Multiply by it if you want to keep it.
The transparency value of any given GeometryInstance3D is affected by:
- Its new "transparency" property.
- Its own visiblity range when the new "visibility_range_fade_mode"
property is set to "Self".
- Its parent visibility range when the parent's fade mode is
set to "Dependencies".
The "Self" mode will fade-out the instance when reaching the visibility
range limits, while the "Dependencies" mode will fade-in its
dependencies.
Per-instance transparency is only implemented in the forward clustered
renderer, support for mobile should be added in the future.
Co-authored-by: reduz <reduzio@gmail.com>
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