OptionallevelsOptionalthresholdLuminance threshold below which input pixels don't contribute.
OptionalsmoothingSoft-knee width around the threshold for smooth onset.
OptionalradiusUpsample filter radius in texels; controls bloom spread.
Initial canvas size in pixels (pre-downsample).
Renderer capabilities; threaded through to the buildMaterial branch.
Number of mip levels (1..12). Higher = wider, softer bloom.