Function grow_alpha_texture_height 

pub fn grow_alpha_texture_height(
    current_height: u32,
    alphas_len: usize,
    resource_texture_dim: u32,
) -> Result<Option<u32>, EngineError>

The height an alpha texture currently current_height tall must be recreated at to hold alphas_len coverage bytes, or None when the existing texture already fits.

The texture grows only: a frame needing fewer alphas than the last one keeps the taller texture rather than reallocating.

Errors

Returns EngineError::AlphaCapacity on the same over-capacity condition as alpha_texture_height.