Function bloom_upsample_fragment

pub fn bloom_upsample_fragment(
    slab: &[u32],
    texture: &Image2d,
    sampler: &Sampler,
    in_uv: Vec2,
    filter_radius_id: Id<Vec2>,
    upsample: &mut Vec4,
)

Bloom upsampling shader.

This shader performs successive upsampling on a source texture.

Taken from Call Of Duty method, presented at ACM Siggraph 2014.