Constant SIGMA_BLUR1 

const SIGMA_BLUR1: f32 = 2.0;

Sigmas (in texels) for each blur level’s H+V pass. Each level reads from the previous one, so the cumulative σ grows like sqrt(Σ σ²). The values below give visually distinct levels: Blur1 just-soft, Blur2 noticeably hazy, Blur3 strong halos — close to what MD2 presets expect.