draw_state::preset::blend::ADD

pub const ADD: Blend = Blend {
	    color: BlendChannel {
            equation: Equation::Add,
            source: Factor::One,
            destination: Factor::One,
        },
        alpha: BlendChannel {
            equation: Equation::Add,
            source: Factor::One,
            destination: Factor::One,
        },
    }

When combining two fragments, add their values together, saturating at 1.0