Method sample_occlusion

tools/bloom-reference/src/main.rs:310–321

Sample occlusion in [0,1]. glTF packs occlusion in R of the occlusion texture; strength blends between "no AO" (0) and "full AO" (1). Returns 1.0 (no attenuation) when absent.

(&self, material: &Material, uv: Vec2)

    /// occlusion texture; strength blends between "no AO" (0) and
    /// "full AO" (1). Returns 1.0 (no attenuation) when absent.
    fn sample_occlusion(&self, material: &Material, uv: Vec2) -> f32 {
        let tex_idx = match material.occlusion_texture {
            Some(i) => i as usize,
            None => return 1.0,
        };
        let (r, _g, _b) = match self.sample_texture_linear(tex_idx, uv) {
            Some(c) => c,
            None => return 1.0,
        };
        // mix(1.0, r, strength)
        1.0 + (r - 1.0) * material.occlusion_strength
    }

    /// Sample a tangent-space normal from the normal texture, in
    /// [-1,1]³. Returns (0,0,1) (i.e. "no perturbation") when the