Method sample_emissive

tools/bloom-reference/src/main.rs:263–279

Sample emissive texture × factor. Emissive textures are sRGB- encoded per the glTF spec.

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

    /// Sample emissive texture × factor. Emissive textures are sRGB-
    /// encoded per the glTF spec.
    fn sample_emissive(&self, material: &Material, uv: Vec2) -> Vec3 {
        let factor = Vec3::from(material.emissive_factor);
        let tex_idx = match material.emissive_texture {
            Some(i) => i as usize,
            None => {
                // No texture: just the factor. But factor=[1,1,1]
                // without a texture is a common glTF default meaning
                // "use the texture if present, otherwise no emission".
                // Treat as non-emissive when there's no texture.
                return Vec3::ZERO;
            }
        };
        match self.sample_texture_srgb(tex_idx, uv) {
            Some(c) => Vec3::new(c.0, c.1, c.2) * factor,
            None => Vec3::ZERO,
        }
    }

    /// Bilinear sRGB-decoded texture sample at UV.
    fn sample_texture_srgb(&self, tex_idx: usize, uv: Vec2) -> Option<(f32, f32, f32)> {