- float denom = max(4.0*max(dot(normal, -look), 0.0)*max(dot(normal, light), 0.0), 0.001);
- return max(dot(normal, light), 0.0)*light_color*(k_diff*lambert_diffuse(base_color)+k_spec*ndist*geom/denom);
+ float spec_denom = max(4.0*max(dot(normal, -look), 0.0)*max(dot(normal, light), 0.0), 0.001);
+ return max(dot(normal, light), 0.0)*light_color*(k_diff*lambert_diffuse(base_color)+k_spec*ndist*geom/spec_denom);
+}
+
+vec3 cooktorrance_environment(vec3 normal, vec3 look, vec3 base_color, float metalness, float roughness)
+{
+ vec3 f0 = mix(vec3(0.04), base_color, metalness);
+ vec2 scale_bias = texture(fresnel_lookup, vec2(roughness, max(dot(normal, -look), 0.0))).rg;
+ vec3 k_spec = f0*scale_bias.x+scale_bias.y;
+ vec3 k_diff = (1.0-k_spec)*(1.0-metalness);
+
+ return (k_diff*base_color+k_spec)*ambient_color.rgb;