+virtual vec3 get_environment_sample(vec3 direction, float roughness)
+{
+ float lod = (2-roughness)*roughness*(textureQueryLevels(environment_map)-1);
+ return textureLod(environment_map, env_world_matrix*direction, lod).rgb;
+}
+
+virtual vec3 get_reflection(vec3 normal, vec3 look)